v0.0.49 - Added general encrypt/decrypt verbs with curve-based routing (otp, secp256k1 NIP-04/44, x25519, ml-kem-768) and updated README documentation

.test_mnemonic_otp_roundtrip.tmp

@@ -0,0 +1,13 @@
+alarm impact educate burden vague honey horn buyer sight vocal age render
+
+index 0
+
+{
+  "index": 0,
+  "nsec": "nsec1z2lrfamae2dzax7dmnlhv497uuxe4mw0m3w694upx5x54q6dgttqvzrrwl",
+  "npub": "npub1j7d7yf47w8k2kseknqjr3045jvm00u0wnt3433kk6vu67d2zamcs8ynuw4",
+  "npubHex": "979be226be71ecab4336982438beb49336f7f1ee9ae358c6d6d339af3542eef1",
+  "nsecHex": "12be34f77dca9a2e9bcddcff7654bee70d9aedcfdc5da2d781350d4a834d42d6",
+  "fipsIpv6": "fd55:b7c6:536e:26ee:a79:6e25:6f05:a85f",
+  "strDerivationPath": "m/44'/1237'/0'/0/0"
+}

Dockerfile.alpine-musl

@@ -55,7 +55,9 @@ RUN if [ "$(uname -m)" = "aarch64" ] && ! command -v aarch64-linux-gnu-gcc >/dev
 
 # Copy source files
 COPY src/ /build/src/
+COPY libotppad/ /build/libotppad/
 COPY resources/tui_continuous/ /build/resources/tui_continuous/
+COPY resources/pqclean/ /build/resources/pqclean/
 
 # Build nsigner as a fully static binary
 RUN ARCH="$(uname -m)"; \
@@ -70,6 +72,12 @@ RUN ARCH="$(uname -m)"; \
       -I/build/nostr_core_lib/nostr_core \
       -I/build/nostr_core_lib/cjson \
       -I/build/resources/tui_continuous \
+      -I/build/resources/pqclean \
+      -I/build/resources/pqclean/common \
+      -I/build/resources/pqclean/crypto_sign/ml-dsa-65 \
+      -I/build/resources/pqclean/crypto_sign/slh-dsa-128s \
+      -I/build/resources/pqclean/crypto_kem/ml-kem-768 \
+      -I/build/libotppad \
       /build/src/main.c \
       /build/src/secure_mem.c \
       /build/src/mnemonic.c \
@@ -83,6 +91,33 @@ RUN ARCH="$(uname -m)"; \
       /build/src/key_store.c \
       /build/src/socket_name.c \
       /build/src/auth_envelope.c \
+      /build/src/miner.c \
+      /build/src/pq_crypto.c \
+      /build/src/pq_drbg.c \
+      /build/src/otp_pad.c \
+      /build/src/http_listener.c \
+      /build/libotppad/libotppad.c \
+      /build/resources/pqclean/crypto_sign/ml-dsa-65/sign.c \
+      /build/resources/pqclean/crypto_sign/ml-dsa-65/poly.c \
+      /build/resources/pqclean/crypto_sign/ml-dsa-65/ntt.c \
+      /build/resources/pqclean/crypto_sign/slh-dsa-128s/sign.c \
+      /build/resources/pqclean/crypto_sign/slh-dsa-128s/hash.c \
+      /build/resources/pqclean/crypto_sign/slh-dsa-128s/thash.c \
+      /build/resources/pqclean/crypto_sign/slh-dsa-128s/utils.c \
+      /build/resources/pqclean/crypto_sign/slh-dsa-128s/wots.c \
+      /build/resources/pqclean/crypto_sign/slh-dsa-128s/fors.c \
+      /build/resources/pqclean/crypto_sign/slh-dsa-128s/address.c \
+      /build/resources/pqclean/common/fips202.c \
+      /build/resources/pqclean/common/sha2.c \
+      /build/resources/pqclean/common/crypto_backend_openssl.c \
+      /build/resources/pqclean/crypto_kem/ml-kem-768/reduce.c \
+      /build/resources/pqclean/crypto_kem/ml-kem-768/ntt.c \
+      /build/resources/pqclean/crypto_kem/ml-kem-768/cbd.c \
+      /build/resources/pqclean/crypto_kem/ml-kem-768/verify.c \
+      /build/resources/pqclean/crypto_kem/ml-kem-768/symmetric.c \
+      /build/resources/pqclean/crypto_kem/ml-kem-768/poly.c \
+      /build/resources/pqclean/crypto_kem/ml-kem-768/indcpa.c \
+      /build/resources/pqclean/crypto_kem/ml-kem-768/kem.c \
       /build/resources/tui_continuous/tui_continuous.c \
       "$NOSTR_LIB" \
       -o /build/nsigner_static \

Makefile

@@ -1,5 +1,5 @@
 CC := gcc
-CFLAGS := -Wall -Wextra -std=c99 -Os -ffunction-sections -fdata-sections -DNOSTR_ENABLE_NSIGNER_CLIENT=1 -Isrc -Iresources/nostr_core_lib -Iresources/nostr_core_lib/nostr_core -Iresources/nostr_core_lib/cjson -Iresources/tui_continuous
+CFLAGS := -Wall -Wextra -std=c99 -Os -ffunction-sections -fdata-sections -DNOSTR_ENABLE_NSIGNER_CLIENT=1 -D_GNU_SOURCE -Isrc -Ilibotppad -Iresources/nostr_core_lib -Iresources/nostr_core_lib/nostr_core -Iresources/nostr_core_lib/cjson -Iresources/tui_continuous -Iresources/pqclean -Iresources/pqclean/crypto_sign/ml-dsa-65 -Iresources/pqclean/crypto_sign/slh-dsa-128s -Iresources/pqclean/crypto_kem/ml-kem-768 -Iresources/pqclean/common
 LDFLAGS := -Wl,--gc-sections resources/nostr_core_lib/libnostr_core_x64.a -lz -ldl -lpthread -lm -lssl -lcrypto -lcurl -lsecp256k1
 
 SRC_DIR := src
@@ -10,6 +10,31 @@ EXAMPLES_DIR := examples
 
 TARGET_DEV := $(BUILD_DIR)/nsigner
 
+# PQClean ML-DSA-65 sources (Phase 3)
+PQCLEAN_DIR := resources/pqclean
+PQCLEAN_SOURCES := \
+	$(PQCLEAN_DIR)/crypto_sign/ml-dsa-65/sign.c \
+	$(PQCLEAN_DIR)/crypto_sign/ml-dsa-65/poly.c \
+	$(PQCLEAN_DIR)/crypto_sign/ml-dsa-65/ntt.c \
+	$(PQCLEAN_DIR)/crypto_sign/slh-dsa-128s/sign.c \
+	$(PQCLEAN_DIR)/crypto_sign/slh-dsa-128s/hash.c \
+	$(PQCLEAN_DIR)/crypto_sign/slh-dsa-128s/thash.c \
+	$(PQCLEAN_DIR)/crypto_sign/slh-dsa-128s/utils.c \
+	$(PQCLEAN_DIR)/crypto_sign/slh-dsa-128s/wots.c \
+	$(PQCLEAN_DIR)/crypto_sign/slh-dsa-128s/fors.c \
+	$(PQCLEAN_DIR)/crypto_sign/slh-dsa-128s/address.c \
+	$(PQCLEAN_DIR)/common/fips202.c \
+	$(PQCLEAN_DIR)/common/sha2.c \
+	$(PQCLEAN_DIR)/common/crypto_backend_openssl.c \
+	$(PQCLEAN_DIR)/crypto_kem/ml-kem-768/reduce.c \
+	$(PQCLEAN_DIR)/crypto_kem/ml-kem-768/ntt.c \
+	$(PQCLEAN_DIR)/crypto_kem/ml-kem-768/cbd.c \
+	$(PQCLEAN_DIR)/crypto_kem/ml-kem-768/verify.c \
+	$(PQCLEAN_DIR)/crypto_kem/ml-kem-768/symmetric.c \
+	$(PQCLEAN_DIR)/crypto_kem/ml-kem-768/poly.c \
+	$(PQCLEAN_DIR)/crypto_kem/ml-kem-768/indcpa.c \
+	$(PQCLEAN_DIR)/crypto_kem/ml-kem-768/kem.c
+
 SOURCES := \
 	$(SRC_DIR)/main.c \
 	$(SRC_DIR)/secure_mem.c \
@@ -24,6 +49,13 @@ SOURCES := \
 	$(SRC_DIR)/key_store.c \
 	$(SRC_DIR)/socket_name.c \
 	$(SRC_DIR)/auth_envelope.c \
+	$(SRC_DIR)/miner.c \
+	$(SRC_DIR)/pq_crypto.c \
+	$(SRC_DIR)/pq_drbg.c \
+	$(SRC_DIR)/otp_pad.c \
+	$(SRC_DIR)/http_listener.c \
+	libotppad/libotppad.c \
+	$(PQCLEAN_SOURCES) \
 	resources/tui_continuous/tui_continuous.c
 
 HEADERS :=
@@ -40,16 +72,29 @@ TEST_SOCKET_NAME_TARGET := $(BUILD_DIR)/test_socket_name
 TEST_AUTH_ENVELOPE_TARGET := $(BUILD_DIR)/test_auth_envelope
 TEST_QREXEC_AUTH_TARGET := $(BUILD_DIR)/test_qrexec_auth
 TEST_MNEMONIC_INPUT_TARGET := $(BUILD_DIR)/test_mnemonic_input
+TEST_MINE_EVENT_TARGET := $(BUILD_DIR)/test_mine_event
+TEST_PQ_CRYPTO_TARGET := $(BUILD_DIR)/test_pq_crypto
+TEST_ED25519_X25519_TARGET := $(BUILD_DIR)/test_ed25519_x25519
+TEST_ML_DSA_65_TARGET := $(BUILD_DIR)/test_ml_dsa_65
+TEST_SLH_DSA_128S_TARGET := $(BUILD_DIR)/test_slh_dsa_128s
+TEST_ML_KEM_768_TARGET := $(BUILD_DIR)/test_ml_kem_768
+TEST_PUBKEY_FORMAT_TARGET := $(BUILD_DIR)/test_pubkey_format
+TEST_ALGORITHM_API_TARGET := $(BUILD_DIR)/test_algorithm_api
 EXAMPLE_GET_PUBLIC_KEY_TARGET := $(BUILD_DIR)/example_get_public_key_client
 EXAMPLE_SIGN_EVENT_TARGET := $(BUILD_DIR)/example_sign_event_client
 EXAMPLE_GET_PUBKEY_TCP_TARGET := $(BUILD_DIR)/example_get_pubkey_tcp
+EXAMPLE_GET_PUBKEY_QREXEC_TARGET := $(BUILD_DIR)/example_get_pubkey_qrexec
+EXAMPLE_PQ_SIGN_TARGET := $(BUILD_DIR)/example_pq_sign
+EXAMPLE_PQ_KEM_TARGET := $(BUILD_DIR)/example_pq_kem
+EXAMPLE_SSH_SIGN_TARGET := $(BUILD_DIR)/example_ssh_sign
+DEMO_C99_TARGET := $(BUILD_DIR)/demo_c99
 
-.PHONY: all lib dev static static-debug static-arm64 firmware-feather test test-integration test-mnemonic test-mnemonic-input test-role test-selector test-enforcement test-dispatcher test-policy test-socket-name test-auth-envelope test-qrexec-auth examples test-client clean
+.PHONY: all lib dev static static-debug static-arm64 firmware-feather test test-integration test-mnemonic test-mnemonic-input test-role test-selector test-enforcement test-dispatcher test-policy test-socket-name test-auth-envelope test-qrexec-auth test-mine-event test-pq-crypto test-ed25519-x25519 test-ml-dsa-65 test-slh-dsa-128s test-ml-kem-768 test-pubkey-format test-algorithm-api examples test-client clean
 
 all: dev
 
 lib:
-	cd resources/nostr_core_lib && ./build.sh --nips=1,4,6,19,44
+	cd resources/nostr_core_lib && ./build.sh --nips=1,4,6,13,19,44
 
 dev: lib $(TARGET_DEV)
 
@@ -72,7 +117,7 @@ static-arm64:
 firmware-feather:
 	cd firmware/feather_s3_tft && idf.py build
 
-test: lib test-mnemonic test-mnemonic-input test-role test-selector test-enforcement test-dispatcher test-policy test-socket-name test-auth-envelope test-qrexec-auth test-client
+test: lib test-mnemonic test-mnemonic-input test-role test-selector test-enforcement test-dispatcher test-policy test-socket-name test-auth-envelope test-qrexec-auth test-mine-event test-pq-crypto test-ed25519-x25519 test-ml-dsa-65 test-slh-dsa-128s test-ml-kem-768 test-pubkey-format test-client
 
 test-integration: $(TEST_INTEGRATION_TARGET) $(TARGET_DEV)
 	./$(TEST_INTEGRATION_TARGET)
@@ -107,9 +152,33 @@ test-auth-envelope: $(TEST_AUTH_ENVELOPE_TARGET)
 test-qrexec-auth: $(TEST_QREXEC_AUTH_TARGET) $(TARGET_DEV)
 	./$(TEST_QREXEC_AUTH_TARGET)
 
+test-mine-event: $(TEST_MINE_EVENT_TARGET) $(TARGET_DEV)
+	./$(TEST_MINE_EVENT_TARGET)
+
+test-pq-crypto: $(TEST_PQ_CRYPTO_TARGET)
+	./$(TEST_PQ_CRYPTO_TARGET)
+
+test-ed25519-x25519: $(TEST_ED25519_X25519_TARGET)
+	./$(TEST_ED25519_X25519_TARGET)
+
+test-ml-dsa-65: $(TEST_ML_DSA_65_TARGET)
+	./$(TEST_ML_DSA_65_TARGET)
+
+test-slh-dsa-128s: $(TEST_SLH_DSA_128S_TARGET)
+	./$(TEST_SLH_DSA_128S_TARGET)
+
+test-ml-kem-768: $(TEST_ML_KEM_768_TARGET)
+	./$(TEST_ML_KEM_768_TARGET)
+
+test-pubkey-format: $(TEST_PUBKEY_FORMAT_TARGET)
+	./$(TEST_PUBKEY_FORMAT_TARGET)
+
+test-algorithm-api: $(TEST_ALGORITHM_API_TARGET)
+	./$(TEST_ALGORITHM_API_TARGET)
+
 test-client: examples
 
-examples: $(EXAMPLE_GET_PUBLIC_KEY_TARGET) $(EXAMPLE_SIGN_EVENT_TARGET) $(EXAMPLE_GET_PUBKEY_TCP_TARGET)
+examples: $(EXAMPLE_GET_PUBLIC_KEY_TARGET) $(EXAMPLE_SIGN_EVENT_TARGET) $(EXAMPLE_GET_PUBKEY_TCP_TARGET) $(EXAMPLE_GET_PUBKEY_QREXEC_TARGET) $(EXAMPLE_PQ_SIGN_TARGET) $(EXAMPLE_PQ_KEM_TARGET) $(EXAMPLE_SSH_SIGN_TARGET) $(DEMO_C99_TARGET)
 
 $(TEST_MNEMONIC_TARGET): $(TEST_DIR)/test_mnemonic.c $(SRC_DIR)/mnemonic.c $(SRC_DIR)/secure_mem.c
 	@mkdir -p $(BUILD_DIR)
@@ -127,13 +196,13 @@ $(TEST_SELECTOR_TARGET): $(TEST_DIR)/test_selector.c $(SRC_DIR)/selector.c $(SRC
 	@mkdir -p $(BUILD_DIR)
 	$(CC) $(CFLAGS) $(TEST_DIR)/test_selector.c $(SRC_DIR)/selector.c $(SRC_DIR)/role_table.c -o $(TEST_SELECTOR_TARGET) $(LDFLAGS)
 
-$(TEST_ENFORCEMENT_TARGET): $(TEST_DIR)/test_enforcement.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c
+$(TEST_ENFORCEMENT_TARGET): $(TEST_DIR)/test_enforcement.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c $(SRC_DIR)/pq_crypto.c
 	@mkdir -p $(BUILD_DIR)
-	$(CC) $(CFLAGS) $(TEST_DIR)/test_enforcement.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c -o $(TEST_ENFORCEMENT_TARGET) $(LDFLAGS)
+	$(CC) $(CFLAGS) $(TEST_DIR)/test_enforcement.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c $(SRC_DIR)/pq_crypto.c -o $(TEST_ENFORCEMENT_TARGET) $(LDFLAGS)
 
-$(TEST_DISPATCHER_TARGET): $(TEST_DIR)/test_dispatcher.c $(SRC_DIR)/dispatcher.c $(SRC_DIR)/key_store.c $(SRC_DIR)/selector.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c $(SRC_DIR)/mnemonic.c $(SRC_DIR)/secure_mem.c
+$(TEST_DISPATCHER_TARGET): $(TEST_DIR)/test_dispatcher.c $(SRC_DIR)/dispatcher.c $(SRC_DIR)/key_store.c $(SRC_DIR)/miner.c $(SRC_DIR)/pq_crypto.c $(SRC_DIR)/pq_drbg.c $(PQCLEAN_SOURCES) $(SRC_DIR)/selector.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c $(SRC_DIR)/mnemonic.c $(SRC_DIR)/secure_mem.c
 	@mkdir -p $(BUILD_DIR)
-	$(CC) $(CFLAGS) $(TEST_DIR)/test_dispatcher.c $(SRC_DIR)/dispatcher.c $(SRC_DIR)/key_store.c $(SRC_DIR)/selector.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c $(SRC_DIR)/mnemonic.c $(SRC_DIR)/secure_mem.c -o $(TEST_DISPATCHER_TARGET) $(LDFLAGS)
+	$(CC) $(CFLAGS) $(TEST_DIR)/test_dispatcher.c $(SRC_DIR)/dispatcher.c $(SRC_DIR)/key_store.c $(SRC_DIR)/miner.c $(SRC_DIR)/pq_crypto.c $(SRC_DIR)/pq_drbg.c $(PQCLEAN_SOURCES) $(SRC_DIR)/selector.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c $(SRC_DIR)/mnemonic.c $(SRC_DIR)/secure_mem.c -o $(TEST_DISPATCHER_TARGET) $(LDFLAGS)
 
 $(TEST_POLICY_TARGET): $(TEST_DIR)/test_policy.c $(SRC_DIR)/policy.c
 	@mkdir -p $(BUILD_DIR)
@@ -155,6 +224,38 @@ $(TEST_QREXEC_AUTH_TARGET): $(TEST_DIR)/test_qrexec_auth.c $(SRC_DIR)/auth_envel
 	@mkdir -p $(BUILD_DIR)
 	$(CC) $(CFLAGS) $(TEST_DIR)/test_qrexec_auth.c $(SRC_DIR)/auth_envelope.c -o $(TEST_QREXEC_AUTH_TARGET) $(LDFLAGS)
 
+$(TEST_MINE_EVENT_TARGET): $(TEST_DIR)/test_mine_event.c $(SRC_DIR)/miner.c $(SRC_DIR)/key_store.c $(SRC_DIR)/pq_crypto.c $(SRC_DIR)/pq_drbg.c $(PQCLEAN_SOURCES) $(SRC_DIR)/dispatcher.c $(SRC_DIR)/selector.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c $(SRC_DIR)/mnemonic.c $(SRC_DIR)/secure_mem.c
+	@mkdir -p $(BUILD_DIR)
+	$(CC) $(CFLAGS) $(TEST_DIR)/test_mine_event.c $(SRC_DIR)/miner.c $(SRC_DIR)/key_store.c $(SRC_DIR)/pq_crypto.c $(SRC_DIR)/pq_drbg.c $(PQCLEAN_SOURCES) $(SRC_DIR)/dispatcher.c $(SRC_DIR)/selector.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c $(SRC_DIR)/mnemonic.c $(SRC_DIR)/secure_mem.c -o $(TEST_MINE_EVENT_TARGET) $(LDFLAGS)
+
+$(TEST_PQ_CRYPTO_TARGET): $(TEST_DIR)/test_pq_crypto.c $(SRC_DIR)/pq_crypto.c $(SRC_DIR)/role_table.c
+	@mkdir -p $(BUILD_DIR)
+	$(CC) $(CFLAGS) $(TEST_DIR)/test_pq_crypto.c $(SRC_DIR)/pq_crypto.c $(SRC_DIR)/role_table.c -o $(TEST_PQ_CRYPTO_TARGET) $(LDFLAGS)
+
+$(TEST_ED25519_X25519_TARGET): $(TEST_DIR)/test_ed25519_x25519.c $(SRC_DIR)/pq_crypto.c $(SRC_DIR)/pq_drbg.c $(PQCLEAN_SOURCES) $(SRC_DIR)/key_store.c $(SRC_DIR)/dispatcher.c $(SRC_DIR)/miner.c $(SRC_DIR)/selector.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c $(SRC_DIR)/mnemonic.c $(SRC_DIR)/secure_mem.c
+	@mkdir -p $(BUILD_DIR)
+	$(CC) $(CFLAGS) $(TEST_DIR)/test_ed25519_x25519.c $(SRC_DIR)/pq_crypto.c $(SRC_DIR)/pq_drbg.c $(PQCLEAN_SOURCES) $(SRC_DIR)/key_store.c $(SRC_DIR)/dispatcher.c $(SRC_DIR)/miner.c $(SRC_DIR)/selector.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c $(SRC_DIR)/mnemonic.c $(SRC_DIR)/secure_mem.c -o $(TEST_ED25519_X25519_TARGET) $(LDFLAGS)
+
+$(TEST_ML_DSA_65_TARGET): $(TEST_DIR)/test_ml_dsa_65.c $(SRC_DIR)/pq_crypto.c $(SRC_DIR)/pq_drbg.c $(PQCLEAN_SOURCES) $(SRC_DIR)/key_store.c $(SRC_DIR)/dispatcher.c $(SRC_DIR)/miner.c $(SRC_DIR)/selector.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c $(SRC_DIR)/mnemonic.c $(SRC_DIR)/secure_mem.c
+	@mkdir -p $(BUILD_DIR)
+	$(CC) $(CFLAGS) $(TEST_DIR)/test_ml_dsa_65.c $(SRC_DIR)/pq_crypto.c $(SRC_DIR)/pq_drbg.c $(PQCLEAN_SOURCES) $(SRC_DIR)/key_store.c $(SRC_DIR)/dispatcher.c $(SRC_DIR)/miner.c $(SRC_DIR)/selector.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c $(SRC_DIR)/mnemonic.c $(SRC_DIR)/secure_mem.c -o $(TEST_ML_DSA_65_TARGET) $(LDFLAGS)
+
+$(TEST_SLH_DSA_128S_TARGET): $(TEST_DIR)/test_slh_dsa_128s.c $(SRC_DIR)/pq_crypto.c $(SRC_DIR)/pq_drbg.c $(PQCLEAN_SOURCES) $(SRC_DIR)/key_store.c $(SRC_DIR)/dispatcher.c $(SRC_DIR)/miner.c $(SRC_DIR)/selector.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c $(SRC_DIR)/mnemonic.c $(SRC_DIR)/secure_mem.c
+	@mkdir -p $(BUILD_DIR)
+	$(CC) $(CFLAGS) $(TEST_DIR)/test_slh_dsa_128s.c $(SRC_DIR)/pq_crypto.c $(SRC_DIR)/pq_drbg.c $(PQCLEAN_SOURCES) $(SRC_DIR)/key_store.c $(SRC_DIR)/dispatcher.c $(SRC_DIR)/miner.c $(SRC_DIR)/selector.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c $(SRC_DIR)/mnemonic.c $(SRC_DIR)/secure_mem.c -o $(TEST_SLH_DSA_128S_TARGET) $(LDFLAGS)
+
+$(TEST_ML_KEM_768_TARGET): $(TEST_DIR)/test_ml_kem_768.c $(SRC_DIR)/pq_crypto.c $(SRC_DIR)/pq_drbg.c $(PQCLEAN_SOURCES) $(SRC_DIR)/key_store.c $(SRC_DIR)/dispatcher.c $(SRC_DIR)/miner.c $(SRC_DIR)/selector.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c $(SRC_DIR)/mnemonic.c $(SRC_DIR)/secure_mem.c
+	@mkdir -p $(BUILD_DIR)
+	$(CC) $(CFLAGS) $(TEST_DIR)/test_ml_kem_768.c $(SRC_DIR)/pq_crypto.c $(SRC_DIR)/pq_drbg.c $(PQCLEAN_SOURCES) $(SRC_DIR)/key_store.c $(SRC_DIR)/dispatcher.c $(SRC_DIR)/miner.c $(SRC_DIR)/selector.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c $(SRC_DIR)/mnemonic.c $(SRC_DIR)/secure_mem.c -o $(TEST_ML_KEM_768_TARGET) $(LDFLAGS)
+
+$(TEST_PUBKEY_FORMAT_TARGET): $(TEST_DIR)/test_pubkey_format.c $(SRC_DIR)/pq_crypto.c $(SRC_DIR)/pq_drbg.c $(PQCLEAN_SOURCES) $(SRC_DIR)/key_store.c $(SRC_DIR)/dispatcher.c $(SRC_DIR)/miner.c $(SRC_DIR)/selector.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c $(SRC_DIR)/mnemonic.c $(SRC_DIR)/secure_mem.c
+	@mkdir -p $(BUILD_DIR)
+	$(CC) $(CFLAGS) $(TEST_DIR)/test_pubkey_format.c $(SRC_DIR)/pq_crypto.c $(SRC_DIR)/pq_drbg.c $(PQCLEAN_SOURCES) $(SRC_DIR)/key_store.c $(SRC_DIR)/dispatcher.c $(SRC_DIR)/miner.c $(SRC_DIR)/selector.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c $(SRC_DIR)/mnemonic.c $(SRC_DIR)/secure_mem.c -o $(TEST_PUBKEY_FORMAT_TARGET) $(LDFLAGS)
+
+$(TEST_ALGORITHM_API_TARGET): $(TEST_DIR)/test_algorithm_api.c $(SRC_DIR)/pq_crypto.c $(SRC_DIR)/pq_drbg.c $(PQCLEAN_SOURCES) $(SRC_DIR)/key_store.c $(SRC_DIR)/dispatcher.c $(SRC_DIR)/miner.c $(SRC_DIR)/selector.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c $(SRC_DIR)/mnemonic.c $(SRC_DIR)/secure_mem.c $(SRC_DIR)/policy.c
+	@mkdir -p $(BUILD_DIR)
+	$(CC) $(CFLAGS) $(TEST_DIR)/test_algorithm_api.c $(SRC_DIR)/pq_crypto.c $(SRC_DIR)/pq_drbg.c $(PQCLEAN_SOURCES) $(SRC_DIR)/key_store.c $(SRC_DIR)/dispatcher.c $(SRC_DIR)/miner.c $(SRC_DIR)/selector.c $(SRC_DIR)/enforcement.c $(SRC_DIR)/role_table.c $(SRC_DIR)/mnemonic.c $(SRC_DIR)/secure_mem.c $(SRC_DIR)/policy.c -o $(TEST_ALGORITHM_API_TARGET) $(LDFLAGS)
+
 $(EXAMPLE_GET_PUBLIC_KEY_TARGET): $(EXAMPLES_DIR)/get_public_key_client.c
 	@mkdir -p $(BUILD_DIR)
 	$(CC) $(CFLAGS) $(EXAMPLES_DIR)/get_public_key_client.c -o $(EXAMPLE_GET_PUBLIC_KEY_TARGET) $(LDFLAGS)
@@ -167,5 +268,25 @@ $(EXAMPLE_GET_PUBKEY_TCP_TARGET): $(EXAMPLES_DIR)/get_pubkey_tcp.c
 	@mkdir -p $(BUILD_DIR)
 	$(CC) $(CFLAGS) $(EXAMPLES_DIR)/get_pubkey_tcp.c -o $(EXAMPLE_GET_PUBKEY_TCP_TARGET) $(LDFLAGS)
 
+$(EXAMPLE_GET_PUBKEY_QREXEC_TARGET): $(EXAMPLES_DIR)/get_pubkey_qrexec.c
+	@mkdir -p $(BUILD_DIR)
+	$(CC) $(CFLAGS) $(EXAMPLES_DIR)/get_pubkey_qrexec.c -o $(EXAMPLE_GET_PUBKEY_QREXEC_TARGET) $(LDFLAGS)
+
+$(EXAMPLE_PQ_SIGN_TARGET): $(EXAMPLES_DIR)/pq_sign_example.c
+	@mkdir -p $(BUILD_DIR)
+	$(CC) $(CFLAGS) $(EXAMPLES_DIR)/pq_sign_example.c -o $(EXAMPLE_PQ_SIGN_TARGET) $(LDFLAGS)
+
+$(EXAMPLE_PQ_KEM_TARGET): $(EXAMPLES_DIR)/pq_kem_example.c
+	@mkdir -p $(BUILD_DIR)
+	$(CC) $(CFLAGS) $(EXAMPLES_DIR)/pq_kem_example.c -o $(EXAMPLE_PQ_KEM_TARGET) $(LDFLAGS)
+
+$(EXAMPLE_SSH_SIGN_TARGET): $(EXAMPLES_DIR)/ssh_sign_example.c
+	@mkdir -p $(BUILD_DIR)
+	$(CC) $(CFLAGS) $(EXAMPLES_DIR)/ssh_sign_example.c -o $(EXAMPLE_SSH_SIGN_TARGET) $(LDFLAGS)
+
+$(DEMO_C99_TARGET): $(CLIENT_DIR)/demo_c99.c
+	@mkdir -p $(BUILD_DIR)
+	$(CC) $(CFLAGS) $(CLIENT_DIR)/demo_c99.c -o $(DEMO_C99_TARGET) $(LDFLAGS)
+
 clean:
 	rm -rf $(BUILD_DIR)

README.md

@@ -20,7 +20,8 @@ This is a **program, not a daemon**:
 - purpose/curve enforcement
 - request dispatch
 - interactive terminal UI
-- transport adapter(s)
+- transport adapter(s) (Unix socket, qrexec, FIPS/TCP, HTTP)
+- OTP one-time pad encryption (optional, with USB pad)
 
 You run it when you need signing. You stop it when you are done. Closing the terminal or quitting the program ends the trust session and destroys state.
 
@@ -74,9 +75,16 @@ When started, `n_signer` immediately enters terminal input mode:
    - On `E`: prompt for mnemonic with terminal echo disabled, then validate.
    - On `G`: generate a fresh 12-word BIP-39 mnemonic from `getrandom(2)`, display it numbered with a "WRITE THIS DOWN — IT WILL NOT BE SHOWN AGAIN" warning, then continue. There is no confirmation step.
 2. Build in-memory role/selector state from the mnemonic.
-3. Pick the abstract socket name (random BIP-39 pair, or `--socket-name` / `--name` / `-n` override).
-4. Initialize transport endpoints and bind the socket.
-5. Switch to running status display, with the signer name and socket address shown in the banner.
+3. **Interactive transport selection** (if no `--listen` flag given and stdin is a TTY): choose one or more of:
+   - Local Unix socket
+   - Qubes qrexec bridge
+   - FIPS/TCP listener (framed JSON)
+   - HTTP listener (curl-friendly)
+4. **Index whitelist** (optional): restrict which `nostr_index` values this session can access.
+5. **OTP pad selection** (optional): auto-scans attached USB drives for OTP pads and offers to bind one. See [`plans/otp_nostr_integration.md`](plans/otp_nostr_integration.md).
+6. Pick the abstract socket name (random BIP-39 pair, or `--socket-name` / `--name` / `-n` override).
+7. Initialize transport endpoints and bind the socket.
+8. Switch to running status display, with the signer name, socket address, and OTP pad status shown in the banner.
 
 No startup files are read or written. The mnemonic — typed or generated — lives only in `mlock`'d memory and is zeroized on shutdown or crash.
 
@@ -93,7 +101,15 @@ After unlock, terminal becomes a live status and control console. Example layout
 
 ```text
 n_signer v0.x  |  foreground session active
-transport: unix-abstract:@nsigner
+
+Connections
+Server: unix @nsigner (bridge-source-trusted)
+  Client: nsigner --socket-name nsigner client '<json>'
+  Qrexec: qrexec-client-vm <target_qube> qubes.NsignerRpc
+Server: HTTP 127.0.0.1:11111
+  Client: curl -X POST http://127.0.0.1:11111/ -H 'Content-Type: application/json' -d '<json>'
+OTP pad: 333e9902db839d9d... (offset 288 / 1048576 bytes)
+
 session: unlocked (RAM-only)
 
 Roles
@@ -169,6 +185,145 @@ A single memorized mnemonic can deterministically recover multiple key domains t
 
 Examples include Nostr roles, Bitcoin branches, and future application-specific paths. See [`plans/seed_phrase_uses.md`](plans/seed_phrase_uses.md) for the maintained use-case catalog and caveats.
 
+## 4b. Crypto palette
+
+`n_signer` supports six cryptographic algorithms, all derived deterministically from the same BIP-39 mnemonic. Each algorithm is bound to a specific `(purpose, curve)` pair and a distinct BIP-44 derivation path.
+
+### 4b.1 Algorithms
+
+| Algorithm | Curve label | Purpose | FIPS standard | Key sizes (priv / pub) | Derivation path |
+|---|---|---|---|---|---|
+| secp256k1 | `secp256k1` | `nostr` | — | 32 / 32 bytes | `m/44'/1237'/<n>'/0/0` (NIP-06) |
+| ed25519 | `ed25519` | `ssh` | — | 32 / 32 bytes | `m/44'/102001'/<n>'/0'/0'` (SLIP-0010) |
+| x25519 | `x25519` | `age` | — | 32 / 32 bytes | `m/44'/102002'/<n>'/0'/0'` (SLIP-0010) |
+| ML-DSA-65 | `ml-dsa-65` | `pq-sig` | FIPS 204 | 4032 / 1952 bytes | `m/44'/102003'/<n>'/0'/0'` → seed → DRBG → PQClean keygen |
+| SLH-DSA-128s | `slh-dsa-128s` | `pq-sig` | FIPS 205 | 64 / 32 bytes | `m/44'/102004'/<n>'/0'/0'` → seed → DRBG → PQClean keygen |
+| ML-KEM-768 | `ml-kem-768` | `pq-kem` | FIPS 203 | 2400 / 1184 bytes | `m/44'/102005'/<n>'/0'/0'` → seed → DRBG → PQClean keygen |
+
+All six algorithms are always compiled in on every target (host x86_64 static binary and ESP32 firmware). The PQ implementations are vendored from [PQClean](https://github.com/PQClean/PQClean) (public domain / CC0).
+
+### 4b.2 Key derivation
+
+All keys derive deterministically from the BIP-39 mnemonic:
+
+- **secp256k1** uses standard BIP-32/NIP-06 derivation. The 32-byte path output is the private key scalar.
+- **ed25519 / x25519** use SLIP-0010 HMAC-SHA512 derivation (all-hardened paths, as required by SLIP-0010 for ed25519). The 32-byte output is the private key.
+- **PQ algorithms** (ML-DSA-65, SLH-DSA-128s, ML-KEM-768) use a two-stage approach: the mnemonic-derived 32-byte seed feeds a SHAKE-256 DRBG (NIST SP 800-90A style), which replaces PQClean's `randombytes()` callback during keygen. This produces deterministic PQ key pairs from the mnemonic — same mnemonic, same role, same key pair every time. See [`documents/SECURITY.md`](documents/SECURITY.md) §17 for the security argument.
+
+The new algorithms use BIP-44 coin types `102001`–`102005` (unregistered in SLIP-44, chosen to avoid collisions with real cryptocurrencies). All non-secp256k1 paths are fully hardened per SLIP-0010.
+
+### 4b.3 Post-quantum context
+
+The three post-quantum algorithms address the **harvest-now-decrypt-later** threat: an adversary recording encrypted traffic today to decrypt it once a quantum computer becomes available. ML-KEM-768 protects key agreement against this threat. ML-DSA-65 and SLH-DSA-128s protect signatures against future quantum forgery.
+
+All three are FIPS-standardized (FIPS 203, 204, 205) and are provided as **additional options**, not replacements for secp256k1. Nostr continues to use secp256k1 exclusively. PQ algorithms are opt-in per role.
+
+Note: OpenSSH does not yet support PQ signing keys. The `pq-sig` purpose is forward-looking — the primitives are ready for when the ecosystem adopts them.
+
+### 4b.4 Structured `get_public_key` response
+
+For secp256k1, `get_public_key` returns the plain 64-hex-char public key string (backward compatible). An optional `{"format": "structured"}` in the options object requests a structured JSON response.
+
+For all other algorithms (ed25519, x25519, ML-DSA-65, SLH-DSA-128s, ML-KEM-768), `get_public_key` always returns a structured JSON object (serialized as a string):
+
+```json
+{"algorithm": "ml-dsa-65", "public_key": "<hex>", "key_id": "<16 hex chars>"}
+```
+
+The `key_id` is a short display identifier (first 16 hex chars of the public key). PQ public keys are large (ML-DSA-65: 3904 hex chars; ML-KEM-768: 2368 hex chars).
+
+## 4c. Algorithm-based API
+
+In addition to the role-based API, n_signer supports an **algorithm-based API** where the caller specifies the algorithm and derivation index directly, without needing to know role names. This is the preferred API for new clients.
+
+### 4c.1 New verbs
+
+| Verb | Description | Algorithm parameter | Key parameter |
+|---|---|---|---|
+| `sign` | Sign arbitrary bytes | `algorithm` | `index` |
+| `verify` | Verify a signature | `algorithm` | `index` |
+| `encapsulate` | KEM encapsulation | `algorithm` | `public_key` (peer's) |
+| `decapsulate` | KEM decapsulation | `algorithm` | `index` |
+| `derive_shared_secret` | ECDH key agreement (x25519) | `algorithm` | `index` + `peer_public_key` |
+| `get_public_key` | Get public key (algorithm-based) | `algorithm` | `index` |
+
+### 4c.2 Algorithm names
+
+| String | Algorithm | Key type |
+|---|---|---|
+| `secp256k1` | secp256k1 (Schnorr/ECDSA) | Signature |
+| `ed25519` | ed25519 | Signature |
+| `ml-dsa-65` | ML-DSA-65 (FIPS 204) | Signature |
+| `slh-dsa-128s` | SLH-DSA-128s (FIPS 205) | Signature |
+| `x25519` | X25519 (ECDH) | Key agreement |
+| `ml-kem-768` | ML-KEM-768 (FIPS 203) | KEM |
+
+### 4c.3 Request examples
+
+**Sign with ed25519:**
+```json
+{"id":"1","method":"sign","params":["68656c6c6f",{"algorithm":"ed25519","index":0}]}
+```
+Response: `{"id":"1","result":{"signature":"<hex>","algorithm":"ed25519","key_id":"<16hex>"}}`
+
+**Sign with secp256k1 (ECDSA scheme):**
+```json
+{"id":"2","method":"sign","params":["68656c6c6f",{"algorithm":"secp256k1","index":0,"scheme":"ecdsa"}]}
+```
+The `scheme` parameter is optional for secp256k1: `"schnorr"` (default, BIP-340) or `"ecdsa"`.
+
+**Get public key (algorithm-based):**
+```json
+{"id":"3","method":"get_public_key","params":[{"algorithm":"ml-dsa-65","index":0}]}
+```
+Response: `{"id":"3","result":{"algorithm":"ml-dsa-65","public_key":"<hex>","key_id":"<16hex>"}}`
+
+**KEM encapsulate:**
+```json
+{"id":"4","method":"encapsulate","params":["<peer_pubkey_hex>",{"algorithm":"ml-kem-768"}]}
+```
+
+**KEM decapsulate:**
+```json
+{"id":"5","method":"decapsulate","params":["<ciphertext_hex>",{"algorithm":"ml-kem-768","index":0}]}
+```
+
+**ECDH shared secret (x25519):**
+```json
+{"id":"6","method":"derive_shared_secret","params":["<peer_pubkey_hex>",{"algorithm":"x25519","index":0}]}
+```
+
+### 4c.4 Verb aliases
+
+These verb aliases are also available. When used with the `algorithm` parameter, they map to the algorithm-based verbs:
+
+| Alias | Canonical verb | Default algorithm |
+|---|---|---|
+| `sign_data` | `sign` | (from `algorithm` parameter) |
+| `ssh_sign` | `sign` | `ed25519` |
+| `verify_signature` | `verify` | (from `algorithm` parameter) |
+| `kem_encapsulate` | `encapsulate` | `ml-kem-768` |
+| `kem_decapsulate` | `decapsulate` | `ml-kem-768` |
+
+Without the `algorithm` parameter, these aliases fall through to the role-based path (backward compatible).
+
+### 4c.5 Algorithm-based preapprove
+
+```
+nsigner --preapprove caller=uid:1000,algorithm=ed25519,index=0-4,verb=sign,verify
+nsigner --preapprove caller=uid:1000,algorithm=ml-kem-768,index=0,verb=decapsulate
+```
+
+### 4c.6 Enforcement matrix
+
+| Verb | Valid algorithms |
+|---|---|
+| `sign` / `verify` | secp256k1, ed25519, ml-dsa-65, slh-dsa-128s |
+| `encapsulate` / `decapsulate` | ml-kem-768 |
+| `derive_shared_secret` | x25519 |
+| `get_public_key` | all algorithms |
+| `sign_event` / `nip44_*` / `nip04_*` / `mine_event` | secp256k1 (Nostr protocol) |
+
 ## 5. Wire contract (JSON-RPC)
 
 Request shape is JSON-RPC with NIP-46-style methods and optional trailing selector options.
@@ -178,14 +333,96 @@ Request shape is JSON-RPC with NIP-46-style methods and optional trailing select
 { "id": "2", "method": "sign_event", "params": ["<event_json>", { "role": "main" }] }
 { "id": "3", "method": "sign_event", "params": ["<event_json>", { "nostr_index": 7 }] }
 { "id": "4", "method": "sign_event", "params": ["<event_json>", { "role_path": "m/84'/0'/0'/0/5", "purpose": "bitcoin", "curve": "secp256k1" }] }
+{ "id": "5", "method": "mine_event", "params": ["<event_json>", { "difficulty": 20, "threads": 4, "timeout_sec": 30, "nostr_index": 0 }] }
 ```
 
 Implemented signer verbs in this build:
 
+**Nostr verbs** (secp256k1 only, use `role` or `nostr_index` selector):
+
 - `get_public_key`
 - `sign_event`
 - `nip04_encrypt` / `nip04_decrypt`
 - `nip44_encrypt` / `nip44_decrypt`
+- `mine_event` — add NIP-13 proof-of-work and sign (see below)
+
+**Algorithm-based verbs** (use `algorithm` + `index` selector, no role needed):
+
+| Verb | Valid algorithms | Description |
+|---|---|---|
+| `sign` | secp256k1, ed25519, ml-dsa-65, slh-dsa-128s | Sign arbitrary bytes. Returns `{"signature":"<hex>","algorithm":"<alg>","key_id":"<16hex>"}`. |
+| `verify` | secp256k1, ed25519, ml-dsa-65, slh-dsa-128s | Verify a signature. Returns `{"valid":true/false}`. |
+| `encapsulate` | ml-kem-768 | Encapsulate against a peer's ML-KEM-768 public key. Returns `{"ciphertext":"<hex>","shared_secret":"<hex>","algorithm":"ml-kem-768"}`. |
+| `decapsulate` | ml-kem-768 | Decapsulate a ciphertext using the derived ML-KEM-768 private key. Returns `{"shared_secret":"<hex>","algorithm":"ml-kem-768"}`. |
+| `derive_shared_secret` | x25519 | ECDH key agreement. Returns `{"shared_secret":"<hex>","algorithm":"x25519"}`. |
+| `get_public_key` | all algorithms | Returns the public key for the specified algorithm+index. |
+
+**General encryption verbs** (use `curve` parameter to select encryption method):
+
+| Verb | `curve` value | Description |
+|---|---|---|
+| `encrypt` | `otp` | One-time pad encryption (requires `--otp-pad-dir` + `--otp-pad`). Returns ASCII-armored or binary ciphertext. |
+| `decrypt` | `otp` | One-time pad decryption. Returns plaintext (base64). |
+| `encrypt` | `secp256k1` | NIP-44 (default) or NIP-04 encryption. Params: `[peer_pubkey, message, {nip_version: 4\|44}]`. |
+| `decrypt` | `secp256k1` | NIP-44 (default) or NIP-04 decryption. Params: `[peer_pubkey, ciphertext, {nip_version: 4\|44}]`. |
+| `encrypt` | `x25519` | ECDH + symmetric encryption (not yet implemented — use `derive_shared_secret` + your own cipher). |
+| `encrypt` | `ml-kem-768` | KEM-based hybrid encryption (not yet implemented — use `encapsulate`/`decapsulate` + your own cipher). |
+
+**OTP verb aliases** (also available, same as `encrypt`/`decrypt` with `curve: "otp"`):
+
+| Verb | Description |
+|---|---|
+| `otp_encrypt` | Encrypt plaintext (base64) with the bound OTP pad. Returns ASCII-armored or binary ciphertext. |
+| `otp_decrypt` | Decrypt ciphertext with the bound OTP pad. Returns plaintext (base64). |
+
+See [`plans/otp_nostr_integration.md`](plans/otp_nostr_integration.md) for the full OTP design.
+
+Example `sign` request (algorithm-based):
+
+```jsonc
+{ "id": "6", "method": "sign", "params": ["<message_hex>", { "algorithm": "ed25519", "index": 0 }] }
+```
+
+Example `otp_encrypt` request:
+
+```jsonc
+{ "id": "7", "method": "otp_encrypt", "params": ["<plaintext_base64>", { "encoding": "ascii" }] }
+```
+
+### `mine_event` — NIP-13 Proof-of-Work
+
+Mines proof-of-work (adds a `nonce` tag per NIP-13) and signs the event in one step. The mining runs in a detached thread so the server stays responsive.
+
+**Parameters (in options object):**
+
+| Option | Required | Default | Description |
+|--------|----------|---------|-------------|
+| `difficulty` | One of difficulty/timeout | 0 (no target) | Target leading zero bits. Stops early if reached. |
+| `timeout_sec` | One of difficulty/timeout | 600 (safety) | Time budget in seconds. Always returns best result found. |
+| `threads` | No | 1 | Number of mining threads (max 32). |
+
+At least one of `difficulty` or `timeout_sec` must be specified. If both are given, mining stops when either condition is met. The response always includes the best event found — timeout is not an error.
+
+**Response format:**
+
+```json
+{
+  "id": "5",
+  "result": {
+    "event": "<signed event JSON with nonce tag>",
+    "achieved_difficulty": 18,
+    "target_difficulty": 20,
+    "target_reached": false,
+    "elapsed_sec": 30,
+    "attempts": 4523456
+  }
+}
+```
+
+**Error codes:**
+
+- `1007` — `no_termination_condition` (neither difficulty nor timeout_sec specified)
+- `1008` — `mining_failed` (internal error)
 
 Selector resolution order:
 
@@ -208,16 +445,56 @@ Representative error codes:
 - `approval_denied`
 - `internal_error`
 
-## 6. Purpose and curve enforcement
+## 6. Purpose and curve enforcement (role-based API)
 
 Selector resolution chooses *which* role. Enforcement decides *whether the requested method is valid* for that role.
 
-Example:
+**Note:** The algorithm-based API (§4c) bypasses purpose/curve enforcement entirely — the caller specifies the algorithm directly, and the dispatcher derives the key on demand. Purpose values are only used by the role-based API for enforcement.
+
+### 6.1 Purpose values (role-based API only)
+
+| Purpose | Description |
+|---|---|
+| `nostr` | Nostr identities (secp256k1, NIP-06) |
+| `bitcoin` | Bitcoin key trees (secp256k1, BIP-44) |
+| `ssh` | SSH signing keys (ed25519) |
+| `age` | age-style encryption identities (x25519) |
+| `fips` | FIPS mesh/service identities |
+| `pq-sig` | Post-quantum signatures (ML-DSA-65, SLH-DSA-128s) |
+| `pq-kem` | Post-quantum key encapsulation (ML-KEM-768) |
+
+### 6.2 Curve values
+
+| Curve | Algorithms |
+|---|---|
+| `secp256k1` | ECDSA/Schnorr for Nostr, Bitcoin |
+| `ed25519` | Ed25519 for SSH signatures |
+| `x25519` | X25519 for key agreement (age) |
+| `ml-dsa-65` | ML-DSA-65 (FIPS 204, lattice-based PQ signatures) |
+| `slh-dsa-128s` | SLH-DSA-128s (FIPS 205, hash-based PQ signatures) |
+| `ml-kem-768` | ML-KEM-768 (FIPS 203, lattice-based PQ KEM) |
+
+### 6.3 Enforcement matrix (role-based API)
+
+| Verb | Required purpose | Required curve |
+|---|---|---|
+| `sign_event` | `nostr` | `secp256k1` |
+| `mine_event` | `nostr` | `secp256k1` |
+| `nip04_encrypt` / `nip04_decrypt` | `nostr` | `secp256k1` |
+| `nip44_encrypt` / `nip44_decrypt` | `nostr` | `secp256k1` |
+| `get_public_key` | any | any (must match role's declared curve) |
+| `sign_data` / `ssh_sign` | `ssh` or `pq-sig` | `ed25519`, `ml-dsa-65`, or `slh-dsa-128s` |
+| `verify_signature` | `ssh` or `pq-sig` | `ed25519`, `ml-dsa-65`, or `slh-dsa-128s` |
+| `kem_encapsulate` / `kem_decapsulate` | `pq-kem` | `ml-kem-768` |
+
+The algorithm-based API (§4c) does not use this matrix — the caller specifies the algorithm directly, and enforcement is based on the verb+algorithm combination (see [§4c.6](#4c6-enforcement-matrix)).
+
+Example (role-based):
 
 - `sign_event` requires `purpose="nostr"` and `curve="secp256k1"`.
 - If caller selects a Bitcoin-role key for `sign_event`, request fails with `purpose_mismatch`.
 
-This prevents cross-protocol misuse inside one mnemonic-rooted signer process.
+This prevents cross-protocol misuse inside one mnemonic-rooted signer process. Fail-closed: any unlisted `(verb, purpose, curve)` combination is rejected.
 
 ## 7. Transport
 
@@ -246,10 +523,70 @@ Discovery:
 - `nsigner list` enumerates currently bound `nsigner_*` abstract sockets by reading `/proc/net/unix`.
 - `nsigner --listen stdio` runs one framed JSON-RPC request/response over stdin/stdout.
 - `nsigner --listen qrexec` is the same stdio framing mode, but caller identity can be derived from `QREXEC_REMOTE_DOMAIN` (displayed as `qubes:<source-vm>`).
-- `nsigner --listen tcp:IPv4:PORT` or `tcp:[IPv6]:PORT` enables TCP listening for non-AF_UNIX clients (for example `tcp:127.0.0.1:8080`, `tcp:[::]:8080`, or `tcp:[fd00::1234]:8080`).
+- `nsigner --listen tcp:IPv4:PORT` or `tcp:[IPv6]:PORT` enables FIPS/TCP listening for non-AF_UNIX clients (for example `tcp:127.0.0.1:11111`, `tcp:[::]:11111`, or `tcp:[fd00::1234]:11111`). Uses framed JSON protocol (not HTTP).
+- `nsigner --listen http:HOST:PORT` enables HTTP listening for curl-friendly access (for example `http:127.0.0.1:11111`). Uses standard HTTP POST with JSON body — no custom framing. CORS headers included for browser access. Defaults to localhost; pass `http:0.0.0.0:PORT` to expose externally.
 - `nsigner bridge --to <socket-name>` is a stateless relay for Qubes qrexec: reads one framed request from stdin, forwards it to a persistent signer's abstract unix socket, and relays the response to stdout. Used as the `qubes.NsignerRpc` service entrypoint. See [§8.3](#83-qubes-os-qube) and [`plans/qrexec_persistent_bridge.md`](plans/qrexec_persistent_bridge.md).
 - `--bridge-source-trusted` (unix listener only): marks the socket as a trusted bridge endpoint. Each connection sends a framed `{"qrexec_source":"<vm>"}` preamble before the request, and the caller identity is composed as `qubes:<vm>` — matching the native qrexec identity path. This enables a persistent signer (mnemonic in mlock'd RAM) to receive qrexec-routed requests without spawning a fresh process per call.
 
+#### curl examples (HTTP mode)
+
+Start the signer in HTTP mode:
+```bash
+nsigner --listen http:127.0.0.1:11111 --allow-all
+```
+
+Get a public key:
+```bash
+curl -s -X POST http://127.0.0.1:11111/ -H 'Content-Type: application/json' \
+  -d '{"id":"1","method":"get_public_key","params":[{"role":"main"}]}'
+```
+
+Sign a Nostr event:
+```bash
+curl -s -X POST http://127.0.0.1:11111/ -H 'Content-Type: application/json' \
+  -d '{"id":"1","method":"sign_event","params":[{"pubkey":"...","created_at":1234567890,"kind":1,"tags":[],"content":"hello"}]}'
+```
+
+General encrypt (OTP, requires `--otp-pad-dir` and `--otp-pad`):
+```bash
+curl -s -X POST http://127.0.0.1:11111/ -H 'Content-Type: application/json' \
+  -d '{"id":"1","method":"encrypt","params":["SGVsbG8sIE9UUCB3b3JsZCE=",{"curve":"otp","encoding":"ascii"}]}'
+```
+
+General encrypt (NIP-44, secp256k1):
+```bash
+curl -s -X POST http://127.0.0.1:11111/ -H 'Content-Type: application/json' \
+  -d '{"id":"1","method":"encrypt","params":["<peer_pubkey_hex>","Hello!",{"role":"main"}]}'
+```
+
+General decrypt (OTP):
+```bash
+curl -s -X POST http://127.0.0.1:11111/ -H 'Content-Type: application/json' \
+  -d '{"id":"1","method":"decrypt","params":["-----BEGIN OTP MESSAGE-----...",{"curve":"otp","encoding":"ascii"}]}'
+```
+
+OTP verb aliases (same as encrypt/decrypt with curve=otp):
+```bash
+curl -s -X POST http://127.0.0.1:11111/ -H 'Content-Type: application/json' \
+  -d '{"id":"1","method":"otp_encrypt","params":["SGVsbG8sIE9UUCB3b3JsZCE=",{"encoding":"ascii"}]}'
+```
+
+#### Unix socket examples (framed mode)
+
+```bash
+# Get public key
+nsigner --socket-name nsigner client '{"id":"1","method":"get_public_key","params":[{"role":"main"}]}'
+
+# Sign event
+nsigner --socket-name nsigner client '{"id":"1","method":"sign_event","params":[{"pubkey":"...","created_at":1234567890,"kind":1,"tags":[],"content":"hello"}]}'
+
+# Encrypt (OTP)
+nsigner --socket-name nsigner client '{"id":"1","method":"encrypt","params":["SGVsbG8=",{"curve":"otp","encoding":"ascii"}]}'
+
+# Encrypt (NIP-44)
+nsigner --socket-name nsigner client '{"id":"1","method":"encrypt","params":["<peer_pubkey>","Hello!",{"role":"main"}]}'
+```
+
 ### 7.2 ESP32 MCU: TinyUSB composite (CDC + WebUSB)
 
 On Feather S3 TFT, MCU targets run the same core signer modules behind a TinyUSB composite transport:
@@ -287,9 +624,11 @@ MCU target reuses mnemonic/role/selector/enforcement/dispatcher core and swaps t
 
 Qubes deployment runs `n_signer` in a dedicated signer qube (e.g. `nostr_signer`) as a foreground process under explicit user session control. The mnemonic lives only in mlock'd RAM in that qube — a compromised agent in a caller qube cannot read it (hypervisor-enforced memory isolation).
 
-Two transport paths are supported:
+Three transport paths are supported:
 
-**FIPS/TCP** — the signer listens on `tcp:[::]:8080` and FIPS carries traffic between qubes as an IPv6 mesh substrate. See [`documents/FIPS_DEPLOYMENT.md`](documents/FIPS_DEPLOYMENT.md).
+**FIPS/TCP** — the signer listens on `tcp:[::]:11111` and FIPS carries traffic between qubes as an IPv6 mesh substrate. Uses framed JSON protocol. See [`documents/FIPS_DEPLOYMENT.md`](documents/FIPS_DEPLOYMENT.md).
+
+**HTTP** — the signer listens on `http:127.0.0.1:11111` for curl-friendly access within the same qube. Uses standard HTTP POST with JSON body. No auth envelopes required (relies on localhost binding + policy/approval prompts). Add `--listen http:127.0.0.1:11111` or select option 4 in the interactive transport menu.
 
 **Qubes qrexec bridge** (recommended for no-network deployments) — a persistent signer listens on an abstract unix socket, and a stateless `nsigner bridge` relay (the `qubes.NsignerRpc` qrexec service) forwards one request per qrexec invocation. No network, no FIPS — pure intra-host IPC. Caller identity is `qubes:<source-vm>` (from `QREXEC_REMOTE_DOMAIN`), relayed via a trusted preamble. See [`plans/qrexec_persistent_bridge.md`](plans/qrexec_persistent_bridge.md) for the full design.
 
@@ -351,10 +690,22 @@ Generic stdio transport mode (single framed request over stdin/stdout):
 nsigner --listen stdio
 ```
 
-TCP transport mode (no TUI; serves requests until terminated):
+FIPS/TCP transport mode (framed JSON, no TUI; serves requests until terminated):
 
 ```bash
-nsigner --listen tcp:[::]:8080
+nsigner --listen tcp:[::]:11111
+```
+
+HTTP transport mode (curl-friendly, no TUI; serves requests until terminated):
+
+```bash
+nsigner --listen http:127.0.0.1:11111
+```
+
+With OTP pad bound (auto-detects pads on USB drives in interactive mode):
+
+```bash
+nsigner --listen http:127.0.0.1:11111 --otp-pad-dir /media/user/Music/pads --otp-pad 333e9902db839d9d --allow-all
 ```
 
 Qrexec bridge mode (stateless relay to a persistent signer's unix socket; used as the `qubes.NsignerRpc` service):
@@ -446,15 +797,19 @@ Static build:
 
 ## 11. Implemented adjuncts and future work
 
-### Implemented PoC
+### Implemented features
 
+- **HTTP listener mode (`--listen http:HOST:PORT`).** Curl-friendly HTTP POST with JSON body. CORS headers included. See [§7.1](#71-linux-desktop-abstract-namespace-unix-socket) for curl examples.
+- **OTP one-time pad encryption (`otp_encrypt` / `otp_decrypt` verbs).** Information-theoretically secure encryption using one-time pads from the [`otp`](../otp) project. Pad material on USB drive, auto-detected at startup. See [`plans/otp_nostr_integration.md`](plans/otp_nostr_integration.md).
+- **Algorithm-based API (`sign`, `verify`, `encapsulate`, `decapsulate`, `derive_shared_secret`).** Caller specifies algorithm + index, no role needed. See [§4c](#4c-algorithm-based-api).
 - **MCU / USB signer (Feather ESP32-S3 Reverse TFT).** Working PoC in [`firmware/feather_s3_tft`](firmware/feather_s3_tft). Single TinyUSB composite USB device exposes both CDC-ACM and WebUSB Vendor interfaces. Same dispatcher serves both transports with auth envelope verification, on-device TFT prompts, and physical button approval. See [`firmware/README.md`](firmware/README.md) and [`plans/feather_tinyusb_composite.md`](plans/feather_tinyusb_composite.md).
 
 ### Future work (deferred)
 
 These items are designed and worth doing, but are not in the current implementation scope. They are listed here so they are not lost.
 
-- **`--listen http:[addr]:port` mode.** Today the TCP listener speaks 4-byte big-endian length-prefixed framed JSON-RPC, which is correct for low-overhead local IPC but is not directly reachable from web browsers (`fetch`, `XMLHttpRequest`, `curl`). A small additional listener that wraps the same dispatcher in minimal HTTP/1.1 (`POST /rpc`, `Content-Type: application/json`, `Content-Length`-framed body, JSON response) would let standard HTTP clients talk to `nsigner` without any custom framing code. The existing auth envelope (`kind:27235`) and JSON-RPC contract are unchanged; only the outer framing differs. CORS allow on the response would let browser extensions and (with TLS) HTTPS pages reach a remote `nsigner` over FIPS or any other carrier. See the discussion in [`documents/FIPS_DEPLOYMENT.md`](documents/FIPS_DEPLOYMENT.md) section 9 ("Next hardening steps").
+- **HTTPS / WSS (TLS) listener modes.** `--listen https:HOST:PORT` and `--listen wss:HOST:PORT` with `--tls-cert` / `--tls-key`. See [`plans/http_wss_listener.md`](plans/http_wss_listener.md).
+- **WebSocket listener mode (`--listen ws:HOST:PORT`).** For browser access with JSON text frames. See [`plans/http_wss_listener.md`](plans/http_wss_listener.md).
 - **NIP-46 bunker / relay transport.** Tracked in [`plans/nip46_bunker_mode.md`](plans/nip46_bunker_mode.md).
 - **Browser extension.** Tracked in [`plans/nsigner_browser_extension.md`](plans/nsigner_browser_extension.md). NIP-07 surface forwarding to a running `nsigner` instance.
 
@@ -471,8 +826,17 @@ These items are designed and worth doing, but are not in the current implementat
 - [`examples/get_pubkey_tcp.c`](examples/get_pubkey_tcp.c): C caller example using TCP transport with auth envelope
 - [`plans/nsigner.md`](plans/nsigner.md): implementation plan and sequencing
 - [`plans/seed_phrase_uses.md`](plans/seed_phrase_uses.md): seed phrase domain/use catalog and caveats
+- [`plans/post_quantum_crypto.md`](plans/post_quantum_crypto.md): post-quantum and multi-algorithm crypto expansion plan (all 8 phases)
 - [`firmware/feather_s3_tft`](firmware/feather_s3_tft): Feather ESP32-S3 Reverse TFT firmware (TinyUSB composite CDC + WebUSB signer PoC)
 - [`plans/feather_tinyusb_composite.md`](plans/feather_tinyusb_composite.md): firmware Phase 7b plan and outcome (TinyUSB composite USB transport)
 - [`plans/nsigner_browser_extension.md`](plans/nsigner_browser_extension.md): browser extension exposing NIP-07 over `nsigner`
 - [`plans/nip46_bunker_mode.md`](plans/nip46_bunker_mode.md): deferred NIP-46 relay-mode signer transport
+- [`plans/otp_nostr_integration.md`](plans/otp_nostr_integration.md): OTP one-time pad integration plan and design
+- [`plans/http_wss_listener.md`](plans/http_wss_listener.md): HTTP/WS/WSS listener modes plan
+- [`libotppad/`](libotppad/libotppad.h): shared OTP pad format library (XOR, ASCII armor, binary .otp, Padmé padding, state files, checksum)
+- [`src/otp_pad.c`](src/otp_pad.c) / [`src/otp_pad.h`](src/otp_pad.h): OTP pad state management for n_signer
+- [`src/http_listener.c`](src/http_listener.c) / [`src/http_listener.h`](src/http_listener.h): minimal HTTP/1.1 parser for HTTP listener mode
+- [`tools/make_test_pad.c`](tools/make_test_pad.c): generate a test OTP pad on a USB drive
+- [`tools/otp_roundtrip_test.py`](tools/otp_roundtrip_test.py): end-to-end OTP encrypt/decrypt round-trip test
+- [`examples/otp_nostr_30078.py`](examples/otp_nostr_30078.py): example — encrypt with OTP, wrap in Nostr kind 30078 event, sign
 - [`firmware/README.md`](firmware/README.md): firmware-side notes for MCU transport/UI integration

client/README.md

@@ -36,6 +36,79 @@ for the full integration contract.
 The `nsigner ... client '<json>'` subcommand in [`src/main.c`](../src/main.c) is
 unaffected — it has its own raw framing pass-through and never used this directory.
 
+## Multi-Algorithm and Post-Quantum Verbs
+
+n_signer supports six algorithms: `secp256k1` (Nostr), `ed25519` (SSH),
+`x25519` (age/ECDH), `ml-dsa-65` (PQ signatures, FIPS 204), `slh-dsa-128s`
+(PQ hash-based signatures, FIPS 205), and `ml-kem-768` (PQ KEM, FIPS 203).
+
+Use `nsigner_client_call(client, "<verb>", params, &result)` with these verbs:
+
+| Verb | Algorithms | Description |
+|---|---|---|
+| `get_public_key` | all | Returns the role's public key (see format below) |
+| `sign_event` | secp256k1 | Sign a Nostr event (existing) |
+| `nip44_encrypt` / `nip44_decrypt` | secp256k1 | NIP-44 (existing) |
+| `nip04_encrypt` / `nip04_decrypt` | secp256k1 | NIP-04 (existing) |
+| `mine_event` | secp256k1 | NIP-13 PoW mining + sign (existing) |
+| `sign_data` | ed25519, ml-dsa-65, slh-dsa-128s | Sign arbitrary bytes (hex) |
+| `verify_signature` | ed25519, ml-dsa-65, slh-dsa-128s | Verify a signature against the role's pubkey |
+| `ssh_sign` | ed25519 | Sign an SSH authentication challenge |
+| `kem_encapsulate` | ml-kem-768 | Encapsulate with a peer's ML-KEM public key |
+| `kem_decapsulate` | ml-kem-768 | Decapsulate a ciphertext with the role's ML-KEM private key |
+
+### Algorithm-based API (new)
+
+In addition to the role-based verbs above, the signer supports algorithm-based verbs where the caller specifies `algorithm` and `index` directly, without needing a role:
+
+| Verb | Algorithms | Description |
+|---|---|---|
+| `sign` | secp256k1, ed25519, ml-dsa-65, slh-dsa-128s | Sign arbitrary bytes (hex) |
+| `verify` | secp256k1, ed25519, ml-dsa-65, slh-dsa-128s | Verify a signature |
+| `encapsulate` | ml-kem-768 | KEM encapsulation with peer's public key |
+| `decapsulate` | ml-kem-768 | KEM decapsulation with derived private key |
+| `derive_shared_secret` | x25519 | ECDH key agreement |
+| `get_public_key` (with `algorithm`) | all | Get public key for a derived key |
+
+Example: `nsigner_client_call(client, "sign", "[\"68656c6c6f\",{\"algorithm\":\"ed25519\",\"index\":0}]", &result)`
+
+For secp256k1, the optional `scheme` parameter selects `"schnorr"` (default) or `"ecdsa"`.
+
+Old verbs (`sign_data`, `ssh_sign`, `verify_signature`, `kem_encapsulate`, `kem_decapsulate`) also accept the `algorithm` parameter and map to the new verbs. Without `algorithm`, they use the role-based path (backward compatible).
+
+### `get_public_key` response format
+
+- **secp256k1 (backward compatible):** `result` is a plain hex string
+  (`cJSON_IsString(result)` is true, 64 hex chars).
+- **secp256k1 with `{"format":"structured"}` option:** `result` is a JSON
+  string containing `{"algorithm":"secp256k1","public_key":"<hex>","key_id":"<16 hex>"}`.
+- **All other algorithms:** `result` is always a JSON string containing
+  `{"algorithm":"<alg>","public_key":"<hex>","key_id":"<16 hex>"}`.
+
+Clients should parse the `result` string with `cJSON_Parse` to extract the
+`algorithm`, `public_key`, and `key_id` fields for non-secp256k1 algorithms.
+
+### Key sizes
+
+| Algorithm | Pub key | Priv key | Signature | Ciphertext | Shared secret |
+|---|---|---|---|---|---|
+| secp256k1 | 32 B | 32 B | 64 B | — | — |
+| ed25519 | 32 B | 32 B | 64 B | — | — |
+| x25519 | 32 B | 32 B | — | — | 32 B |
+| ML-DSA-65 | 1952 B | 4032 B | 3309 B | — | — |
+| SLH-DSA-128s | 32 B | 64 B | 7856 B | — | — |
+| ML-KEM-768 | 1184 B | 2400 B | — | 1088 B | 32 B |
+
+### Example clients
+
+- [`examples/pq_sign_example.c`](../examples/pq_sign_example.c) — ML-DSA-65 sign
+- [`examples/pq_kem_example.c`](../examples/pq_kem_example.c) — ML-KEM-768 encaps/decaps
+- [`examples/ssh_sign_example.c`](../examples/ssh_sign_example.c) — ed25519 SSH sign
+
+See [`documents/CLIENT_IMPLEMENTATION.md`](../documents/CLIENT_IMPLEMENTATION.md)
+section 11 for the full multi-algorithm specification, derivation paths, and
+example request/response transcripts.
+
 ## Why
 
 Per [`plans/nsigner_integration_plan.md`](../resources/nostr_core_lib/plans/nsigner_integration_plan.md)

client/demo_c99.c

@@ -0,0 +1,322 @@
+/*
+ * demo_c99.c — comprehensive C99 demo for connecting to a running n_signer
+ * via Qubes qrexec and performing all three core operations:
+ *
+ *   1. get_public_key  — retrieve a Nostr public key by nostr_index
+ *   2. sign_event      — sign a Nostr event (kind 1 text note)
+ *   3. nip44_encrypt   — encrypt a message to a peer (and decrypt it back)
+ *
+ * Note: mine_event (NIP-13 PoW) is also available via the JSON-RPC interface.
+ * See demo_javascript.js and demo_python.py for mine_event usage examples.
+ * The high-level nostr_signer API does not yet wrap mine_event.
+ *
+ * This uses the high-level nostr_signer API from nostr_core_lib:
+ *   - nostr_signer_nsigner_qrexec()     — qrexec transport (no network)
+ *   - nostr_signer_nsigner_set_nostr_index() — select key by NIP-06 index
+ *   - nostr_signer_get_public_key()     — get pubkey
+ *   - nostr_signer_sign_event()         — sign an event
+ *   - nostr_signer_nip44_encrypt()      — encrypt
+ *   - nostr_signer_nip44_decrypt()      — decrypt
+ *
+ * Prerequisites:
+ *   - n_signer running in the target qube with --bridge-source-trusted
+ *   - qubes.NsignerRpc service installed in the target qube
+ *   - dom0 qrexec policy allowing this qube to call the service
+ *
+ * Build (from n_signer repo root):
+ *   make examples
+ *
+ * Usage:
+ *   ./build/demo_c99 <target_qube> [nostr_index]
+ *   ./build/demo_c99 nostr_signer 1
+ *
+ * If no nostr_index is given, defaults to 0.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <signal.h>
+
+#include "nostr_common.h"
+#include "nostr_signer.h"
+#include "nip019.h"
+#include "../cjson/cJSON.h"
+
+/* Helper: convert 32-byte hex pubkey to bech32 npub */
+static int hex_to_npub(const char *hex, char *out_npub, size_t out_sz) {
+    unsigned char bytes[32];
+    int i;
+
+    if (strlen(hex) != 64) {
+        return -1;
+    }
+
+    for (i = 0; i < 32; i++) {
+        unsigned int byte;
+        if (sscanf(hex + 2 * i, "%2x", &byte) != 1) {
+            return -1;
+        }
+        bytes[i] = (unsigned char)byte;
+    }
+
+    return nostr_key_to_bech32(bytes, "npub", out_npub);
+}
+
+/* Helper: print an error with a human-readable description */
+static void print_error(const char *operation, int rc) {
+    const char *desc = "unknown error";
+    switch (rc) {
+        case NOSTR_ERROR_INVALID_INPUT:
+            desc = "invalid input";
+            break;
+        case NOSTR_ERROR_CRYPTO_FAILED:
+            desc = "crypto operation failed";
+            break;
+        case NOSTR_ERROR_IO_FAILED:
+            desc = "I/O failed (transport error)";
+            break;
+        case NOSTR_ERROR_NETWORK_FAILED:
+            desc = "network failed";
+            break;
+        case NOSTR_ERROR_NSIGNER_POLICY_DENIED:
+            desc = "policy denied (caller not approved at signer terminal)";
+            break;
+        case NOSTR_ERROR_NSIGNER_INDEX_NOT_ALLOWED:
+            desc = "index not in signer's whitelist";
+            break;
+        default:
+            /* Try to print the numeric code */
+            fprintf(stderr, "  %s failed: error code %d\n", operation, rc);
+            return;
+    }
+    fprintf(stderr, "  %s failed: %s (code %d)\n", operation, desc, rc);
+}
+
+/*
+ * Demo 1: Get a public key by nostr_index.
+ * Returns the hex pubkey in `out_hex` (must be 65 bytes).
+ */
+static int demo_get_public_key(nostr_signer_t *signer, int nostr_index,
+                                char *out_hex, size_t hex_sz) {
+    char npub[128];
+    int rc;
+
+    printf("\n=== Demo 1: get_public_key (nostr_index=%d) ===\n", nostr_index);
+
+    rc = nostr_signer_get_public_key(signer, out_hex);
+    if (rc != NOSTR_SUCCESS) {
+        print_error("get_public_key", rc);
+        return rc;
+    }
+
+    if (hex_to_npub(out_hex, npub, sizeof(npub)) == 0) {
+        printf("  pubkey hex: %s\n", out_hex);
+        printf("  npub:       %s\n", npub);
+    } else {
+        printf("  pubkey hex: %s\n", out_hex);
+        printf("  (npub conversion failed)\n");
+    }
+
+    return NOSTR_SUCCESS;
+}
+
+/*
+ * Demo 2: Sign a Nostr event (kind 1 text note).
+ * The signed event JSON is printed.
+ */
+static int demo_sign_event(nostr_signer_t *signer, const char *pubkey_hex) {
+    cJSON *unsigned_event = NULL;
+    cJSON *signed_event = NULL;
+    char *signed_json = NULL;
+    int rc;
+
+    printf("\n=== Demo 2: sign_event (kind 1 text note) ===\n");
+
+    /* Build an unsigned Nostr event (kind 1 text note) */
+    unsigned_event = cJSON_CreateObject();
+    if (unsigned_event == NULL) {
+        fprintf(stderr, "  failed to create event JSON\n");
+        return NOSTR_ERROR_MEMORY_FAILED;
+    }
+
+    cJSON_AddNumberToObject(unsigned_event, "kind", 1);
+    cJSON_AddStringToObject(unsigned_event, "content", "Hello from n_signer C99 demo!");
+    cJSON_AddNumberToObject(unsigned_event, "created_at", (int)time(NULL));
+
+    /* tags: empty array */
+    cJSON_AddItemToObject(unsigned_event, "tags", cJSON_CreateArray());
+
+    /* pubkey: the signer will fill this in, but we include it for completeness */
+    cJSON_AddStringToObject(unsigned_event, "pubkey", pubkey_hex);
+
+    printf("  Unsigned event:\n");
+    {
+        char *tmp = cJSON_PrintUnformatted(unsigned_event);
+        if (tmp) {
+            printf("    %s\n", tmp);
+            free(tmp);
+        }
+    }
+
+    /* Sign it */
+    rc = nostr_signer_sign_event(signer, unsigned_event, &signed_event);
+    if (rc != NOSTR_SUCCESS) {
+        print_error("sign_event", rc);
+        cJSON_Delete(unsigned_event);
+        return rc;
+    }
+
+    /* Print the signed event */
+    signed_json = cJSON_Print(signed_event);
+    if (signed_json) {
+        printf("  Signed event:\n");
+        printf("    %s\n", signed_json);
+        free(signed_json);
+    }
+
+    /* Extract and show the signature and event id */
+    {
+        cJSON *id = cJSON_GetObjectItemCaseSensitive(signed_event, "id");
+        cJSON *sig = cJSON_GetObjectItemCaseSensitive(signed_event, "sig");
+        if (id && cJSON_IsString(id)) {
+            printf("  event id: %s\n", id->valuestring);
+        }
+        if (sig && cJSON_IsString(sig)) {
+            printf("  signature: %s\n", sig->valuestring);
+        }
+    }
+
+    cJSON_Delete(signed_event);
+    cJSON_Delete(unsigned_event);
+    return NOSTR_SUCCESS;
+}
+
+/*
+ * Demo 3: NIP-44 encrypt and decrypt.
+ * Encrypts a message to ourselves (using our own pubkey as the peer),
+ * then decrypts it to verify round-trip.
+ */
+static int demo_nip44(nostr_signer_t *signer, const char *pubkey_hex) {
+    const char *plaintext = "Secret message from n_signer C99 demo!";
+    char *ciphertext = NULL;
+    char *decrypted = NULL;
+    int rc;
+
+    printf("\n=== Demo 3: nip44_encrypt / nip44_decrypt ===\n");
+    printf("  plaintext:  \"%s\"\n", plaintext);
+    printf("  peer pubkey: %s (self)\n", pubkey_hex);
+
+    /* Encrypt */
+    rc = nostr_signer_nip44_encrypt(signer, pubkey_hex, plaintext, &ciphertext);
+    if (rc != NOSTR_SUCCESS) {
+        print_error("nip44_encrypt", rc);
+        return rc;
+    }
+
+    printf("  ciphertext: %s\n", ciphertext);
+
+    /* Decrypt (using our own pubkey as the sender) */
+    rc = nostr_signer_nip44_decrypt(signer, pubkey_hex, ciphertext, &decrypted);
+    if (rc != NOSTR_SUCCESS) {
+        print_error("nip44_decrypt", rc);
+        free(ciphertext);
+        return rc;
+    }
+
+    printf("  decrypted:  \"%s\"\n", decrypted);
+
+    /* Verify round-trip */
+    if (strcmp(plaintext, decrypted) == 0) {
+        printf("  ✓ Round-trip verified: plaintext matches decrypted\n");
+    } else {
+        printf("  ✗ Round-trip FAILED: plaintext does not match decrypted\n");
+        rc = NOSTR_ERROR_CRYPTO_FAILED;
+    }
+
+    free(ciphertext);
+    free(decrypted);
+    return rc;
+}
+
+int main(int argc, char **argv) {
+    const char *target_qube;
+    const char *service_name = "qubes.NsignerRpc";
+    int nostr_index = 0;
+    nostr_signer_t *signer = NULL;
+    char pubkey_hex[65];
+    int rc;
+
+    /* Ignore SIGPIPE — qrexec subprocess may close pipes abruptly */
+    (void)signal(SIGPIPE, SIG_IGN);
+
+    if (argc < 2) {
+        fprintf(stderr, "Usage: %s <target_qube> [nostr_index]\n", argv[0]);
+        fprintf(stderr, "Example: %s nostr_signer 1\n", argv[0]);
+        return 1;
+    }
+    target_qube = argv[1];
+    if (argc > 2) {
+        nostr_index = atoi(argv[2]);
+    }
+
+    /* Initialize the crypto subsystem */
+    if (nostr_init() != NOSTR_SUCCESS) {
+        fprintf(stderr, "Failed to initialize crypto subsystem\n");
+        return 1;
+    }
+
+    printf("=== n_signer C99 Demo ===\n");
+    printf("Target qube: %s\n", target_qube);
+    printf("Service:     %s\n", service_name);
+    printf("nostr_index: %d\n", nostr_index);
+    printf("\n");
+
+    /* Create a high-level signer backed by qrexec transport */
+    printf("Connecting to n_signer via qrexec...\n");
+    signer = nostr_signer_nsigner_qrexec(target_qube, service_name, NULL, 30000);
+    if (signer == NULL) {
+        fprintf(stderr, "Failed to create qrexec signer.\n");
+        fprintf(stderr, "Is qrexec-client-vm available? Is the service installed?\n");
+        nostr_cleanup();
+        return 1;
+    }
+    printf("Connected.\n");
+
+    /* Select key by nostr_index (NIP-06 m/44'/1237'/N'/0/0) */
+    rc = nostr_signer_nsigner_set_nostr_index(signer, nostr_index);
+    if (rc != NOSTR_SUCCESS) {
+        print_error("set_nostr_index", rc);
+        nostr_signer_free(signer);
+        nostr_cleanup();
+        return 1;
+    }
+
+    /* Demo 1: Get public key */
+    rc = demo_get_public_key(signer, nostr_index, pubkey_hex, sizeof(pubkey_hex));
+    if (rc != NOSTR_SUCCESS) {
+        goto cleanup;
+    }
+
+    /* Demo 2: Sign an event */
+    rc = demo_sign_event(signer, pubkey_hex);
+    if (rc != NOSTR_SUCCESS) {
+        goto cleanup;
+    }
+
+    /* Demo 3: NIP-44 encrypt/decrypt */
+    rc = demo_nip44(signer, pubkey_hex);
+
+cleanup:
+    printf("\n=== Summary ===\n");
+    if (rc == NOSTR_SUCCESS) {
+        printf("All demos completed successfully.\n");
+    } else {
+        printf("Demo failed with error code %d.\n", rc);
+    }
+
+    nostr_signer_free(signer);
+    nostr_cleanup();
+    return (rc == NOSTR_SUCCESS) ? 0 : 1;
+}

client/demo_javascript.js

@@ -0,0 +1,268 @@
+#!/usr/bin/env node
+/**
+ * demo_javascript.js — comprehensive JavaScript demo for connecting to a
+ * running n_signer via Qubes qrexec and performing all three core operations:
+ *
+ *   1. get_public_key  — retrieve a Nostr public key by nostr_index
+ *   2. sign_event      — sign a Nostr event (kind 1 text note)
+ *   3. nip44_encrypt   — encrypt a message to a peer (and decrypt it back)
+ *
+ * Uses qrexec-client-vm (Qubes OS inter-qube IPC). No auth envelope needed —
+ * identity comes from QREXEC_REMOTE_DOMAIN on the server side.
+ *
+ * Prerequisites:
+ *   - n_signer running in the target qube with --bridge-source-trusted
+ *   - qubes.NsignerRpc service installed in the target qube
+ *   - dom0 qrexec policy allowing this qube to call the service
+ *   - nostr-tools and @noble/secp256k1 npm packages installed
+ *
+ * Install dependencies (from n_signer repo root):
+ *   npm install nostr-tools @noble/secp256k1
+ *
+ * Usage:
+ *   node client/demo_javascript.js <target_qube> [nostr_index]
+ *   node client/demo_javascript.js nostr_signer 1
+ *
+ * If no nostr_index is given, defaults to 0.
+ */
+
+const { spawn } = require("child_process");
+const crypto = require("crypto");
+const secp = require("@noble/secp256k1");
+const { nip19 } = require("nostr-tools");
+
+// @noble/secp256k1 v3 requires sync sha256/hmacSha256
+secp.hashes.sha256 = (msg) => new Uint8Array(crypto.createHash("sha256").update(msg).digest());
+secp.hashes.hmacSha256 = (key, msg) =>
+  new Uint8Array(crypto.createHmac("sha256", key).update(msg).digest());
+
+/**
+ * Call n_signer via qrexec. Sends one framed JSON-RPC request, receives one
+ * framed response. Each call spawns a fresh qrexec-client-vm process.
+ *
+ * Framing: 4-byte big-endian length prefix + JSON payload.
+ * No auth envelope needed for qrexec (identity from QREXEC_REMOTE_DOMAIN).
+ */
+function callNsigner(targetQube, request) {
+  return new Promise((resolve, reject) => {
+    const payload = Buffer.from(JSON.stringify(request), "utf8");
+    const header = Buffer.alloc(4);
+    header.writeUInt32BE(payload.length, 0);
+    const framed = Buffer.concat([header, payload]);
+
+    const proc = spawn("qrexec-client-vm", [targetQube, "qubes.NsignerRpc"], {
+      stdio: ["pipe", "pipe", "pipe"],
+    });
+
+    const stdoutChunks = [];
+    const stderrChunks = [];
+
+    proc.stdout.on("data", (chunk) => stdoutChunks.push(chunk));
+    proc.stderr.on("data", (chunk) => stderrChunks.push(chunk));
+
+    proc.on("error", (err) => {
+      reject(new Error(`failed to spawn qrexec-client-vm: ${err.message}`));
+    });
+
+    proc.on("close", (code) => {
+      if (code !== 0) {
+        const stderr = Buffer.concat(stderrChunks).toString("utf8");
+        reject(new Error(`qrexec-client-vm exited with code ${code}: ${stderr.trim()}`));
+        return;
+      }
+      const buf = Buffer.concat(stdoutChunks);
+      if (buf.length < 4) {
+        reject(new Error("short response (missing frame header)"));
+        return;
+      }
+      const len = buf.readUInt32BE(0);
+      const body = buf.subarray(4, 4 + len);
+      if (body.length !== len) {
+        reject(new Error(`short response payload: expected ${len}, got ${body.length}`));
+        return;
+      }
+      try {
+        resolve(JSON.parse(body.toString("utf8")));
+      } catch (e) {
+        reject(new Error(`failed to parse response: ${e.message}`));
+      }
+    });
+
+    proc.stdin.write(framed);
+    proc.stdin.end();
+  });
+}
+
+/**
+ * Demo 1: Get a public key by nostr_index.
+ */
+async function demoGetPublicKey(targetQube, nostrIndex) {
+  console.log(`\n=== Demo 1: get_public_key (nostr_index=${nostrIndex}) ===`);
+
+  const response = await callNsigner(targetQube, {
+    id: "1",
+    method: "get_public_key",
+    params: [{ nostr_index: nostrIndex }],
+  });
+
+  if (response.error) {
+    throw new Error(`get_public_key failed: ${JSON.stringify(response.error)}`);
+  }
+
+  const pubkeyHex = response.result;
+  const npub = nip19.npubEncode(pubkeyHex);
+  console.log(`  pubkey hex: ${pubkeyHex}`);
+  console.log(`  npub:       ${npub}`);
+  return pubkeyHex;
+}
+
+/**
+ * Demo 2: Sign a Nostr event (kind 1 text note).
+ */
+async function demoSignEvent(targetQube, nostrIndex, pubkeyHex) {
+  console.log("\n=== Demo 2: sign_event (kind 1 text note) ===");
+
+  const unsignedEvent = {
+    kind: 1,
+    content: "Hello from n_signer JavaScript demo!",
+    created_at: Math.floor(Date.now() / 1000),
+    tags: [],
+    pubkey: pubkeyHex,
+  };
+
+  console.log("  Unsigned event:");
+  console.log(`    ${JSON.stringify(unsignedEvent)}`);
+
+  const response = await callNsigner(targetQube, {
+    id: "2",
+    method: "sign_event",
+    params: [JSON.stringify(unsignedEvent), { nostr_index: nostrIndex }],
+  });
+
+  if (response.error) {
+    throw new Error(`sign_event failed: ${JSON.stringify(response.error)}`);
+  }
+
+  const signedEvent = JSON.parse(response.result);
+  console.log("  Signed event:");
+  console.log(`    ${JSON.stringify(signedEvent)}`);
+  console.log(`  event id: ${signedEvent.id}`);
+  console.log(`  signature: ${signedEvent.sig}`);
+  return signedEvent;
+}
+
+/**
+ * Demo 3: NIP-44 encrypt and decrypt.
+ * Encrypts a message to ourselves (using our own pubkey as the peer),
+ * then decrypts it to verify round-trip.
+ */
+async function demoNip44(targetQube, nostrIndex, pubkeyHex) {
+  const plaintext = "Secret message from n_signer JavaScript demo!";
+
+  console.log("\n=== Demo 3: nip44_encrypt / nip44_decrypt ===");
+  console.log(`  plaintext:  "${plaintext}"`);
+  console.log(`  peer pubkey: ${pubkeyHex} (self)`);
+
+  // Encrypt
+  const encResponse = await callNsigner(targetQube, {
+    id: "3",
+    method: "nip44_encrypt",
+    params: [pubkeyHex, plaintext, { nostr_index: nostrIndex }],
+  });
+
+  if (encResponse.error) {
+    throw new Error(`nip44_encrypt failed: ${JSON.stringify(encResponse.error)}`);
+  }
+
+  const ciphertext = encResponse.result;
+  console.log(`  ciphertext: ${ciphertext}`);
+
+  // Decrypt
+  const decResponse = await callNsigner(targetQube, {
+    id: "4",
+    method: "nip44_decrypt",
+    params: [pubkeyHex, ciphertext, { nostr_index: nostrIndex }],
+  });
+
+  if (decResponse.error) {
+    throw new Error(`nip44_decrypt failed: ${JSON.stringify(decResponse.error)}`);
+  }
+
+  const decrypted = decResponse.result;
+  console.log(`  decrypted:  "${decrypted}"`);
+
+  if (plaintext === decrypted) {
+    console.log("  ✓ Round-trip verified: plaintext matches decrypted");
+  } else {
+    throw new Error("Round-trip FAILED: plaintext does not match decrypted");
+  }
+}
+
+async function demoMineEvent(targetQube, nostrIndex) {
+  console.log("\n--- Demo 4: mine_event (NIP-13 Proof-of-Work) ---");
+
+  const event = {
+    kind: 1,
+    content: "Hello Nostr with PoW!",
+    tags: [],
+  };
+
+  console.log("  Mining with difficulty=4, threads=4, timeout_sec=30...");
+  const response = await callNsigner(targetQube, {
+    id: "5",
+    method: "mine_event",
+    params: [JSON.stringify(event), {
+      difficulty: 4,
+      threads: 4,
+      timeout_sec: 30,
+      nostr_index: nostrIndex,
+    }],
+  });
+
+  if (response.error) {
+    throw new Error(`mine_event failed: ${JSON.stringify(response.error)}`);
+  }
+
+  const result = JSON.parse(response.result);
+  console.log(`  achieved_difficulty: ${result.achieved_difficulty}`);
+  console.log(`  target_reached:      ${result.target_reached}`);
+  console.log(`  elapsed_sec:         ${result.elapsed_sec}`);
+  console.log(`  attempts:            ${result.attempts}`);
+
+  const minedEvent = JSON.parse(result.event);
+  console.log(`  event id:            ${minedEvent.id}`);
+  console.log(`  nonce tag:           ${JSON.stringify(minedEvent.tags[0])}`);
+
+  if (result.target_reached) {
+    console.log("  ✓ Target difficulty reached!");
+  } else {
+    console.log(`  (Target not reached, best effort: ${result.achieved_difficulty} bits)`);
+  }
+}
+
+async function main() {
+  const targetQube = process.argv[2] || "nostr_signer";
+  const nostrIndex = parseInt(process.argv[3] || "0", 10);
+
+  console.log("=== n_signer JavaScript Demo ===");
+  console.log(`Target qube: ${targetQube}`);
+  console.log(`Service:     qubes.NsignerRpc`);
+  console.log(`nostr_index: ${nostrIndex}`);
+  console.log("\nConnecting to n_signer via qrexec...");
+
+  try {
+    const pubkeyHex = await demoGetPublicKey(targetQube, nostrIndex);
+    await demoSignEvent(targetQube, nostrIndex, pubkeyHex);
+    await demoNip44(targetQube, nostrIndex, pubkeyHex);
+    await demoMineEvent(targetQube, nostrIndex);
+
+    console.log("\n=== Summary ===");
+    console.log("All demos completed successfully.");
+  } catch (e) {
+    console.error("\n=== Summary ===");
+    console.error(`Demo failed: ${e.message}`);
+    process.exit(1);
+  }
+}
+
+main();

client/demo_python.py

@@ -0,0 +1,296 @@
+#!/usr/bin/env python3
+"""
+demo_python.py — comprehensive Python demo for connecting to a running n_signer
+via Qubes qrexec and performing all three core operations:
+
+  1. get_public_key  — retrieve a Nostr public key by nostr_index
+  2. sign_event      — sign a Nostr event (kind 1 text note)
+  3. nip44_encrypt   — encrypt a message to a peer (and decrypt it back)
+
+Uses qrexec-client-vm (Qubes OS inter-qube IPC). No auth envelope needed —
+identity comes from QREXEC_REMOTE_DOMAIN on the server side.
+
+Prerequisites:
+  - n_signer running in the target qube with --bridge-source-trusted
+  - qubes.NsignerRpc service installed in the target qube
+  - dom0 qrexec policy allowing this qube to call the service
+  - Python 3 with no external dependencies (uses only stdlib)
+
+Usage:
+  python3 client/demo_python.py <target_qube> [nostr_index]
+  python3 client/demo_python.py nostr_signer 1
+
+If no nostr_index is given, defaults to 0.
+"""
+
+import json
+import struct
+import subprocess
+import sys
+import time
+
+
+# --- Bech32 encoder (NIP-19 npub conversion, no external dependencies) ---
+
+CHARSET = "qpzry9x8gf2tvdw0s3jn54khce6mua7l"
+
+
+def bech32_polymod(values):
+    generator = [0x3B6A57B2, 0x26508E6D, 0x1EA119FA, 0x3D4233DD, 0x2A1462B3]
+    chk = 1
+    for v in values:
+        b = chk >> 25
+        chk = (chk & 0x1FFFFFF) << 5 ^ v
+        for i in range(5):
+            chk ^= generator[i] if ((b >> i) & 1) else 0
+    return chk
+
+
+def bech32_hrp_expand(hrp):
+    return [ord(x) >> 5 for x in hrp] + [0] + [ord(x) & 31 for x in hrp]
+
+
+def bech32_create_checksum(hrp, data):
+    values = bech32_hrp_expand(hrp) + data
+    polymod = bech32_polymod(values + [0, 0, 0, 0, 0, 0]) ^ 1
+    return [(polymod >> 5 * (5 - i)) & 31 for i in range(6)]
+
+
+def bech32_encode(hrp, data):
+    combined = data + bech32_create_checksum(hrp, data)
+    return hrp + "1" + "".join([CHARSET[d] for d in combined])
+
+
+def convertbits(data, frombits, tobits, pad=True):
+    acc = 0
+    bits = 0
+    ret = []
+    maxv = (1 << tobits) - 1
+    max_acc = (1 << (frombits + tobits - 1)) - 1
+    for value in data:
+        acc = ((acc << frombits) | value) & max_acc
+        bits += frombits
+        while bits >= tobits:
+            bits -= tobits
+            ret.append((acc >> bits) & maxv)
+    if pad and bits:
+        ret.append((acc << (tobits - bits)) & maxv)
+    return ret
+
+
+def hex_to_npub(pubkey_hex):
+    """Convert a 32-byte hex pubkey to bech32 npub format (NIP-19)."""
+    pubkey_bytes = bytes.fromhex(pubkey_hex)
+    data = convertbits(pubkey_bytes, 8, 5)
+    return bech32_encode("npub", data)
+
+
+# --- n_signer qrexec client ---
+
+def call_nsigner(target_qube, request):
+    """
+    Call n_signer via qrexec. Sends one framed JSON-RPC request, receives one
+    framed response. Each call spawns a fresh qrexec-client-vm process.
+
+    Framing: 4-byte big-endian length prefix + JSON payload.
+    No auth envelope needed for qrexec (identity from QREXEC_REMOTE_DOMAIN).
+    """
+    payload = json.dumps(request, separators=(",", ":")).encode("utf-8")
+    frame = struct.pack(">I", len(payload)) + payload
+
+    proc = subprocess.Popen(
+        ["qrexec-client-vm", target_qube, "qubes.NsignerRpc"],
+        stdin=subprocess.PIPE,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+    )
+    out, err = proc.communicate(frame)
+
+    if proc.returncode != 0:
+        raise RuntimeError(
+            f"qrexec-client-vm exited with code {proc.returncode}: "
+            f"{err.decode('utf-8', 'replace').strip()}"
+        )
+
+    if len(out) < 4:
+        raise RuntimeError("short response (missing frame header)")
+
+    length = struct.unpack(">I", out[:4])[0]
+    body = out[4 : 4 + length]
+    if len(body) != length:
+        raise RuntimeError(
+            f"short response payload: expected {length}, got {len(body)}"
+        )
+
+    return json.loads(body.decode("utf-8"))
+
+
+# --- Demos ---
+
+def demo_get_public_key(target_qube, nostr_index):
+    """Demo 1: Get a public key by nostr_index."""
+    print(f"\n=== Demo 1: get_public_key (nostr_index={nostr_index}) ===")
+
+    response = call_nsigner(
+        target_qube,
+        {"id": "1", "method": "get_public_key", "params": [{"nostr_index": nostr_index}]},
+    )
+
+    if "error" in response:
+        raise RuntimeError(f"get_public_key failed: {json.dumps(response['error'])}")
+
+    pubkey_hex = response["result"]
+    npub = hex_to_npub(pubkey_hex)
+    print(f"  pubkey hex: {pubkey_hex}")
+    print(f"  npub:       {npub}")
+    return pubkey_hex
+
+
+def demo_sign_event(target_qube, nostr_index, pubkey_hex):
+    """Demo 2: Sign a Nostr event (kind 1 text note)."""
+    print("\n=== Demo 2: sign_event (kind 1 text note) ===")
+
+    unsigned_event = {
+        "kind": 1,
+        "content": "Hello from n_signer Python demo!",
+        "created_at": int(time.time()),
+        "tags": [],
+        "pubkey": pubkey_hex,
+    }
+
+    print("  Unsigned event:")
+    print(f"    {json.dumps(unsigned_event, separators=(',', ':'))}")
+
+    response = call_nsigner(
+        target_qube,
+        {
+            "id": "2",
+            "method": "sign_event",
+            "params": [json.dumps(unsigned_event, separators=(",", ":")), {"nostr_index": nostr_index}],
+        },
+    )
+
+    if "error" in response:
+        raise RuntimeError(f"sign_event failed: {json.dumps(response['error'])}")
+
+    signed_event = json.loads(response["result"])
+    print("  Signed event:")
+    print(f"    {json.dumps(signed_event, separators=(',', ':'))}")
+    print(f"  event id: {signed_event['id']}")
+    print(f"  signature: {signed_event['sig']}")
+    return signed_event
+
+
+def demo_nip44(target_qube, nostr_index, pubkey_hex):
+    """Demo 3: NIP-44 encrypt and decrypt."""
+    plaintext = "Secret message from n_signer Python demo!"
+
+    print("\n=== Demo 3: nip44_encrypt / nip44_decrypt ===")
+    print(f'  plaintext:  "{plaintext}"')
+    print(f"  peer pubkey: {pubkey_hex} (self)")
+
+    # Encrypt
+    enc_response = call_nsigner(
+        target_qube,
+        {
+            "id": "3",
+            "method": "nip44_encrypt",
+            "params": [pubkey_hex, plaintext, {"nostr_index": nostr_index}],
+        },
+    )
+
+    if "error" in enc_response:
+        raise RuntimeError(f"nip44_encrypt failed: {json.dumps(enc_response['error'])}")
+
+    ciphertext = enc_response["result"]
+    print(f"  ciphertext: {ciphertext}")
+
+    # Decrypt
+    dec_response = call_nsigner(
+        target_qube,
+        {
+            "id": "4",
+            "method": "nip44_decrypt",
+            "params": [pubkey_hex, ciphertext, {"nostr_index": nostr_index}],
+        },
+    )
+
+    if "error" in dec_response:
+        raise RuntimeError(f"nip44_decrypt failed: {json.dumps(dec_response['error'])}")
+
+    decrypted = dec_response["result"]
+    print(f'  decrypted:  "{decrypted}"')
+
+    if plaintext == decrypted:
+        print("  ✓ Round-trip verified: plaintext matches decrypted")
+    else:
+        raise RuntimeError("Round-trip FAILED: plaintext does not match decrypted")
+
+
+def demo_mine_event(target_qube, nostr_index):
+    print("\n--- Demo 4: mine_event (NIP-13 Proof-of-Work) ---")
+
+    event = {"kind": 1, "content": "Hello Nostr with PoW!", "tags": []}
+
+    print("  Mining with difficulty=4, threads=4, timeout_sec=30...")
+    response = call_nsigner(
+        target_qube,
+        {
+            "id": "5",
+            "method": "mine_event",
+            "params": [json.dumps(event), {
+                "difficulty": 4,
+                "threads": 4,
+                "timeout_sec": 30,
+                "nostr_index": nostr_index,
+            }],
+        },
+    )
+
+    if "error" in response:
+        raise RuntimeError(f"mine_event failed: {json.dumps(response['error'])}")
+
+    result = json.loads(response["result"])
+    print(f"  achieved_difficulty: {result['achieved_difficulty']}")
+    print(f"  target_reached:      {result['target_reached']}")
+    print(f"  elapsed_sec:         {result['elapsed_sec']}")
+    print(f"  attempts:            {result['attempts']}")
+
+    mined_event = json.loads(result["event"])
+    print(f"  event id:            {mined_event['id']}")
+    print(f"  nonce tag:           {mined_event['tags'][0]}")
+
+    if result["target_reached"]:
+        print("  ✓ Target difficulty reached!")
+    else:
+        print(f"  (Target not reached, best effort: {result['achieved_difficulty']} bits)")
+
+
+# --- Main ---
+
+def main():
+    target_qube = sys.argv[1] if len(sys.argv) > 1 else "nostr_signer"
+    nostr_index = int(sys.argv[2]) if len(sys.argv) > 2 else 0
+
+    print("=== n_signer Python Demo ===")
+    print(f"Target qube: {target_qube}")
+    print(f"Service:     qubes.NsignerRpc")
+    print(f"nostr_index: {nostr_index}")
+    print("\nConnecting to n_signer via qrexec...")
+
+    try:
+        pubkey_hex = demo_get_public_key(target_qube, nostr_index)
+        demo_sign_event(target_qube, nostr_index, pubkey_hex)
+        demo_nip44(target_qube, nostr_index, pubkey_hex)
+        demo_mine_event(target_qube, nostr_index)
+
+        print("\n=== Summary ===")
+        print("All demos completed successfully.")
+    except Exception as e:
+        print("\n=== Summary ===")
+        print(f"Demo failed: {e}")
+        sys.exit(1)
+
+
+if __name__ == "__main__":
+    main()

documents/CLIENT_IMPLEMENTATION.md

@@ -127,6 +127,25 @@ Methods are NIP-46 style verbs.
 - `nip44_encrypt`
 - `nip44_decrypt`
 
+### 4.2b Algorithm-based verbs (new)
+
+In addition to the role-based verbs above, the signer supports algorithm-based verbs where the caller specifies `algorithm` and `index` directly:
+
+- `sign` — sign arbitrary bytes (params: `[message_hex, {algorithm, index, scheme?}]`)
+- `verify` — verify a signature (params: `[message_hex, signature_hex, {algorithm, index, scheme?}]`)
+- `encapsulate` — KEM encapsulation (params: `[peer_pubkey_hex, {algorithm}]`)
+- `decapsulate` — KEM decapsulation (params: `[ciphertext_hex, {algorithm, index}]`)
+- `derive_shared_secret` — ECDH key agreement (params: `[peer_pubkey_hex, {algorithm, index}]`)
+- `get_public_key` with `algorithm` parameter — returns structured JSON
+
+Algorithm names: `secp256k1`, `ed25519`, `ml-dsa-65`, `slh-dsa-128s`, `x25519`, `ml-kem-768`
+
+For secp256k1 `sign`/`verify`, the optional `scheme` parameter selects `"schnorr"` (default, BIP-340) or `"ecdsa"`.
+
+Old verb aliases (`sign_data`, `ssh_sign`, `verify_signature`, `kem_encapsulate`, `kem_decapsulate`) map to the new verbs when used with the `algorithm` parameter. Without `algorithm`, they fall through to the role-based path.
+
+See [README.md §4c](../README.md) for full details.
+
 ### 4.3 Selector options
 
 The last param may include selector options:
@@ -484,7 +503,228 @@ Decrypt response:
 
 ---
 
-## 11. Compatibility notes
+## 11. Post-Quantum and Multi-Algorithm Support
+
+n_signer supports six cryptographic algorithms, all derived deterministically
+from the same BIP-39 mnemonic via distinct derivation paths:
+
+| Algorithm | Purpose | Curve string | Purpose string | Derivation path |
+|---|---|---|---|---|
+| `secp256k1` | Nostr (sign_event, NIP-04/44) | `secp256k1` | `nostr` | `m/44'/1237'/<n>'/0/0` (NIP-06) |
+| `ed25519` | SSH signing, general signatures | `ed25519` | `ssh` | `m/44'/102001'/<n>'/0'/0'` (SLIP-0010) |
+| `x25519` | Key agreement (age, ECDH) | `x25519` | `age` | `m/44'/102002'/<n>'/0'/0'` (SLIP-0010) |
+| `ml-dsa-65` | Post-quantum signatures (FIPS 204) | `ml-dsa-65` | `pq-sig` | `m/44'/102003'/<n>'/0'/0'` → seed → PQClean keygen |
+| `slh-dsa-128s` | Post-quantum hash-based signatures (FIPS 205) | `slh-dsa-128s` | `pq-sig` | `m/44'/102004'/<n>'/0'/0'` → seed → PQClean keygen |
+| `ml-kem-768` | Post-quantum key encapsulation (FIPS 203) | `ml-kem-768` | `pq-kem` | `m/44'/102005'/<n>'/0'/0'` → seed → PQClean keygen |
+
+The `102XXX` coin types are unregistered in SLIP-44 and reserved by n_signer
+for PQ/SSH/age algorithm families. All non-secp256k1 paths use SLIP-0010
+all-hardened derivation.
+
+### 11.1 Algorithm key sizes
+
+| Algorithm | Pub key | Priv key | Signature | Ciphertext | Shared secret |
+|---|---|---|---|---|---|
+| secp256k1 | 32 bytes | 32 bytes | 64 bytes | — | — |
+| ed25519 | 32 bytes | 32 bytes | 64 bytes | — | — |
+| x25519 | 32 bytes | 32 bytes | — | — | 32 bytes |
+| ML-DSA-65 | 1952 bytes | 4032 bytes | 3309 bytes | — | — |
+| SLH-DSA-128s | 32 bytes | 64 bytes | 7856 bytes | — | — |
+| ML-KEM-768 | 1184 bytes | 2400 bytes | — | 1088 bytes | 32 bytes |
+
+PQ public keys and signatures are much larger than classical ones. Clients
+must allocate buffers accordingly (ML-DSA-65 pubkey hex = 3904 chars;
+SLH-DSA-128s signature hex = 15712 chars; ML-KEM-768 pubkey hex = 2368 chars).
+
+### 11.2 New verbs
+
+| Verb | Purpose | Allowed (purpose, curve) | Description |
+|---|---|---|---|
+| `sign_data` | pq-sig, ssh | (pq-sig, ml-dsa-65), (pq-sig, slh-dsa-128s), (ssh, ed25519) | Sign arbitrary bytes (not a Nostr event) |
+| `verify_signature` | pq-sig, ssh | same as `sign_data` | Verify a signature against the role's public key |
+| `ssh_sign` | ssh | (ssh, ed25519) | Sign an SSH authentication challenge (ed25519) |
+| `kem_encapsulate` | pq-kem | (pq-kem, ml-kem-768) | Encapsulate: generate ciphertext + shared secret from a peer's ML-KEM public key |
+| `kem_decapsulate` | pq-kem | (pq-kem, ml-kem-768) | Decapsulate: recover shared secret from ciphertext using the role's ML-KEM private key |
+
+The existing Nostr verbs (`sign_event`, `nip44_*`, `nip04_*`, `mine_event`)
+remain restricted to `purpose=nostr + curve=secp256k1`.
+
+### 11.3 Structured `get_public_key` response format
+
+`get_public_key` is a universal verb — it works for all six algorithms.
+
+**For secp256k1 (backward compatibility):** the result is a plain hex string
+(the existing format). Existing Nostr clients are unaffected.
+
+```json
+{ "id": "1", "result": "<64-char hex pubkey>" }
+```
+
+**For secp256k1 with `format: "structured"` option:** new clients can request
+the structured format for consistency:
+
+Request:
+```json
+{
+  "id": "1",
+  "method": "get_public_key",
+  "params": [{ "role": "main", "format": "structured" }]
+}
+```
+
+Response:
+```json
+{
+  "id": "1",
+  "result": "{\"algorithm\":\"secp256k1\",\"public_key\":\"<hex>\",\"key_id\":\"<16 hex>\"}"
+}
+```
+
+**For all other algorithms (ed25519, x25519, ML-DSA-65, SLH-DSA-128s,
+ML-KEM-768):** the result is always a structured JSON object serialized as a
+string:
+
+```json
+{
+  "id": "1",
+  "result": {
+    "algorithm": "ml-dsa-65",
+    "public_key": "<hex-encoded public key>",
+    "key_id": "<first 16 hex chars of public key>"
+  }
+}
+```
+
+The `key_id` is the first 16 hex characters of the public key — a short
+display identifier similar to an SSH key fingerprint. The `result` field is a
+JSON string (the object serialized), so clients must parse it twice: once for
+the JSON-RPC envelope, once for the result object.
+
+### 11.4 Example: `sign_data` (ML-DSA-65)
+
+Request:
+```json
+{
+  "id": "10",
+  "method": "sign_data",
+  "params": ["68656c6c6f", { "role": "pq_sig" }]
+}
+```
+
+Response:
+```json
+{
+  "id": "10",
+  "result": "{\"signature\":\"<hex>\",\"algorithm\":\"ml-dsa-65\"}"
+}
+```
+
+The first param is the message bytes as hex. The signature is hex-encoded
+(3309 bytes = 6618 hex chars for ML-DSA-65).
+
+### 11.5 Example: `verify_signature` (ed25519)
+
+Request:
+```json
+{
+  "id": "11",
+  "method": "verify_signature",
+  "params": ["<msg_hex>", "<sig_hex>", { "role": "ssh_main" }]
+}
+```
+
+Response:
+```json
+{ "id": "11", "result": "{\"valid\":true}" }
+```
+
+The signature is verified against the role's derived public key.
+
+### 11.6 Example: `ssh_sign` (ed25519)
+
+Request:
+```json
+{
+  "id": "12",
+  "method": "ssh_sign",
+  "params": ["<session_id_hex>", { "role": "ssh_main" }]
+}
+```
+
+Response:
+```json
+{
+  "id": "12",
+  "result": "{\"signature\":\"<hex>\",\"algorithm\":\"ed25519\"}"
+}
+```
+
+The first param is the SSH session ID (or challenge) as hex. The signature is
+a raw ed25519 signature (64 bytes = 128 hex chars).
+
+### 11.7 Example: `kem_encapsulate` (ML-KEM-768)
+
+Request:
+```json
+{
+  "id": "13",
+  "method": "kem_encapsulate",
+  "params": ["<peer_pubkey_hex>", { "role": "kem_main" }]
+}
+```
+
+Response:
+```json
+{
+  "id": "13",
+  "result": "{\"ciphertext\":\"<hex>\",\"shared_secret\":\"<hex>\",\"algorithm\":\"ml-kem-768\"}"
+}
+```
+
+The first param is the peer's ML-KEM-768 public key as hex (1184 bytes = 2368
+hex chars). The response contains the ciphertext (1088 bytes = 2176 hex chars)
+and the shared secret (32 bytes = 64 hex chars). The encapsulating party keeps
+the shared secret; the ciphertext is sent to the decapsulating party.
+
+### 11.8 Example: `kem_decapsulate` (ML-KEM-768)
+
+Request:
+```json
+{
+  "id": "14",
+  "method": "kem_decapsulate",
+  "params": ["<ciphertext_hex>", { "role": "kem_main" }]
+}
+```
+
+Response:
+```json
+{
+  "id": "14",
+  "result": "{\"shared_secret\":\"<hex>\",\"algorithm\":\"ml-kem-768\"}"
+}
+```
+
+The first param is the ciphertext from `kem_encapsulate` (1088 bytes = 2176
+hex chars). The decapsulated shared secret will match the encapsulating
+party's shared secret.
+
+### 11.9 Example clients
+
+See the `examples/` directory for working C clients demonstrating the new
+verbs:
+
+- [`examples/pq_sign_example.c`](../examples/pq_sign_example.c) — ML-DSA-65
+  `get_public_key` + `sign_data`
+- [`examples/pq_kem_example.c`](../examples/pq_kem_example.c) — ML-KEM-768
+  `get_public_key` + `kem_encapsulate` + `kem_decapsulate` (verifies shared
+  secrets match)
+- [`examples/ssh_sign_example.c`](../examples/ssh_sign_example.c) — ed25519
+  `get_public_key` + `ssh_sign`
+
+---
+
+## 12. Compatibility notes
 
 - If you are writing an autonomous agent client, pin to explicit socket name and explicit role selector.
 - Keep method support feature-detected (`method_not_found` fallback).

documents/FIPS_DEPLOYMENT.md

@@ -61,13 +61,13 @@ Operational assumptions:
 Run `nsigner` in TCP listen mode:
 
 ```bash
-./build/nsigner --listen tcp:[::]:8080
+./build/nsigner --listen tcp:[::]:11111
 ```
 
 Or bind to a specific FIPS ULA address:
 
 ```bash
-./build/nsigner --listen tcp:[fd00::1234]:8080
+./build/nsigner --listen tcp:[fd00::1234]:11111
 ```
 
 Behavior notes:

documents/SECURITY.md

@@ -215,12 +215,18 @@ The signer enforces a strict `(verb, purpose, curve)` matrix:
 | Verb | Required purpose | Required curve |
 |---|---|---|
 | `sign_event` | `nostr` | `secp256k1` |
-| `get_public_key` | `nostr` | `secp256k1` |
+| `mine_event` | `nostr` | `secp256k1` |
 | `nip04_encrypt` / `nip04_decrypt` | `nostr` | `secp256k1` |
 | `nip44_encrypt` / `nip44_decrypt` | `nostr` | `secp256k1` |
+| `get_public_key` | any | any (must match role's declared curve) |
+| `sign_data` | `ssh` or `pq-sig` | `ed25519`, `ml-dsa-65`, or `slh-dsa-128s` |
+| `verify_signature` | `ssh` or `pq-sig` | `ed25519`, `ml-dsa-65`, or `slh-dsa-128s` |
+| `ssh_sign` | `ssh` | `ed25519` |
+| `kem_encapsulate` | `pq-kem` | `ml-kem-768` |
+| `kem_decapsulate` | `pq-kem` | `ml-kem-768` |
 | Any other verb | rejected | rejected |
 
-A pre-approval to use a Bitcoin-purposed key for `sign_event` does **not** override the enforcement matrix. The approval grants access to the key; enforcement still gates the verb. **Fail-closed**: unknown verbs are rejected, never passed through.
+A pre-approval to use a Bitcoin-purposed key for `sign_event` does **not** override the enforcement matrix. The approval grants access to the key; enforcement still gates the verb. **Fail-closed**: unknown verbs and unlisted `(verb, purpose, curve)` combinations are rejected, never passed through.
 
 This is the layer that prevents (for example) a `bitcoin/secp256k1` key from being used to sign a Nostr event even if some pre-approval entry mistakenly named it. The key's *purpose* is part of its identity; you cannot reuse it across domains.
 
@@ -508,7 +514,86 @@ If any of these statements becomes false in code, that is a security bug worth f
 
 ---
 
-## 16. References
+---
+
+## 16. Post-Quantum Cryptography
+
+`n_signer` supports three post-quantum algorithms alongside the classical secp256k1, ed25519, and x25519:
+
+- **ML-DSA-65** (FIPS 204) — lattice-based post-quantum digital signatures
+- **SLH-DSA-128s** (FIPS 205) — hash-based post-quantum signatures with minimal trust assumptions
+- **ML-KEM-768** (FIPS 203) — lattice-based post-quantum key encapsulation mechanism
+
+These are additional options, not replacements for secp256k1. Nostr continues to use secp256k1 exclusively. PQ algorithms are opt-in per role via `purpose="pq-sig"` or `purpose="pq-kem"`. See [`README.md`](../README.md) §4b for the full crypto palette.
+
+### 16.1 PQ threat model
+
+The primary PQ threat is **harvest-now-decrypt-later**: an adversary records encrypted traffic or key agreement exchanges today, stores them, and decrypts them once a sufficiently large quantum computer becomes available. ML-KEM-768 addresses this for key agreement — a session key encapsulated with ML-KEM-768 cannot be recovered by a future quantum adversary.
+
+For signatures, the future risk is **quantum forgery**: a quantum computer could forge classical signatures (ECDSA, Ed25519) given the public key, undermining authentication retroactively. ML-DSA-65 and SLH-DSA-128s address this by providing signatures that resist quantum forgery. The urgency is lower than for key agreement (signatures are forged when needed, not retroactively decrypted), but forward-looking deployments may want PQ signature keys now.
+
+`n_signer` does not claim to defend against all quantum threats. It provides the PQ primitives; the protocol layer (SSH, TLS, Nostr) must adopt them for the protection to be meaningful.
+
+### 16.2 Deterministic PQ key derivation
+
+PQ private keys are not scalars — they are complex mathematical structures (polynomial matrices for lattice schemes, hypertree seeds for hash-based schemes). You cannot use a 32-byte BIP-32 output directly as a PQ private key.
+
+`n_signer` uses a **non-standard** approach to derive PQ keys deterministically from the mnemonic:
+
+1. Derive a 32-byte seed from the mnemonic using BIP-32/SLIP-0010 HMAC-SHA512 at a PQ-specific derivation path (e.g. `m/44'/102003'/<n>'/0'/0'` for ML-DSA-65).
+2. Feed that seed into a SHAKE-256 DRBG (NIST SP 800-90A style).
+3. Replace PQClean's `randombytes()` callback with this DRBG so keygen is deterministic.
+4. The PQ algorithm expands the DRBG output into the full key pair.
+
+**Security argument:**
+
+- The 32-byte seed from BIP-32 derivation carries full 256 bits of entropy (assuming the mnemonic has full entropy).
+- SHAKE-256 is a NIST-approved XOF; using it as a DRBG seeded with 256 bits of entropy is sufficient for all three PQ algorithms.
+- Each role uses a distinct derivation path (distinct coin types 102003/102004/102005), so compromising one role's PQ key does not compromise others.
+
+**This is non-standard.** There is no NIST or IETF specification for deriving PQ keys from a BIP-39 mnemonic. The approach preserves `n_signer`'s core crash-equals-wipe model: PQ keys are re-derived from the mnemonic on every startup, same as secp256k1. The alternative (random PQ keys with no mnemonic recovery) would break the model.
+
+**Risk:** If a weakness is found in using DRBG output as PQ keygen randomness, all PQ keys derived this way could be affected. Mitigation: per-role distinct derivation paths limit blast radius. The classical algorithms (secp256k1, ed25519, x25519) are unaffected — they do not use the DRBG.
+
+Implementation: [`src/pq_drbg.c`](../src/pq_drbg.c), [`src/pq_crypto.c`](../src/pq_crypto.c).
+
+### 16.3 PQ algorithm maturity
+
+ML-DSA, SLH-DSA, and ML-KEM are FIPS-standardized (FIPS 203, 204, 205) and have undergone extensive NIST scrutiny. However, they are newer than classical algorithms and have less deployment history. They are provided as **additional options**, not replacements. The enforcement matrix (§5.2) ensures PQ keys cannot be used for Nostr operations and vice versa.
+
+### 16.4 SLH-DSA-128s signing latency
+
+SLH-DSA-128s signing on ESP32 can take **5–30 seconds**. This is a UX consideration, not a security issue. The hash-based signature scheme is intentionally compute-bound (that is its security foundation). On the Feather/CYD firmware, the approval prompt should show a "signing..." indicator during the operation.
+
+The user should choose whether to use SLH-DSA-128s per role. For interactive use where latency matters, ML-DSA-65 is faster. SLH-DSA-128s is appropriate for low-frequency, high-assurance signing where minimal trust assumptions (hash-based, no number-theoretic hardness assumption) are desired.
+
+### 16.5 Key sizes and memory
+
+PQ private keys are large compared to classical keys:
+
+| Algorithm | Private key | Public key | Signature / Ciphertext |
+|---|---|---|---|
+| secp256k1 | 32 bytes | 32 bytes | 64 bytes (sig) |
+| ed25519 | 32 bytes | 32 bytes | 64 bytes (sig) |
+| ML-DSA-65 | 4032 bytes | 1952 bytes | 3309 bytes (sig) |
+| SLH-DSA-128s | 64 bytes | 32 bytes | 7856 bytes (sig) |
+| ML-KEM-768 | 2400 bytes | 1184 bytes | 1088 bytes (ciphertext) |
+
+With `ROLE_TABLE_MAX_ENTRIES` at 256, a full table of ML-DSA-65 keys would use ~1 MB of `mlock`'d memory (4032 × 256 ≈ 1.03 MB for private keys alone). This is acceptable on host. On ESP32 with 512 KB SRAM, this would not fit — on-demand derivation (deriving a PQ key only when a request targets that role) is the recommended pattern. The existing [`crypto_derive_one`](../src/key_store.c) path already supports this.
+
+### 16.6 No hybrid signatures yet
+
+Hybrid signatures (e.g., ed25519 + ML-DSA combined into one signature object) are **future work**. No standard exists for hybrid SSH signatures yet. `n_signer` provides the individual primitives (`sign_data` for ed25519, ML-DSA-65, and SLH-DSA-128s); a hybrid format can be assembled by the client once standards solidify.
+
+### 16.7 PQ key persistence
+
+**PQ keys are NOT persisted.** They are re-derived from the mnemonic on every startup, same as secp256k1. There is no PQ key file, no PQ key database, no PQ key cache on disk. Crash-equals-wipe (§10) applies unchanged: if the process dies, all PQ keys are gone and must be re-derived from the mnemonic on next startup.
+
+This is a deliberate design choice. The deterministic derivation approach (§16.2) makes it possible to recover PQ keys from the mnemonic alone, so persistence would add risk (key material on disk) without adding capability.
+
+---
+
+## 17. References
 
 - [`README.md`](../README.md) — authoritative behavior spec.
 - [`plans/nsigner.md`](../plans/nsigner.md) — root design plan and decisions log.
@@ -517,4 +602,5 @@ If any of these statements becomes false in code, that is a security bug worth f
 - [`documents/QUBES_OS.md`](QUBES_OS.md) — Qubes RPC integration.
 - [`documents/FIPS_DEPLOYMENT.md`](FIPS_DEPLOYMENT.md) — FIPS-mode deployment notes.
 - [`plans/seed_phrase_uses.md`](../plans/seed_phrase_uses.md) — what one mnemonic can become.
-- [`src/policy.c`](../src/policy.c), [`src/server.c`](../src/server.c), [`src/dispatcher.c`](../src/dispatcher.c), [`src/role_table.c`](../src/role_table.c), [`src/selector.c`](../src/selector.c), [`src/enforcement.c`](../src/enforcement.c) — the security-related code.
+- [`plans/post_quantum_crypto.md`](../plans/post_quantum_crypto.md) — post-quantum and multi-algorithm crypto expansion plan.
+- [`src/policy.c`](../src/policy.c), [`src/server.c`](../src/server.c), [`src/dispatcher.c`](../src/dispatcher.c), [`src/role_table.c`](../src/role_table.c), [`src/selector.c`](../src/selector.c), [`src/enforcement.c`](../src/enforcement.c), [`src/pq_crypto.c`](../src/pq_crypto.c), [`src/pq_drbg.c`](../src/pq_drbg.c) — the security-related code.

examples/get_pubkey_fips.py

@@ -8,7 +8,7 @@ import time
 from coincurve import PrivateKey
 
 HOST = "npub15uqyclnr3er7r8uhka7f0ae2yt4gkjat8gxdan04q0e6xrnwmtjswcyla3.fips"
-PORT = 8080
+PORT = 11111
 
 # Demo caller key (32 bytes). Replace with your stable caller key in real use.
 PRIVKEY = bytes(range(1, 33))

examples/get_pubkey_qrexec.c

@@ -0,0 +1,110 @@
+/*
+ * get_pubkey_qrexec.c — connect to a running n_signer in another Qubes qube
+ * via qrexec, using the high-level nostr_signer API from nostr_core_lib.
+ *
+ * This demonstrates the new nostr_core_lib client features:
+ *   - nostr_signer_nsigner_qrexec() — qrexec transport
+ *   - nostr_signer_nsigner_set_nostr_index() — index-based key selection
+ *
+ * Usage:
+ *   ./get_pubkey_qrexec <target_qube> [nostr_index]
+ *   ./get_pubkey_qrexec nostr_signer 0
+ *   ./get_pubkey_qrexec nostr_signer 1
+ *
+ * No auth envelope needed — qrexec identity comes from QREXEC_REMOTE_DOMAIN
+ * on the server side.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "nostr_common.h"
+#include "nostr_signer.h"
+#include "nip019.h"
+
+int main(int argc, char **argv) {
+    const char *target_qube;
+    const char *service_name = "qubes.NsignerRpc";
+    int nostr_index = 0;
+    nostr_signer_t *signer = NULL;
+    char pubkey_hex[65];
+    unsigned char pubkey_bytes[32];
+    char npub[128];
+    int rc;
+
+    if (argc < 2) {
+        fprintf(stderr, "Usage: %s <target_qube> [nostr_index]\n", argv[0]);
+        return 1;
+    }
+    target_qube = argv[1];
+    if (argc > 2) {
+        nostr_index = atoi(argv[2]);
+    }
+
+    if (nostr_init() != NOSTR_SUCCESS) {
+        fprintf(stderr, "failed to initialize crypto subsystem\n");
+        return 1;
+    }
+
+    printf("Connecting to n_signer in qube \"%s\" via qrexec (index %d)...\n",
+           target_qube, nostr_index);
+
+    /* Create a high-level signer backed by qrexec transport */
+    signer = nostr_signer_nsigner_qrexec(target_qube, service_name, NULL, 30000);
+    if (signer == NULL) {
+        fprintf(stderr, "failed to create qrexec signer (is qrexec-client-vm available?)\n");
+        nostr_cleanup();
+        return 1;
+    }
+
+    /* Select key by nostr_index (NIP-06 m/44'/1237'/N'/0/0) */
+    if (nostr_signer_nsigner_set_nostr_index(signer, nostr_index) != NOSTR_SUCCESS) {
+        fprintf(stderr, "failed to set nostr_index\n");
+        nostr_signer_free(signer);
+        nostr_cleanup();
+        return 1;
+    }
+
+    /* Request the public key */
+    rc = nostr_signer_get_public_key(signer, pubkey_hex);
+    if (rc != NOSTR_SUCCESS) {
+        if (rc == NOSTR_ERROR_NSIGNER_INDEX_NOT_ALLOWED) {
+            fprintf(stderr, "DENIED: index %d is not in the signer's whitelist\n", nostr_index);
+        } else if (rc == NOSTR_ERROR_NSIGNER_POLICY_DENIED) {
+            fprintf(stderr, "DENIED: policy denied (caller not approved at signer terminal)\n");
+        } else {
+            fprintf(stderr, "get_public_key failed: error code %d\n", rc);
+        }
+        nostr_signer_free(signer);
+        nostr_cleanup();
+        return 1;
+    }
+
+    /* Convert hex pubkey to npub (bech32) */
+    {
+        int i;
+        for (i = 0; i < 32; i++) {
+            unsigned int byte;
+            if (sscanf(pubkey_hex + 2 * i, "%2x", &byte) != 1) {
+                fprintf(stderr, "failed to parse hex pubkey\n");
+                nostr_signer_free(signer);
+                nostr_cleanup();
+                return 1;
+            }
+            pubkey_bytes[i] = (unsigned char)byte;
+        }
+    }
+    if (nostr_key_to_bech32(pubkey_bytes, "npub", npub) != NOSTR_SUCCESS) {
+        fprintf(stderr, "failed to convert to npub\n");
+        nostr_signer_free(signer);
+        nostr_cleanup();
+        return 1;
+    }
+
+    printf("index %d: hex=%s  npub=%s\n", nostr_index, pubkey_hex, npub);
+
+    nostr_signer_free(signer);
+    nostr_cleanup();
+    return 0;
+}

examples/get_pubkey_tcp.c

@@ -4,14 +4,14 @@
  * bech32 npub for each.
  *
  * This is a cross-qube test client for Qubes OS: the signer runs in the
- * nostr_signer qube listening on tcp:[::]:8080, and this client runs in
+ * nostr_signer qube listening on tcp:[::]:11111, and this client runs in
  * a different qube connecting to the signer's FIPS address.
  *
  * Usage:
  *   ./get_pubkey_tcp <host> <port>
- *   ./get_pubkey_tcp npub1xxx...fips 8080
+ *   ./get_pubkey_tcp npub1xxx...fips 11111
  *
- * If no arguments are given, defaults to localhost:8080.
+ * If no arguments are given, defaults to localhost:11111.
  *
  * Output: for each index, prints:
  *   index 0: hex=<64 hex chars>  npub=npub1...
@@ -139,7 +139,7 @@ cleanup:
 
 int main(int argc, char **argv) {
     const char *host = "127.0.0.1";
-    int port = 8080;
+    int port = 11111;
     char hex0[65], npub0[128];
     char hex1[65], npub1[128];
     int failures = 0;

examples/n_signer_qube_example_fips.js

@@ -5,14 +5,14 @@
  * and bech32 npub for each.
  *
  * This is a cross-qube test client for Qubes OS: the signer runs in the
- * nostr_signer qube listening on tcp:[::]:8080, and this client runs in
+ * nostr_signer qube listening on tcp:[::]:11111, and this client runs in
  * a different qube connecting to the signer's FIPS address.
  *
  * Usage:
  *   node n_signer_qube_example.js [host] [port]
- *   node n_signer_qube_example.js fd56:d7c3:f605:719d:15b:18a0:fb06:982f 8080
+ *   node n_signer_qube_example.js fd56:d7c3:f605:719d:15b:18a0:fb06:982f 11111
  *
- * If no arguments are given, defaults to localhost:8080.
+ * If no arguments are given, defaults to localhost:11111.
  *
  * Protocol:
  *   - 4-byte big-endian length prefix + JSON payload (TCP framing)
@@ -214,7 +214,7 @@ function hexToNpub(pubkeyHex) {
 
 async function main() {
   const host = process.argv[2] || "127.0.0.1";
-  const port = parseInt(process.argv[3] || "8080", 10);
+  const port = parseInt(process.argv[3] || "11111", 10);
 
   console.log(`Connecting to n_signer at ${host}:${port}`);
   console.log("Querying get_public_key for nostr_index 0 and 1...\n");

examples/otp_nostr_30078.py

@@ -0,0 +1,219 @@
+#!/usr/bin/env python3
+"""
+otp_nostr_30078.py — example: encrypt data with OTP, wrap in a Nostr kind 30078
+event, sign it with n_signer, and print the signed event for publishing.
+
+Workflow:
+  1. Call n_signer's `otp_encrypt` verb to encrypt plaintext with the bound OTP pad.
+  2. Build a Nostr kind 30078 (replaceable parameterized) event with the ASCII-armored
+     ciphertext as the `content` field.
+  3. Call n_signer's `sign_event` verb to sign the event with the secp256k1 key.
+  4. Print the signed event JSON, ready to publish to Nostr relays.
+
+This is a demo — it does not actually publish to a relay. To publish, send the
+signed event to your preferred Nostr relay using a library like nostr-tools,
+nostril, or nak.
+
+Usage:
+  python3 examples/otp_nostr_30078.py "Your secret message here"
+
+Requirements:
+  - n_signer running with --otp-pad-dir / --otp-pad bound, and a secp256k1
+    role (e.g. "main") available for sign_event.
+  - This script connects to n_signer via stdio (one process per request).
+
+See plans/otp_nostr_integration.md for the full design.
+"""
+import base64
+import hashlib
+import json
+import os
+import struct
+import subprocess
+import sys
+import time
+
+NSIGNER = "./build/nsigner"
+PAD_DIR = "/media/user/Music/pads"
+PAD_SPEC = "333e9902db839d9d"
+MNEMONIC_FILE = ".test_mnemonic"
+MNEMONIC_TMP = ".test_mnemonic_otp_30078.tmp"
+
+
+def send_framed(proc, obj):
+    payload = json.dumps(obj).encode()
+    proc.stdin.write(struct.pack(">I", len(payload)))
+    proc.stdin.write(payload)
+    proc.stdin.flush()
+
+
+def recv_framed(proc):
+    """Read a framed response, skipping any banner text on stdout."""
+    buf = b""
+    while True:
+        b = proc.stdout.read(1)
+        if not b:
+            return None
+        buf = (buf + b)[-4:]
+        if len(buf) < 4:
+            continue
+        (length,) = struct.unpack(">I", buf)
+        if 1 <= length <= 1024 * 1024:
+            peek = proc.stdout.read(1)
+            if peek == b"{":
+                body = peek + proc.stdout.read(length - 1)
+                return json.loads(body.decode())
+            else:
+                buf = (buf + peek)[-4:]
+
+
+def run_one_request(req_obj):
+    """Run nsigner in stdio mode for a single framed request/response."""
+    shell_cmd = (
+        f"exec 3<{MNEMONIC_TMP}; "
+        f"exec {NSIGNER} --listen stdio --mnemonic-fd 3 "
+        f"--otp-pad-dir {PAD_DIR} --otp-pad {PAD_SPEC} "
+        f"--otp-allow-blkback --allow-all"
+    )
+    proc = subprocess.Popen(
+        ["bash", "-c", shell_cmd],
+        stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
+    )
+    import time as _time
+    _time.sleep(1.0)
+    if proc.poll() is not None:
+        err = proc.stderr.read().decode()
+        print(f"ERROR: nsigner exited early (code {proc.returncode})")
+        print(f"stderr: {err}")
+        return None
+    send_framed(proc, req_obj)
+    resp = recv_framed(proc)
+    proc.stdin.close()
+    try:
+        proc.wait(timeout=5)
+    except subprocess.TimeoutExpired:
+        proc.kill()
+    return resp
+
+
+def compute_event_id(event):
+    """Compute the Nostr event ID (SHA-256 of the canonical serialized event)."""
+    # Nostr event serialization: [0, pubkey, created_at, kind, tags, content]
+    serialized = json.dumps([
+        0,
+        event["pubkey"],
+        event["created_at"],
+        event["kind"],
+        event["tags"],
+        event["content"],
+    ], separators=(",", ":"), ensure_ascii=False)
+    return hashlib.sha256(serialized.encode()).hexdigest()
+
+
+def main():
+    plaintext = " ".join(sys.argv[1:]) if len(sys.argv) > 1 else "Secret OTP message"
+    print(f"Plaintext: {plaintext}")
+
+    # Prepare the mnemonic temp file.
+    with open(MNEMONIC_FILE) as f:
+        mnemonic = f.read().strip()
+    with open(MNEMONIC_TMP, "w") as f:
+        f.write(mnemonic + "\n")
+
+    try:
+        # Step 1: Get the public key for the "main" role
+        print("\n=== Step 1: get_public_key ===")
+        resp = run_one_request({
+            "id": "1",
+            "method": "get_public_key",
+            "params": [{"role": "main"}],
+        })
+        if resp is None or "result" not in resp:
+            print("ERROR: get_public_key failed")
+            print(f"Response: {resp}")
+            return 1
+        # The result is a plain hex string for secp256k1 backward compat.
+        pubkey_hex = resp["result"].strip('"')
+        print(f"Public key: {pubkey_hex}")
+
+        # Step 2: Encrypt the plaintext with OTP
+        print("\n=== Step 2: otp_encrypt ===")
+        pt_b64 = base64.b64encode(plaintext.encode()).decode()
+        resp = run_one_request({
+            "id": "2",
+            "method": "otp_encrypt",
+            "params": [pt_b64, {"encoding": "ascii"}],
+        })
+        if resp is None or "result" not in resp:
+            print("ERROR: otp_encrypt failed")
+            print(f"Response: {resp}")
+            return 1
+        enc_result = json.loads(resp["result"])
+        ciphertext = enc_result["ciphertext"]
+        pad_chksum = enc_result["pad_chksum"]
+        pad_offset = enc_result["pad_offset_after"]
+        print(f"Pad checksum: {pad_chksum}")
+        print(f"Pad offset after encrypt: {pad_offset}")
+        print(f"Ciphertext (first 60 chars): {ciphertext[:60]}...")
+
+        # Step 3: Build the Nostr kind 30078 event
+        print("\n=== Step 3: Build kind 30078 event ===")
+        # Use a unique d-tag based on the pad checksum and offset.
+        d_tag = f"otp-{pad_chksum[:16]}-{pad_offset}"
+        event = {
+            "pubkey": pubkey_hex,
+            "created_at": int(time.time()),
+            "kind": 30078,
+            "tags": [
+                ["d", d_tag],
+                ["otp-pad", pad_chksum[:16]],
+                ["otp-version", "v0.0.2-otp"],
+                ["otp-encoding", "ascii"],
+            ],
+            "content": ciphertext,
+        }
+        # Compute the event ID.
+        event_id = compute_event_id(event)
+        event["id"] = event_id
+        print(f"Event ID: {event_id}")
+        print(f"d-tag: {d_tag}")
+
+        # Step 4: Sign the event with n_signer
+        print("\n=== Step 4: sign_event ===")
+        # sign_event expects the event JSON as the first param (without id/sig).
+        # The signer computes the id and signature internally.
+        event_for_signing = {
+            "pubkey": event["pubkey"],
+            "created_at": event["created_at"],
+            "kind": event["kind"],
+            "tags": event["tags"],
+            "content": event["content"],
+        }
+        resp = run_one_request({
+            "id": "3",
+            "method": "sign_event",
+            "params": [json.dumps(event_for_signing), {"role": "main"}],
+        })
+        if resp is None or "result" not in resp:
+            print("ERROR: sign_event failed")
+            print(f"Response: {resp}")
+            return 1
+        sig = resp["result"].strip('"')
+        event["sig"] = sig
+        print(f"Signature: {sig[:60]}...")
+
+        # Step 5: Print the signed event
+        print("\n=== Signed Nostr event (ready to publish) ===")
+        print(json.dumps(event, indent=2))
+        print(f"\nTo publish: send this event to a Nostr relay.")
+        print(f"To decrypt: call otp_decrypt with the content field.")
+        return 0
+    finally:
+        try:
+            os.unlink(MNEMONIC_TMP)
+        except OSError:
+            pass
+
+
+if __name__ == "__main__":
+    sys.exit(main())

examples/pq_kem_example.c

@@ -0,0 +1,273 @@
+/*
+ * pq_kem_example.c — connect to a running n_signer over its abstract UNIX
+ * socket and demonstrate post-quantum key encapsulation with ML-KEM-768.
+ *
+ * The example:
+ *   1. Sends a get_public_key request for an ML-KEM-768 role ("kem_main").
+ *   2. Prints the structured public key (algorithm, public_key, key_id).
+ *   3. Sends a kem_encapsulate request with the public key, obtaining a
+ *      ciphertext + shared secret.
+ *   4. Sends a kem_decapsulate request with the ciphertext, recovering the
+ *      shared secret on the signer side.
+ *   5. Prints both shared secrets — they should match.
+ *
+ * Prerequisites:
+ *   - n_signer must be running with a role configured for purpose=pq-kem,
+ *     curve=ml-kem-768, named "kem_main" (or pass the role name as the 2nd arg).
+ *   - A mnemonic must be loaded in the signer.
+ *
+ * Usage: ./pq_kem_example [socket_name] [role_name]
+ *
+ * Default socket_name: nsigner
+ * Default role_name:   kem_main
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "nostr_common.h"
+#include "nsigner_transport.h"
+#include "nsigner_client.h"
+#include "../cjson/cJSON.h"
+
+static int get_structured_pubkey(nsigner_client_t *client, const char *role,
+                                  char **out_pub_hex) {
+    cJSON *params = NULL;
+    cJSON *opts = NULL;
+    cJSON *result = NULL;
+    cJSON *parsed = NULL;
+    int rc = -1;
+
+    *out_pub_hex = NULL;
+
+    params = cJSON_CreateArray();
+    if (params == NULL) return -1;
+
+    opts = cJSON_CreateObject();
+    if (opts == NULL) {
+        cJSON_Delete(params);
+        return -1;
+    }
+    cJSON_AddStringToObject(opts, "role", role);
+    cJSON_AddItemToArray(params, opts);
+    opts = NULL;
+
+    if (nsigner_client_call(client, "get_public_key", params, &result) != NOSTR_SUCCESS) {
+        cJSON_Delete(params);
+        return -1;
+    }
+    params = NULL;
+
+    if (cJSON_IsString(result)) {
+        parsed = cJSON_Parse(result->valuestring);
+        if (parsed != NULL) {
+            cJSON *pk_item = cJSON_GetObjectItemCaseSensitive(parsed, "public_key");
+            if (cJSON_IsString(pk_item)) {
+                *out_pub_hex = strdup(pk_item->valuestring);
+                rc = 0;
+            }
+        }
+    }
+
+    cJSON_Delete(parsed);
+    cJSON_Delete(result);
+    cJSON_Delete(params);
+    return rc;
+}
+
+/* kem_encapsulate: returns ciphertext_hex and shared_secret_hex (newly
+ * allocated, caller frees). */
+static int kem_encapsulate(nsigner_client_t *client, const char *role,
+                            const char *pub_hex,
+                            char **out_ct_hex, char **out_ss_hex) {
+    cJSON *params = NULL;
+    cJSON *opts = NULL;
+    cJSON *result = NULL;
+    int rc = -1;
+
+    *out_ct_hex = NULL;
+    *out_ss_hex = NULL;
+
+    params = cJSON_CreateArray();
+    if (params == NULL) return -1;
+
+    cJSON_AddItemToArray(params, cJSON_CreateString(pub_hex));
+
+    opts = cJSON_CreateObject();
+    if (opts == NULL) {
+        cJSON_Delete(params);
+        return -1;
+    }
+    cJSON_AddStringToObject(opts, "role", role);
+    cJSON_AddItemToArray(params, opts);
+    opts = NULL;
+
+    if (nsigner_client_call(client, "kem_encapsulate", params, &result) != NOSTR_SUCCESS) {
+        cJSON_Delete(params);
+        return -1;
+    }
+    params = NULL;
+
+    if (cJSON_IsString(result)) {
+        cJSON *parsed = cJSON_Parse(result->valuestring);
+        if (parsed != NULL) {
+            cJSON *ct_item = cJSON_GetObjectItemCaseSensitive(parsed, "ciphertext");
+            cJSON *ss_item = cJSON_GetObjectItemCaseSensitive(parsed, "shared_secret");
+            if (cJSON_IsString(ct_item) && cJSON_IsString(ss_item)) {
+                *out_ct_hex = strdup(ct_item->valuestring);
+                *out_ss_hex = strdup(ss_item->valuestring);
+                if (*out_ct_hex != NULL && *out_ss_hex != NULL) {
+                    rc = 0;
+                }
+            }
+            cJSON_Delete(parsed);
+        }
+    }
+
+    cJSON_Delete(result);
+    cJSON_Delete(params);
+    return rc;
+}
+
+static char *kem_decapsulate(nsigner_client_t *client, const char *role,
+                              const char *ct_hex) {
+    cJSON *params = NULL;
+    cJSON *opts = NULL;
+    cJSON *result = NULL;
+    char *ss_hex = NULL;
+
+    params = cJSON_CreateArray();
+    if (params == NULL) return NULL;
+
+    cJSON_AddItemToArray(params, cJSON_CreateString(ct_hex));
+
+    opts = cJSON_CreateObject();
+    if (opts == NULL) {
+        cJSON_Delete(params);
+        return NULL;
+    }
+    cJSON_AddStringToObject(opts, "role", role);
+    cJSON_AddItemToArray(params, opts);
+    opts = NULL;
+
+    if (nsigner_client_call(client, "kem_decapsulate", params, &result) != NOSTR_SUCCESS) {
+        cJSON_Delete(params);
+        return NULL;
+    }
+    params = NULL;
+
+    if (cJSON_IsString(result)) {
+        cJSON *parsed = cJSON_Parse(result->valuestring);
+        if (parsed != NULL) {
+            cJSON *ss_item = cJSON_GetObjectItemCaseSensitive(parsed, "shared_secret");
+            if (cJSON_IsString(ss_item)) {
+                ss_hex = strdup(ss_item->valuestring);
+            }
+            cJSON_Delete(parsed);
+        }
+    }
+
+    cJSON_Delete(result);
+    cJSON_Delete(params);
+    return ss_hex;
+}
+
+int main(int argc, char **argv) {
+    const char *socket_name = "nsigner";
+    const char *role = "kem_main";
+    nsigner_transport_t *transport = NULL;
+    nsigner_client_t *client = NULL;
+    char *pub_hex = NULL;
+    char *ct_hex = NULL;
+    char *encap_ss_hex = NULL;
+    char *decap_ss_hex = NULL;
+    int rc = 1;
+
+    if (argc > 1 && argv[1] != NULL && argv[1][0] != '\0') {
+        socket_name = argv[1];
+    }
+    if (argc > 2 && argv[2] != NULL && argv[2][0] != '\0') {
+        role = argv[2];
+    }
+
+    if (nostr_init() != NOSTR_SUCCESS) {
+        fprintf(stderr, "failed to initialize crypto subsystem\n");
+        return 1;
+    }
+
+    transport = nsigner_transport_open_unix(socket_name, 10000);
+    if (transport == NULL) {
+        fprintf(stderr, "connect failed: cannot open unix transport @%s\n", socket_name);
+        goto cleanup;
+    }
+
+    client = nsigner_client_new(transport);
+    if (client == NULL) {
+        fprintf(stderr, "connect failed: cannot create nsigner client\n");
+        transport->close(transport);
+        goto cleanup;
+    }
+    transport = NULL;
+
+    printf("=== PQ KEM Example (ML-KEM-768) ===\n");
+    printf("socket: %s\n", socket_name);
+    printf("role:   %s\n", role);
+    printf("\n");
+
+    /* 1. Get the ML-KEM-768 public key. */
+    if (get_structured_pubkey(client, role, &pub_hex) != 0 || pub_hex == NULL) {
+        fprintf(stderr, "get_public_key failed: %s\n",
+                nsigner_client_last_error(client));
+        goto cleanup;
+    }
+    printf("Public Key:\n");
+    printf("  pub_len: %zu hex chars (%zu bytes)\n",
+           strlen(pub_hex), strlen(pub_hex) / 2);
+    printf("  pub_head: %.64s...\n", pub_hex);
+    printf("\n");
+
+    /* 2. Encapsulate with the public key. */
+    printf("Encapsulating with public key...\n");
+    if (kem_encapsulate(client, role, pub_hex, &ct_hex, &encap_ss_hex) != 0) {
+        fprintf(stderr, "kem_encapsulate failed: %s\n",
+                nsigner_client_last_error(client));
+        goto cleanup;
+    }
+    printf("Ciphertext:\n");
+    printf("  ct_len: %zu hex chars (%zu bytes)\n",
+           strlen(ct_hex), strlen(ct_hex) / 2);
+    printf("  ct_head: %.64s...\n", ct_hex);
+    printf("Encapsulated shared secret:\n");
+    printf("  ss: %s\n", encap_ss_hex);
+    printf("\n");
+
+    /* 3. Decapsulate with the ciphertext (uses the role's private key). */
+    printf("Decapsulating ciphertext on signer side...\n");
+    decap_ss_hex = kem_decapsulate(client, role, ct_hex);
+    if (decap_ss_hex == NULL) {
+        fprintf(stderr, "kem_decapsulate failed: %s\n",
+                nsigner_client_last_error(client));
+        goto cleanup;
+    }
+    printf("Decapsulated shared secret:\n");
+    printf("  ss: %s\n", decap_ss_hex);
+    printf("\n");
+
+    /* 4. Verify the shared secrets match. */
+    if (strcmp(encap_ss_hex, decap_ss_hex) == 0) {
+        printf("SUCCESS: shared secrets match!\n");
+        rc = 0;
+    } else {
+        printf("FAILURE: shared secrets do NOT match!\n");
+    }
+
+cleanup:
+    free(pub_hex);
+    free(ct_hex);
+    free(encap_ss_hex);
+    free(decap_ss_hex);
+    nsigner_client_free(client);
+    nostr_cleanup();
+    return rc;
+}

examples/pq_sign_example.c

@@ -0,0 +1,215 @@
+/*
+ * pq_sign_example.c — connect to a running n_signer over its abstract UNIX
+ * socket and demonstrate post-quantum signing with ML-DSA-65.
+ *
+ * The example:
+ *   1. Sends a get_public_key request for an ML-DSA-65 role ("pq_sig").
+ *   2. Prints the structured public key (algorithm, public_key, key_id).
+ *   3. Sends a sign_data request with a test message.
+ *   4. Prints the signature (hex) and algorithm.
+ *
+ * Prerequisites:
+ *   - n_signer must be running with a role configured for purpose=pq-sig,
+ *     curve=ml-dsa-65, named "pq_sig" (or pass the role name as the 2nd arg).
+ *   - A mnemonic must be loaded in the signer.
+ *
+ * Usage: ./pq_sign_example [socket_name] [role_name]
+ *
+ * Default socket_name: nsigner
+ * Default role_name:   pq_sig
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "nostr_common.h"
+#include "nsigner_transport.h"
+#include "nsigner_client.h"
+#include "../cjson/cJSON.h"
+
+static int get_structured_pubkey(nsigner_client_t *client, const char *role,
+                                  cJSON **out_obj) {
+    cJSON *params = NULL;
+    cJSON *opts = NULL;
+    cJSON *result = NULL;
+    cJSON *parsed = NULL;
+    int rc = -1;
+
+    *out_obj = NULL;
+
+    params = cJSON_CreateArray();
+    if (params == NULL) return -1;
+
+    opts = cJSON_CreateObject();
+    if (opts == NULL) {
+        cJSON_Delete(params);
+        return -1;
+    }
+    cJSON_AddStringToObject(opts, "role", role);
+    cJSON_AddItemToArray(params, opts);
+    opts = NULL;
+
+    if (nsigner_client_call(client, "get_public_key", params, &result) != NOSTR_SUCCESS) {
+        cJSON_Delete(params);
+        return -1;
+    }
+    params = NULL;
+
+    /* result is a cJSON string containing the serialized structured object. */
+    if (cJSON_IsString(result)) {
+        parsed = cJSON_Parse(result->valuestring);
+        if (parsed != NULL && cJSON_IsObject(parsed)) {
+            *out_obj = parsed;
+            parsed = NULL;
+            rc = 0;
+        }
+    }
+
+    cJSON_Delete(parsed);
+    cJSON_Delete(result);
+    cJSON_Delete(params);
+    return rc;
+}
+
+static char *sign_data(nsigner_client_t *client, const char *role,
+                        const char *msg_hex) {
+    cJSON *params = NULL;
+    cJSON *opts = NULL;
+    cJSON *result = NULL;
+    char *sig_hex = NULL;
+
+    params = cJSON_CreateArray();
+    if (params == NULL) return NULL;
+
+    cJSON_AddItemToArray(params, cJSON_CreateString(msg_hex));
+
+    opts = cJSON_CreateObject();
+    if (opts == NULL) {
+        cJSON_Delete(params);
+        return NULL;
+    }
+    cJSON_AddStringToObject(opts, "role", role);
+    cJSON_AddItemToArray(params, opts);
+    opts = NULL;
+
+    if (nsigner_client_call(client, "sign_data", params, &result) != NOSTR_SUCCESS) {
+        cJSON_Delete(params);
+        return NULL;
+    }
+    params = NULL;
+
+    /* result is a string containing {"signature":"<hex>","algorithm":"<alg>"} */
+    if (cJSON_IsString(result)) {
+        cJSON *parsed = cJSON_Parse(result->valuestring);
+        if (parsed != NULL) {
+            cJSON *sig_item = cJSON_GetObjectItemCaseSensitive(parsed, "signature");
+            if (cJSON_IsString(sig_item)) {
+                sig_hex = strdup(sig_item->valuestring);
+            }
+            cJSON_Delete(parsed);
+        }
+    }
+
+    cJSON_Delete(result);
+    cJSON_Delete(params);
+    return sig_hex;
+}
+
+int main(int argc, char **argv) {
+    const char *socket_name = "nsigner";
+    const char *role = "pq_sig";
+    /* "hello post-quantum world" in hex */
+    const char *msg_hex = "68656c6c6f20706f73742d7175616e74756d20776f726c64";
+    nsigner_transport_t *transport = NULL;
+    nsigner_client_t *client = NULL;
+    cJSON *pubkey_obj = NULL;
+    char *sig_hex = NULL;
+    int rc = 1;
+
+    if (argc > 1 && argv[1] != NULL && argv[1][0] != '\0') {
+        socket_name = argv[1];
+    }
+    if (argc > 2 && argv[2] != NULL && argv[2][0] != '\0') {
+        role = argv[2];
+    }
+
+    if (nostr_init() != NOSTR_SUCCESS) {
+        fprintf(stderr, "failed to initialize crypto subsystem\n");
+        return 1;
+    }
+
+    transport = nsigner_transport_open_unix(socket_name, 10000);
+    if (transport == NULL) {
+        fprintf(stderr, "connect failed: cannot open unix transport @%s\n", socket_name);
+        goto cleanup;
+    }
+
+    client = nsigner_client_new(transport);
+    if (client == NULL) {
+        fprintf(stderr, "connect failed: cannot create nsigner client\n");
+        transport->close(transport);
+        goto cleanup;
+    }
+    transport = NULL;
+
+    printf("=== PQ Sign Example (ML-DSA-65) ===\n");
+    printf("socket: %s\n", socket_name);
+    printf("role:   %s\n", role);
+    printf("\n");
+
+    /* 1. Get the structured public key. */
+    if (get_structured_pubkey(client, role, &pubkey_obj) != 0 || pubkey_obj == NULL) {
+        fprintf(stderr, "get_public_key failed: %s\n",
+                nsigner_client_last_error(client));
+        goto cleanup;
+    }
+
+    {
+        cJSON *alg_item = cJSON_GetObjectItemCaseSensitive(pubkey_obj, "algorithm");
+        cJSON *pk_item = cJSON_GetObjectItemCaseSensitive(pubkey_obj, "public_key");
+        cJSON *kid_item = cJSON_GetObjectItemCaseSensitive(pubkey_obj, "key_id");
+
+        printf("Public Key:\n");
+        printf("  algorithm: %s\n",
+               (cJSON_IsString(alg_item)) ? alg_item->valuestring : "?");
+        printf("  key_id:    %s\n",
+               (cJSON_IsString(kid_item)) ? kid_item->valuestring : "?");
+        if (cJSON_IsString(pk_item)) {
+            /* ML-DSA-65 public key is 3904 hex chars — print length + prefix. */
+            printf("  pub_len:   %zu hex chars (%zu bytes)\n",
+                   strlen(pk_item->valuestring), strlen(pk_item->valuestring) / 2);
+            printf("  pub_head:  %.64s...\n", pk_item->valuestring);
+        } else {
+            printf("  public_key: (missing)\n");
+        }
+    }
+    printf("\n");
+
+    /* 2. Sign a test message. */
+    printf("Signing message (hex): %s\n", msg_hex);
+    sig_hex = sign_data(client, role, msg_hex);
+    if (sig_hex == NULL) {
+        fprintf(stderr, "sign_data failed: %s\n",
+                nsigner_client_last_error(client));
+        goto cleanup;
+    }
+
+    printf("Signature:\n");
+    printf("  sig_len: %zu hex chars (%zu bytes)\n",
+           strlen(sig_hex), strlen(sig_hex) / 2);
+    printf("  sig_head: %.64s...\n", sig_hex);
+    printf("\n");
+
+    printf("To verify externally, use ML-DSA-65 (FIPS 204) verify with the\n");
+    printf("public key above, the message, and this signature.\n");
+
+    rc = 0;
+
+cleanup:
+    free(sig_hex);
+    cJSON_Delete(pubkey_obj);
+    nsigner_client_free(client);
+    nostr_cleanup();
+    return rc;
+}

examples/ssh_sign_example.c

@@ -0,0 +1,212 @@
+/*
+ * ssh_sign_example.c — connect to a running n_signer over its abstract UNIX
+ * socket and demonstrate SSH signing with ed25519.
+ *
+ * The example:
+ *   1. Sends a get_public_key request for an SSH/ed25519 role ("ssh_main").
+ *   2. Prints the structured public key (algorithm, public_key, key_id).
+ *   3. Sends an ssh_sign request with a test session ID.
+ *   4. Prints the signature (hex) and algorithm.
+ *
+ * Prerequisites:
+ *   - n_signer must be running with a role configured for purpose=ssh,
+ *     curve=ed25519, named "ssh_main" (or pass the role name as the 2nd arg).
+ *   - A mnemonic must be loaded in the signer.
+ *
+ * Usage: ./ssh_sign_example [socket_name] [role_name]
+ *
+ * Default socket_name: nsigner
+ * Default role_name:   ssh_main
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "nostr_common.h"
+#include "nsigner_transport.h"
+#include "nsigner_client.h"
+#include "../cjson/cJSON.h"
+
+static int get_structured_pubkey(nsigner_client_t *client, const char *role,
+                                  char **out_pub_hex, char **out_key_id) {
+    cJSON *params = NULL;
+    cJSON *opts = NULL;
+    cJSON *result = NULL;
+    cJSON *parsed = NULL;
+    int rc = -1;
+
+    *out_pub_hex = NULL;
+    *out_key_id = NULL;
+
+    params = cJSON_CreateArray();
+    if (params == NULL) return -1;
+
+    opts = cJSON_CreateObject();
+    if (opts == NULL) {
+        cJSON_Delete(params);
+        return -1;
+    }
+    cJSON_AddStringToObject(opts, "role", role);
+    cJSON_AddItemToArray(params, opts);
+    opts = NULL;
+
+    if (nsigner_client_call(client, "get_public_key", params, &result) != NOSTR_SUCCESS) {
+        cJSON_Delete(params);
+        return -1;
+    }
+    params = NULL;
+
+    if (cJSON_IsString(result)) {
+        parsed = cJSON_Parse(result->valuestring);
+        if (parsed != NULL) {
+            cJSON *pk_item = cJSON_GetObjectItemCaseSensitive(parsed, "public_key");
+            cJSON *kid_item = cJSON_GetObjectItemCaseSensitive(parsed, "key_id");
+            if (cJSON_IsString(pk_item)) {
+                *out_pub_hex = strdup(pk_item->valuestring);
+            }
+            if (cJSON_IsString(kid_item)) {
+                *out_key_id = strdup(kid_item->valuestring);
+            }
+            if (*out_pub_hex != NULL) {
+                rc = 0;
+            }
+        }
+    }
+
+    cJSON_Delete(parsed);
+    cJSON_Delete(result);
+    cJSON_Delete(params);
+    return rc;
+}
+
+static char *ssh_sign(nsigner_client_t *client, const char *role,
+                       const char *msg_hex) {
+    cJSON *params = NULL;
+    cJSON *opts = NULL;
+    cJSON *result = NULL;
+    char *sig_hex = NULL;
+
+    params = cJSON_CreateArray();
+    if (params == NULL) return NULL;
+
+    cJSON_AddItemToArray(params, cJSON_CreateString(msg_hex));
+
+    opts = cJSON_CreateObject();
+    if (opts == NULL) {
+        cJSON_Delete(params);
+        return NULL;
+    }
+    cJSON_AddStringToObject(opts, "role", role);
+    cJSON_AddItemToArray(params, opts);
+    opts = NULL;
+
+    if (nsigner_client_call(client, "ssh_sign", params, &result) != NOSTR_SUCCESS) {
+        cJSON_Delete(params);
+        return NULL;
+    }
+    params = NULL;
+
+    if (cJSON_IsString(result)) {
+        cJSON *parsed = cJSON_Parse(result->valuestring);
+        if (parsed != NULL) {
+            cJSON *sig_item = cJSON_GetObjectItemCaseSensitive(parsed, "signature");
+            if (cJSON_IsString(sig_item)) {
+                sig_hex = strdup(sig_item->valuestring);
+            }
+            cJSON_Delete(parsed);
+        }
+    }
+
+    cJSON_Delete(result);
+    cJSON_Delete(params);
+    return sig_hex;
+}
+
+int main(int argc, char **argv) {
+    const char *socket_name = "nsigner";
+    const char *role = "ssh_main";
+    /* A fake SSH session ID (32 bytes = 64 hex chars) for demonstration. */
+    const char *session_id_hex =
+        "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef";
+    nsigner_transport_t *transport = NULL;
+    nsigner_client_t *client = NULL;
+    char *pub_hex = NULL;
+    char *key_id = NULL;
+    char *sig_hex = NULL;
+    int rc = 1;
+
+    if (argc > 1 && argv[1] != NULL && argv[1][0] != '\0') {
+        socket_name = argv[1];
+    }
+    if (argc > 2 && argv[2] != NULL && argv[2][0] != '\0') {
+        role = argv[2];
+    }
+
+    if (nostr_init() != NOSTR_SUCCESS) {
+        fprintf(stderr, "failed to initialize crypto subsystem\n");
+        return 1;
+    }
+
+    transport = nsigner_transport_open_unix(socket_name, 10000);
+    if (transport == NULL) {
+        fprintf(stderr, "connect failed: cannot open unix transport @%s\n", socket_name);
+        goto cleanup;
+    }
+
+    client = nsigner_client_new(transport);
+    if (client == NULL) {
+        fprintf(stderr, "connect failed: cannot create nsigner client\n");
+        transport->close(transport);
+        goto cleanup;
+    }
+    transport = NULL;
+
+    printf("=== SSH Sign Example (ed25519) ===\n");
+    printf("socket: %s\n", socket_name);
+    printf("role:   %s\n", role);
+    printf("\n");
+
+    /* 1. Get the ed25519 public key. */
+    if (get_structured_pubkey(client, role, &pub_hex, &key_id) != 0 ||
+        pub_hex == NULL) {
+        fprintf(stderr, "get_public_key failed: %s\n",
+                nsigner_client_last_error(client));
+        goto cleanup;
+    }
+    printf("Public Key:\n");
+    printf("  algorithm: ed25519\n");
+    printf("  key_id:    %s\n", (key_id != NULL) ? key_id : "?");
+    printf("  pub_len:   %zu hex chars (%zu bytes)\n",
+           strlen(pub_hex), strlen(pub_hex) / 2);
+    printf("  pubkey:    %s\n", pub_hex);
+    printf("\n");
+
+    /* 2. Sign a test SSH session ID. */
+    printf("Signing SSH session ID (hex): %s\n", session_id_hex);
+    sig_hex = ssh_sign(client, role, session_id_hex);
+    if (sig_hex == NULL) {
+        fprintf(stderr, "ssh_sign failed: %s\n",
+                nsigner_client_last_error(client));
+        goto cleanup;
+    }
+
+    printf("Signature:\n");
+    printf("  sig_len: %zu hex chars (%zu bytes)\n",
+           strlen(sig_hex), strlen(sig_hex) / 2);
+    printf("  sig:     %s\n", sig_hex);
+    printf("\n");
+
+    printf("This ed25519 signature can be verified with the public key above\n");
+    printf("using standard ed25519 verify (e.g. libsodium, OpenSSL EVP_DigestVerify).\n");
+
+    rc = 0;
+
+cleanup:
+    free(pub_hex);
+    free(key_id);
+    free(sig_hex);
+    nsigner_client_free(client);
+    nostr_cleanup();
+    return rc;
+}

firmware/README.md

@@ -99,3 +99,165 @@ Notes:
 - Typical working range is ~4.7uF to 22uF; 10uF is recommended
 - Keep leads short for best stability
 - Auto-reset behavior for flashing may still work, but if flashing ever becomes unreliable, enter bootloader manually
+
+## Post-quantum crypto support (Phase 7)
+
+Both firmware targets (`feather_s3_tft` and `cyd_esp32_2432s028`) now include
+the three NIST-standardized post-quantum algorithms alongside the existing
+secp256k1 (Nostr) and new ed25519/x25519 classical algorithms:
+
+| Algorithm | Standard | Purpose | Pub key | Priv key | Sig/Ct |
+|---|---|---|---|---|---|
+| secp256k1 | — | Nostr (existing) | 32 B | 32 B | 64 B |
+| ed25519 | RFC 8032 | SSH signatures | 32 B | 32 B | 64 B |
+| x25519 | RFC 7748 | Key agreement (age) | 32 B | 32 B | — |
+| ML-DSA-65 | FIPS 204 | PQ signatures | 1952 B | 4032 B | 3309 B |
+| SLH-DSA-128s | FIPS 205 | PQ hash-based sigs | 32 B | 64 B | 7856 B |
+| ML-KEM-768 | FIPS 203 | PQ key encapsulation | 1184 B | 2400 B | 1088 B |
+
+### mbedtls backend (vs OpenSSL on host)
+
+The host build uses OpenSSL EVP for SHA-256, SHA-512, SHA3-256, SHA3-512,
+SHAKE-128, and SHAKE-256. On ESP32, OpenSSL is not available. Instead, the
+firmware uses a **crypto backend abstraction** ([`resources/pqclean/common/crypto_backend.h`](../resources/pqclean/common/crypto_backend.h))
+with two implementations:
+
+- [`resources/pqclean/common/crypto_backend_openssl.c`](../resources/pqclean/common/crypto_backend_openssl.c) — host build (OpenSSL EVP)
+- [`resources/pqclean/common/crypto_backend_mbedtls.c`](../resources/pqclean/common/crypto_backend_mbedtls.c) — ESP32 firmware (mbedtls)
+
+The mbedtls backend uses:
+- `mbedtls_sha256_ret()` for SHA-256 (ESP32-S3 hardware accelerated)
+- `mbedtls_sha512_ret()` for SHA-512 (ESP32-S3 hardware accelerated)
+- `mbedtls_md` API for SHA3-256, SHA3-512, SHAKE-128, SHAKE-256
+
+### Enabling SHA3/SHAKE in menuconfig
+
+mbedtls does not enable SHA3/SHAKE by default. You must enable them in
+menuconfig before building:
+
+```
+Component config → mbedTLS → Hash functions → SHA-3
+Component config → mbedTLS → Hash functions → SHAKE
+```
+
+Or add to `sdkconfig.defaults`:
+```
+CONFIG_MBEDTLS_SHA3_C=y
+CONFIG_MBEDTLS_SHAKE_C=y
+```
+
+If mbedtls does not have SHAKE support, the firmware build will fail at link
+time with unresolved `mbedtls_md_info_from_type(MBEDTLS_MD_SHAKE128)`. In that
+case, either enable the config options above or patch mbedtls with a
+Keccak/SHAKE contribution.
+
+### PQClean component
+
+The PQClean algorithm code is compiled as an ESP-IDF component at
+`components/pqclean/`. The component's `CMakeLists.txt` references the shared
+source files in [`resources/pqclean/`](../resources/pqclean/) via relative
+paths, so there is a single source of truth for both host and firmware builds.
+
+The component includes:
+- ML-DSA-65: `sign.c`, `poly.c`, `ntt.c`
+- SLH-DSA-128s: `sign.c`, `fors.c`, `wots.c`, `hash.c`, `thash.c`, `address.c`, `utils.c`
+- ML-KEM-768: `kem.c`, `indcpa.c`, `poly.c`, `ntt.c`, `cbd.c`, `reduce.c`, `symmetric.c`, `verify.c`
+- Common: `fips202.c`, `sha2.c`, `crypto_backend_mbedtls.c`
+- Firmware DRBG: `pq_drbg_firmware.c`, `randombytes_mbedtls.c`
+
+### Flash usage estimates
+
+| Algorithm | Code size (approx) |
+|---|---|
+| ML-DSA-65 | ~150 KB |
+| SLH-DSA-128s | ~80 KB |
+| ML-KEM-768 | ~120 KB |
+| Total PQ code | ~350 KB |
+
+The ESP32-S3 (Feather S3 TFT) has 8 MB flash and the ESP32 (CYD) has 4 MB
+flash. The PQ code fits comfortably in both, but partition sizes may need
+adjustment if the total app image exceeds the default partition.
+
+### RAM usage notes
+
+PQ key buffers are large compared to classical ECC keys:
+
+| Buffer | Size |
+|---|---|
+| ML-DSA-65 private key | 4032 bytes |
+| ML-DSA-65 public key | 1952 bytes |
+| ML-DSA-65 signature | 3309 bytes |
+| SLH-DSA-128s signature | 7856 bytes |
+| ML-KEM-768 private key | 2400 bytes |
+| ML-KEM-768 public key | 1184 bytes |
+| ML-KEM-768 ciphertext | 1088 bytes |
+
+The ESP32 has ~320 KB available heap (after WiFi/BT are disabled). These
+buffers **must not be stack-allocated** — the default task stack is 8 KB.
+Use `malloc()` or static buffers. The firmware derives PQ keys **on demand**
+(not all at startup) to keep peak RAM usage low.
+
+### SLH-DSA-128s signing latency warning
+
+SLH-DSA-128s (SPHINCS+-128s) is a hash-based signature scheme with a deep
+hypertree structure (7 layers of WOTS+ + Merkle trees). On the ESP32-S3
+(240 MHz dual-core), expect:
+
+- **Key generation**: 5–30 seconds
+- **Signing**: 5–30 seconds
+- **Verification**: 0.5–2 seconds
+
+This is inherent to the algorithm — it trades computation for minimal trust
+assumptions (only SHA-256). The firmware logs a warning before SLH-DSA-128s
+keygen/signing. Users should choose whether to use SLH-DSA-128s per-role
+based on their latency tolerance. ML-DSA-65 is much faster (~100 ms for
+signing on ESP32-S3) and is the recommended PQ signature algorithm for
+interactive use.
+
+### Derivation paths
+
+All algorithms derive from the mnemonic using BIP-32/HMAC-SHA512 with
+SLIP-0010 all-hardened derivation for ed25519/x25519/PQ:
+
+| Algorithm | Path | Notes |
+|---|---|---|
+| secp256k1 (Nostr) | `m/44'/1237'/<n>'/0/0` | NIP-06, existing |
+| ed25519 (SSH) | `m/44'/102001'/<n>'/0'/0'` | SLIP-0010 |
+| x25519 (age) | `m/44'/102002'/<n>'/0'/0'` | SLIP-0010 |
+| ML-DSA-65 | `m/44'/102003'/<n>'/0'/0'` | seed → PQClean keygen |
+| SLH-DSA-128s | `m/44'/102004'/<n>'/0'/0'` | seed → PQClean keygen |
+| ML-KEM-768 | `m/44'/102005'/<n>'/0'/0'` | seed → PQClean keygen |
+
+The PQ derivation produces a 32-byte seed that feeds a deterministic
+SHAKE-256 DRBG ([`pq_drbg_firmware.c`](feather_s3_tft/components/pqclean/pq_drbg_firmware.c)),
+which replaces PQClean's `randombytes()` during keygen. This gives
+deterministic, mnemonic-recoverable PQ keys — same mnemonic, same key pair.
+
+### Firmware API
+
+The firmware exposes PQ operations via [`pq_crypto_firmware.h`](feather_s3_tft/main/pq_crypto_firmware.h):
+
+```c
+/* Key generation (deterministic from mnemonic-derived seed) */
+int fw_pq_ml_dsa_65_keygen(const uint8_t seed[32], uint8_t *pk, uint8_t *sk);
+int fw_pq_slh_dsa_128s_keygen(const uint8_t seed[32], uint8_t *pk, uint8_t *sk);
+int fw_pq_ml_kem_768_keygen(const uint8_t seed[32], uint8_t *pk, uint8_t *sk);
+
+/* Signing / verification */
+int fw_pq_ml_dsa_65_sign(uint8_t *sig, size_t *siglen, ...);
+int fw_pq_slh_dsa_128s_sign(uint8_t *sig, size_t *siglen, ...);
+
+/* KEM encaps / decaps */
+int fw_pq_ml_kem_768_encaps(uint8_t *ct, uint8_t *ss, const uint8_t *pk);
+int fw_pq_ml_kem_768_decaps(uint8_t *ss, const uint8_t *ct, const uint8_t *sk);
+```
+
+Key derivation from the mnemonic seed is via [`key_derivation.h`](feather_s3_tft/main/key_derivation.h):
+
+```c
+int derive_ed25519_key(const uint8_t seed[64], uint32_t index, ...);
+int derive_x25519_key(const uint8_t seed[64], uint32_t index, ...);
+int derive_ml_dsa_65_key(const uint8_t seed[64], uint32_t index, ...);
+int derive_slh_dsa_128s_key(const uint8_t seed[64], uint32_t index, ...);
+int derive_ml_kem_768_key(const uint8_t seed[64], uint32_t index, ...);
+```

firmware/cyd_esp32_2432s028/components/pqclean/CMakeLists.txt

@@ -0,0 +1,60 @@
+# CMakeLists.txt — ESP-IDF component for PQClean post-quantum algorithms.
+#
+# Compiles the three PQ algorithms (ML-DSA-65, SLH-DSA-128s, ML-KEM-768)
+# from the shared resources/pqclean/ source tree, using the mbedtls
+# crypto backend (crypto_backend_mbedtls.c) for SHA-2/SHA3/SHAKE.
+#
+# The source files are referenced via relative paths back to the shared
+# resources/pqclean/ directory so there is a single source of truth.
+#
+# mbedtls requirements:
+#   CONFIG_MBEDTLS_SHA3_C=y  (for SHA3-256, SHA3-512)
+#   CONFIG_MBEDTLS_SHAKE_C=y (for SHAKE-128, SHAKE-256)
+# Enable these in menuconfig under Component config -> mbedTLS ->
+#   Hash functions -> SHA-3 and SHAKE.
+
+set(PQCLEAN_ROOT "${CMAKE_CURRENT_LIST_DIR}/../../../../resources/pqclean")
+
+idf_component_register(
+    SRCS
+        "${PQCLEAN_ROOT}/crypto_sign/ml-dsa-65/sign.c"
+        "${PQCLEAN_ROOT}/crypto_sign/ml-dsa-65/poly.c"
+        "${PQCLEAN_ROOT}/crypto_sign/ml-dsa-65/ntt.c"
+        "${PQCLEAN_ROOT}/crypto_sign/slh-dsa-128s/sign.c"
+        "${PQCLEAN_ROOT}/crypto_sign/slh-dsa-128s/fors.c"
+        "${PQCLEAN_ROOT}/crypto_sign/slh-dsa-128s/wots.c"
+        "${PQCLEAN_ROOT}/crypto_sign/slh-dsa-128s/hash.c"
+        "${PQCLEAN_ROOT}/crypto_sign/slh-dsa-128s/thash.c"
+        "${PQCLEAN_ROOT}/crypto_sign/slh-dsa-128s/address.c"
+        "${PQCLEAN_ROOT}/crypto_sign/slh-dsa-128s/utils.c"
+        "${PQCLEAN_ROOT}/crypto_kem/ml-kem-768/kem.c"
+        "${PQCLEAN_ROOT}/crypto_kem/ml-kem-768/indcpa.c"
+        "${PQCLEAN_ROOT}/crypto_kem/ml-kem-768/poly.c"
+        "${PQCLEAN_ROOT}/crypto_kem/ml-kem-768/ntt.c"
+        "${PQCLEAN_ROOT}/crypto_kem/ml-kem-768/cbd.c"
+        "${PQCLEAN_ROOT}/crypto_kem/ml-kem-768/reduce.c"
+        "${PQCLEAN_ROOT}/crypto_kem/ml-kem-768/symmetric.c"
+        "${PQCLEAN_ROOT}/crypto_kem/ml-kem-768/verify.c"
+        "${PQCLEAN_ROOT}/common/fips202.c"
+        "${PQCLEAN_ROOT}/common/sha2.c"
+        "${PQCLEAN_ROOT}/common/crypto_backend_mbedtls.c"
+        "randombytes_mbedtls.c"
+        "pq_drbg_firmware.c"
+    INCLUDE_DIRS
+        "include"
+        "${PQCLEAN_ROOT}/common"
+        "${PQCLEAN_ROOT}/crypto_sign/ml-dsa-65"
+        "${PQCLEAN_ROOT}/crypto_sign/slh-dsa-128s"
+        "${PQCLEAN_ROOT}/crypto_kem/ml-kem-768"
+    REQUIRES
+        mbedtls
+)
+
+# Suppress warnings from the PQClean code (it uses C99 patterns that
+# trigger -Wextra warnings under ESP-IDF's default flags).
+target_compile_options(${COMPONENT_LIB} PRIVATE
+    -Wno-unused-parameter
+    -Wno-sign-compare
+    -Wno-unused-variable
+    -Wno-unused-but-set-variable
+)

firmware/cyd_esp32_2432s028/components/pqclean/include/ml_dsa_65_api.h

@@ -0,0 +1,5 @@
+/* ml_dsa_65_api.h — firmware wrapper that includes the real PQClean header. */
+#ifndef FIRMWARE_ML_DSA_65_API_WRAPPER_H
+#define FIRMWARE_ML_DSA_65_API_WRAPPER_H
+#include "../../../../resources/pqclean/crypto_sign/ml-dsa-65/api.h"
+#endif

firmware/cyd_esp32_2432s028/components/pqclean/include/ml_kem_768_api.h

@@ -0,0 +1,5 @@
+/* ml_kem_768_api.h — firmware wrapper that includes the real PQClean header. */
+#ifndef FIRMWARE_ML_KEM_768_API_WRAPPER_H
+#define FIRMWARE_ML_KEM_768_API_WRAPPER_H
+#include "../../../../resources/pqclean/crypto_kem/ml-kem-768/api.h"
+#endif

firmware/cyd_esp32_2432s028/components/pqclean/include/pqclean.h

@@ -0,0 +1,38 @@
+/* pqclean.h — Umbrella include for the ESP32 firmware PQClean component.
+ *
+ * Exposes the three post-quantum algorithms (ML-DSA-65, SLH-DSA-128s,
+ * ML-KEM-768) and the deterministic DRBG used for mnemonic-recoverable
+ * key generation.
+ *
+ * On ESP32 the underlying hash/SHAKE primitives are provided by the
+ * mbedtls backend (crypto_backend_mbedtls.c) instead of OpenSSL.
+ */
+#ifndef FIRMWARE_PQCLEAN_H
+#define FIRMWARE_PQCLEAN_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+/* --- ML-DSA-65 (FIPS 204, lattice signatures) --- */
+#include "ml_dsa_65_api.h"
+
+/* --- SLH-DSA-128s (FIPS 205, hash-based signatures) --- */
+#include "slh_dsa_128s_api.h"
+
+/* --- ML-KEM-768 (FIPS 203, lattice KEM) --- */
+#include "ml_kem_768_api.h"
+
+/* --- Deterministic DRBG (replaces randombytes() for keygen) --- */
+/* Initializes the DRBG with a 32-byte mnemonic-derived seed. Subsequent
+ * randombytes() calls will produce a deterministic byte stream. */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+
+/* Zeroizes the DRBG state (call after keygen to wipe sensitive material). */
+void pq_drbg_zeroize(void);
+
+/* randombytes() — called by the PQClean algorithm code.
+ * On firmware this is provided by randombytes_mbedtls.c (deterministic DRBG
+ * for keygen, or mbedtls_ctr_drbg for real randomness during encaps). */
+int randombytes(unsigned char *buf, size_t len);
+
+#endif /* FIRMWARE_PQCLEAN_H */

firmware/cyd_esp32_2432s028/components/pqclean/include/slh_dsa_128s_api.h

@@ -0,0 +1,5 @@
+/* slh_dsa_128s_api.h — firmware wrapper that includes the real PQClean header. */
+#ifndef FIRMWARE_SLH_DSA_128S_API_WRAPPER_H
+#define FIRMWARE_SLH_DSA_128S_API_WRAPPER_H
+#include "../../../../resources/pqclean/crypto_sign/slh-dsa-128s/api.h"
+#endif

firmware/cyd_esp32_2432s028/components/pqclean/pq_drbg_firmware.c

@@ -0,0 +1,108 @@
+/* pq_drbg_firmware.c — Deterministic PRNG for PQ key generation on ESP32.
+ *
+ * Same algorithm as the host's src/pq_drbg.c but uses the crypto backend
+ * abstraction (which resolves to mbedtls on ESP32) for SHAKE-256 instead
+ * of OpenSSL EVP. This allows deterministic PQ key generation from a
+ * mnemonic-derived seed: same seed -> same randombytes output sequence.
+ *
+ * The PRNG: SHAKE-256(seed || counter) produces a stream of pseudo-random
+ * bytes. The counter is a 64-bit little-endian integer that increments
+ * each time we need more output.
+ */
+#include <string.h>
+#include <stdlib.h>
+#include "crypto_backend.h"
+
+/* --- DRBG state --- */
+
+static unsigned char g_seed[32];
+static int g_seed_len = 0;
+static uint64_t g_counter = 0;
+static unsigned char g_buffer[168]; /* SHAKE-256 rate = 136, 168 for safety */
+static size_t g_buffer_pos = sizeof(g_buffer);
+static int g_initialized = 0;
+
+/* --- internal: squeeze more bytes from SHAKE-256 --- */
+
+static void drbg_refill(void) {
+    unsigned char seed_block[32 + 8]; /* seed + counter (8 bytes LE) */
+
+    memcpy(seed_block, g_seed, (size_t)g_seed_len);
+    seed_block[g_seed_len + 0] = (unsigned char)(g_counter & 0xFF);
+    seed_block[g_seed_len + 1] = (unsigned char)((g_counter >> 8) & 0xFF);
+    seed_block[g_seed_len + 2] = (unsigned char)((g_counter >> 16) & 0xFF);
+    seed_block[g_seed_len + 3] = (unsigned char)((g_counter >> 24) & 0xFF);
+    seed_block[g_seed_len + 4] = (unsigned char)((g_counter >> 32) & 0xFF);
+    seed_block[g_seed_len + 5] = (unsigned char)((g_counter >> 40) & 0xFF);
+    seed_block[g_seed_len + 6] = (unsigned char)((g_counter >> 48) & 0xFF);
+    seed_block[g_seed_len + 7] = (unsigned char)((g_counter >> 56) & 0xFF);
+
+    crypto_backend_shake256(seed_block, (size_t)g_seed_len + 8,
+                            g_buffer, sizeof(g_buffer));
+
+    g_counter++;
+    g_buffer_pos = 0;
+}
+
+/* --- public API --- */
+
+void pq_drbg_init(const unsigned char *seed, size_t seed_len) {
+    if (seed == NULL || seed_len == 0) {
+        return;
+    }
+
+    memset(g_seed, 0, sizeof(g_seed));
+    if (seed_len > sizeof(g_seed)) {
+        seed_len = sizeof(g_seed);
+    }
+    memcpy(g_seed, seed, seed_len);
+    g_seed_len = (int)sizeof(g_seed); /* always use 32-byte seed (zero-padded) */
+
+    g_counter = 0;
+    g_buffer_pos = sizeof(g_buffer);
+    g_initialized = 1;
+}
+
+void pq_drbg_zeroize(void) {
+    crypto_backend_cleanse(g_seed, sizeof(g_seed));
+    crypto_backend_cleanse(g_buffer, sizeof(g_buffer));
+    g_seed_len = 0;
+    g_counter = 0;
+    g_buffer_pos = sizeof(g_buffer);
+    g_initialized = 0;
+}
+
+/* Returns 1 if the DRBG has been initialized (keygen mode), 0 otherwise.
+ * Used by randombytes_mbedtls.c to decide between deterministic DRBG and
+ * hardware RNG. */
+int pq_drbg_is_initialized(void) {
+    return g_initialized;
+}
+
+/* pq_drbg_randombytes is called by randombytes() below. */
+int pq_drbg_randombytes(unsigned char *buf, size_t len) {
+    if (buf == NULL || !g_initialized) {
+        return -1;
+    }
+
+    while (len > 0) {
+        size_t avail;
+        size_t to_copy;
+
+        if (g_buffer_pos >= sizeof(g_buffer)) {
+            drbg_refill();
+            if (g_buffer_pos >= sizeof(g_buffer)) {
+                return -1; /* refill failed */
+            }
+        }
+
+        avail = sizeof(g_buffer) - g_buffer_pos;
+        to_copy = (len < avail) ? len : avail;
+        memcpy(buf, g_buffer + g_buffer_pos, to_copy);
+        g_buffer_pos += to_copy;
+        buf += to_copy;
+        len -= to_copy;
+    }
+
+    return 0;
+}

firmware/cyd_esp32_2432s028/components/pqclean/randombytes_mbedtls.c

@@ -0,0 +1,40 @@
+/* randombytes_mbedtls.c — randombytes() implementation for ESP32 firmware.
+ *
+ * PQClean's algorithm code calls randombytes() for:
+ *   1. Key generation (keygen) — must be deterministic from the mnemonic
+ *      seed so keys are recoverable. The DRBG is initialized via
+ *      pq_drbg_init() before keygen, so randombytes() draws from the
+ *      deterministic stream.
+ *   2. Encapsulation (ML-KEM enc) — needs real cryptographic randomness.
+ *      When the DRBG is NOT initialized, randombytes() falls back to
+ *      esp_fill_random() which uses the ESP32 hardware RNG.
+ *
+ * This dual-mode behavior matches the host build (src/pq_drbg.c) where
+ * the DRBG is initialized for keygen and randombytes() returns -1 if
+ * called without initialization. On firmware we allow the fallback to
+ * hardware RNG for encaps, which is the correct behavior.
+ */
+#include <string.h>
+#include "esp_random.h"
+
+/* Defined in pq_drbg_firmware.c */
+extern int pq_drbg_randombytes(unsigned char *buf, size_t len);
+
+/* Check if the DRBG is initialized (declared in pq_drbg_firmware.c).
+ * We use a helper to avoid exposing the static directly. */
+extern int pq_drbg_is_initialized(void);
+
+int randombytes(unsigned char *buf, size_t len) {
+    if (buf == NULL) {
+        return -1;
+    }
+
+    /* If the deterministic DRBG is active (keygen mode), use it. */
+    if (pq_drbg_is_initialized()) {
+        return pq_drbg_randombytes(buf, len);
+    }
+
+    /* Otherwise, use the ESP32 hardware RNG for real randomness (encaps). */
+    esp_fill_random(buf, len);
+    return 0;
+}

firmware/cyd_esp32_2432s028/main/CMakeLists.txt

@@ -10,6 +10,7 @@ idf_component_register(
         "bech32.c"
         "mnemonic.c"
         "key_derivation.c"
+        "pq_crypto_firmware.c"
         "secure_mem.c"
         "../../../resources/nostr_core_lib/nostr_core/nip004.c"
         "../../../resources/nostr_core_lib/nostr_core/nip044.c"
@@ -31,6 +32,7 @@ idf_component_register(
         esp_driver_uart
         mbedtls
         secp256k1
+        pqclean
         json)
 
 target_compile_definitions(${COMPONENT_LIB} PUBLIC LV_CONF_INCLUDE_SIMPLE=1)

firmware/cyd_esp32_2432s028/main/key_derivation.c

@@ -1,17 +1,25 @@
 #include "key_derivation.h"
+#include "pq_crypto_firmware.h"
 
 #include <stddef.h>
 #include <stdint.h>
+#include <stdlib.h>
 #include <string.h>
 
 #include "esp_random.h"
+#include "esp_log.h"
 
 #include "mbedtls/md.h"
+#include "mbedtls/ed25519.h"
+#include "mbedtls/ecp.h"
+#include "mbedtls/pk.h"
 
 #include "secp256k1.h"
 #include "secp256k1_extrakeys.h"
 #include "secp256k1_schnorrsig.h"
 
+static const char *KD_TAG = "key_derivation";
+
 #define BIP32_HARDENED_FLAG 0x80000000u
 
 typedef struct {
@@ -253,3 +261,316 @@ int schnorr_sign32(const uint8_t privkey[32], const uint8_t msg32[32], uint8_t s
     secp256k1_context_destroy(ctx);
     return 0;
 }
+
+/* ====================================================================
+ * Phase 7: ed25519, x25519, and post-quantum key derivation
+ * ==================================================================== */
+
+/* SLIP-0010 all-hardened derivation for ed25519/x25519.
+ *
+ * SLIP-0010 uses HMAC-SHA512 with a "ed25519 seed" or curve-specific key
+ * for the master key, and all derivation steps are hardened (the parent
+ * private key is prepended to the index data).
+ *
+ * For ed25519/x25519, the derived 512-bit HMAC output is split:
+ *   - first 32 bytes = private key (the scalar)
+ *   - last 32 bytes = chain code
+ *
+ * The private key IS the ed25519/x25519 secret — no tweak-add is needed
+ * (unlike secp256k1 BIP-32 where the child priv = parent_priv + HMAC).
+ */
+
+/* SLIP-0010 master key from seed: HMAC-SHA512(key="ed25519 seed", data=seed) */
+static int slip10_master_from_seed(const uint8_t seed[64],
+                                   uint8_t priv[32], uint8_t chain[32]) {
+    static const uint8_t kEd25519Seed[] = "ed25519 seed";
+    uint8_t i64[64] = {0};
+
+    if (hmac_sha512(kEd25519Seed, sizeof(kEd25519Seed) - 1,
+                    seed, 64, i64) != 0) {
+        return -1;
+    }
+
+    memcpy(priv, i64, 32);
+    memcpy(chain, i64 + 32, 32);
+    memset(i64, 0, sizeof(i64));
+    return 0;
+}
+
+/* SLIP-0010 hardened child derivation:
+ * HMAC-SHA512(key=chain, data=0x00 || priv || index_be32) */
+static int slip10_ckd_priv(const uint8_t parent_priv[32],
+                           const uint8_t parent_chain[32],
+                           uint32_t index,
+                           uint8_t child_priv[32],
+                           uint8_t child_chain[32]) {
+    uint8_t data[37];
+    uint8_t i64[64] = {0};
+
+    /* Hardened derivation: 0x00 || priv || index (big-endian) */
+    data[0] = 0x00;
+    memcpy(data + 1, parent_priv, 32);
+    data[33] = (uint8_t)((index >> 24) & 0xFF);
+    data[34] = (uint8_t)((index >> 16) & 0xFF);
+    data[35] = (uint8_t)((index >> 8) & 0xFF);
+    data[36] = (uint8_t)(index & 0xFF);
+
+    if (hmac_sha512(parent_chain, 32, data, sizeof(data), i64) != 0) {
+        memset(data, 0, sizeof(data));
+        return -1;
+    }
+
+    memcpy(child_priv, i64, 32);
+    memcpy(child_chain, i64 + 32, 32);
+    memset(data, 0, sizeof(data));
+    memset(i64, 0, sizeof(i64));
+    return 0;
+}
+
+/* Derive a 32-byte seed via SLIP-0010 all-hardened path.
+ * path[] is an array of hardened indices (the caller sets the hardened flag).
+ * Returns the final 32-byte private material in `out_seed`. */
+static int slip10_derive_seed(const uint8_t seed[64],
+                              const uint32_t *path, size_t path_len,
+                              uint8_t out_seed[32]) {
+    uint8_t priv[32], chain[32], next_priv[32], next_chain[32];
+    size_t i;
+
+    if (slip10_master_from_seed(seed, priv, chain) != 0) {
+        return -1;
+    }
+
+    for (i = 0; i < path_len; i++) {
+        if (slip10_ckd_priv(priv, chain, path[i],
+                            next_priv, next_chain) != 0) {
+            memset(priv, 0, sizeof(priv));
+            memset(chain, 0, sizeof(chain));
+            return -1;
+        }
+        memcpy(priv, next_priv, 32);
+        memcpy(chain, next_chain, 32);
+    }
+
+    memcpy(out_seed, priv, 32);
+    memset(priv, 0, sizeof(priv));
+    memset(chain, 0, sizeof(chain));
+    memset(next_priv, 0, sizeof(next_priv));
+    memset(next_chain, 0, sizeof(next_chain));
+    return 0;
+}
+
+/* --- ed25519 --- */
+
+int derive_ed25519_key(const uint8_t seed[64], uint32_t index,
+                       uint8_t privkey[32], uint8_t pubkey[32]) {
+    /* m/44'/102001'/<index>'/0'/0' — all hardened (SLIP-0010) */
+    const uint32_t path[5] = {
+        44u | BIP32_HARDENED_FLAG,
+        102001u | BIP32_HARDENED_FLAG,
+        index | BIP32_HARDENED_FLAG,
+        0u | BIP32_HARDENED_FLAG,
+        0u | BIP32_HARDENED_FLAG,
+    };
+    uint8_t derived_seed[32];
+
+    if (seed == NULL || privkey == NULL || pubkey == NULL) {
+        return -1;
+    }
+
+    if (slip10_derive_seed(seed, path, 5, derived_seed) != 0) {
+        return -1;
+    }
+
+    /* The SLIP-0010 derived 32 bytes IS the ed25519 private key.
+     * Use mbedtls to derive the public key. */
+    memcpy(privkey, derived_seed, 32);
+
+    /* mbedtls_ed25519_make_public: derive pub from priv */
+    /* Note: mbedtls ed25519 API may vary by version. The ESP-IDF mbedtls
+     * component provides mbedtls_ed25519_make_public (or via the PK API).
+     * We use the low-level function if available. */
+    int ret = mbedtls_ed25519_make_public((unsigned char *)pubkey, 32,
+                                           (const unsigned char *)privkey, 32);
+    if (ret != 0) {
+        ESP_LOGE(KD_TAG, "ed25519 make_public failed: %d", ret);
+        memset(derived_seed, 0, sizeof(derived_seed));
+        memset(privkey, 0, 32);
+        return -1;
+    }
+
+    memset(derived_seed, 0, sizeof(derived_seed));
+    return 0;
+}
+
+int ed25519_sign32(const uint8_t privkey[32], const uint8_t msg32[32],
+                   uint8_t sig64[64]) {
+    /* mbedtls_ed25519_sign: sign a message (not pre-hashed) */
+    int ret = mbedtls_ed25519_sign((unsigned char *)sig64, 64,
+                                    (const unsigned char *)msg32, 32,
+                                    (const unsigned char *)privkey, 32,
+                                    NULL, NULL);
+    if (ret != 0) {
+        ESP_LOGE(KD_TAG, "ed25519 sign failed: %d", ret);
+        return -1;
+    }
+    return 0;
+}
+
+/* --- x25519 --- */
+
+int derive_x25519_key(const uint8_t seed[64], uint32_t index,
+                      uint8_t privkey[32], uint8_t pubkey[32]) {
+    /* m/44'/102002'/<index>'/0'/0' — all hardened (SLIP-0010) */
+    const uint32_t path[5] = {
+        44u | BIP32_HARDENED_FLAG,
+        102002u | BIP32_HARDENED_FLAG,
+        index | BIP32_HARDENED_FLAG,
+        0u | BIP32_HARDENED_FLAG,
+        0u | BIP32_HARDENED_FLAG,
+    };
+    uint8_t derived_seed[32];
+    mbedtls_ecp_group grp;
+    mbedtls_mpi d;
+    mbedtls_ecp_point Q;
+    int ret;
+
+    if (seed == NULL || privkey == NULL || pubkey == NULL) {
+        return -1;
+    }
+
+    if (slip10_derive_seed(seed, path, 5, derived_seed) != 0) {
+        return -1;
+    }
+
+    /* The SLIP-0010 derived 32 bytes IS the x25519 private key.
+     * Clamp it per RFC 7748 and derive the public key via mbedtls ECDH. */
+    memcpy(privkey, derived_seed, 32);
+    memset(derived_seed, 0, sizeof(derived_seed));
+
+    /* x25519 clamping: priv[0] &= 248, priv[31] &= 127, priv[31] |= 64 */
+    privkey[0] &= 248;
+    privkey[31] &= 127;
+    privkey[31] |= 64;
+
+    mbedtls_ecp_group_init(&grp);
+    mbedtls_mpi_init(&d);
+    mbedtls_ecp_point_init(&Q);
+
+    ret = mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_CURVE25519);
+    if (ret != 0) {
+        ESP_LOGE(KD_TAG, "x25519 group load failed: %d", ret);
+        goto cleanup;
+    }
+
+    ret = mbedtls_mpi_read_binary_le(d, privkey, 32);
+    if (ret != 0) {
+        ESP_LOGE(KD_TAG, "x25519 mpi read failed: %d", ret);
+        goto cleanup;
+    }
+
+    ret = mbedtls_ecp_mul(&grp, &Q, d, &grp.G, NULL, NULL);
+    if (ret != 0) {
+        ESP_LOGE(KD_TAG, "x25519 ecp_mul failed: %d", ret);
+        goto cleanup;
+    }
+
+    /* Serialize the public key as raw 32 bytes (little-endian) */
+    {
+        size_t olen = 0;
+        ret = mbedtls_ecp_point_write_binary(&grp, &Q,
+                                              MBEDTLS_ECP_PF_COMPRESSED,
+                                              &olen, pubkey, 32);
+        if (ret != 0 || olen != 32) {
+            ESP_LOGE(KD_TAG, "x25519 pub serialize failed: %d", ret);
+            ret = -1;
+        }
+    }
+
+cleanup:
+    mbedtls_ecp_group_free(&grp);
+    mbedtls_mpi_free(&d);
+    mbedtls_ecp_point_free(&Q);
+    return (ret == 0) ? 0 : -1;
+}
+
+/* --- ML-DSA-65 --- */
+
+int derive_ml_dsa_65_key(const uint8_t seed[64], uint32_t index,
+                         uint8_t *pk, uint8_t *sk) {
+    /* m/44'/102003'/<index>'/0'/0' — all hardened (SLIP-0010) -> 32-byte seed */
+    const uint32_t path[5] = {
+        44u | BIP32_HARDENED_FLAG,
+        102003u | BIP32_HARDENED_FLAG,
+        index | BIP32_HARDENED_FLAG,
+        0u | BIP32_HARDENED_FLAG,
+        0u | BIP32_HARDENED_FLAG,
+    };
+    uint8_t pq_seed[32];
+
+    if (seed == NULL || pk == NULL || sk == NULL) {
+        return -1;
+    }
+
+    if (slip10_derive_seed(seed, path, 5, pq_seed) != 0) {
+        return -1;
+    }
+
+    int ret = fw_pq_ml_dsa_65_keygen(pq_seed, pk, sk);
+    memset(pq_seed, 0, sizeof(pq_seed));
+    return ret;
+}
+
+/* --- SLH-DSA-128s --- */
+
+int derive_slh_dsa_128s_key(const uint8_t seed[64], uint32_t index,
+                            uint8_t *pk, uint8_t *sk) {
+    /* m/44'/102004'/<index>'/0'/0' — all hardened (SLIP-0010) -> 32-byte seed */
+    const uint32_t path[5] = {
+        44u | BIP32_HARDENED_FLAG,
+        102004u | BIP32_HARDENED_FLAG,
+        index | BIP32_HARDENED_FLAG,
+        0u | BIP32_HARDENED_FLAG,
+        0u | BIP32_HARDENED_FLAG,
+    };
+    uint8_t pq_seed[32];
+
+    if (seed == NULL || pk == NULL || sk == NULL) {
+        return -1;
+    }
+
+    if (slip10_derive_seed(seed, path, 5, pq_seed) != 0) {
+        return -1;
+    }
+
+    ESP_LOGW(KD_TAG, "SLH-DSA-128s keygen: this takes 5-30 seconds on ESP32");
+    int ret = fw_pq_slh_dsa_128s_keygen(pq_seed, pk, sk);
+    memset(pq_seed, 0, sizeof(pq_seed));
+    return ret;
+}
+
+/* --- ML-KEM-768 --- */
+
+int derive_ml_kem_768_key(const uint8_t seed[64], uint32_t index,
+                          uint8_t *pk, uint8_t *sk) {
+    /* m/44'/102005'/<index>'/0'/0' — all hardened (SLIP-0010) -> 32-byte seed */
+    const uint32_t path[5] = {
+        44u | BIP32_HARDENED_FLAG,
+        102005u | BIP32_HARDENED_FLAG,
+        index | BIP32_HARDENED_FLAG,
+        0u | BIP32_HARDENED_FLAG,
+        0u | BIP32_HARDENED_FLAG,
+    };
+    uint8_t pq_seed[32];
+
+    if (seed == NULL || pk == NULL || sk == NULL) {
+        return -1;
+    }
+
+    if (slip10_derive_seed(seed, path, 5, pq_seed) != 0) {
+        return -1;
+    }
+
+    int ret = fw_pq_ml_kem_768_keygen(pq_seed, pk, sk);
+    memset(pq_seed, 0, sizeof(pq_seed));
+    return ret;
+}

firmware/cyd_esp32_2432s028/main/key_derivation.h

@@ -1,7 +1,61 @@
 #pragma once
 
+#include <stddef.h>
 #include <stdint.h>
 
+/* --- secp256k1 (Nostr, existing) --- */
 int derive_nostr_key(const uint8_t seed[64], uint8_t privkey[32], uint8_t pubkey[32]);
 int derive_nostr_key_index(const uint8_t seed[64], uint32_t nostr_index, uint8_t privkey[32], uint8_t pubkey[32]);
 int schnorr_sign32(const uint8_t privkey[32], const uint8_t msg32[32], uint8_t sig64[64]);
+
+/* --- ed25519 (SSH signatures) --- */
+/* Derives an ed25519 keypair from the mnemonic seed using SLIP-0010
+ * all-hardened derivation: m/44'/102001'/<n>'/0'/0'
+ * privkey: 32-byte ed25519 private scalar
+ * pubkey:  32-byte ed25519 public key
+ * Returns 0 on success, -1 on error. */
+int derive_ed25519_key(const uint8_t seed[64], uint32_t index,
+                       uint8_t privkey[32], uint8_t pubkey[32]);
+
+/* Signs a 32-byte message digest with ed25519.
+ * sig: 64-byte ed25519 signature
+ * Returns 0 on success, -1 on error. */
+int ed25519_sign32(const uint8_t privkey[32], const uint8_t msg32[32],
+                   uint8_t sig64[64]);
+
+/* --- x25519 (age encryption / key agreement) --- */
+/* Derives an x25519 keypair from the mnemonic seed using SLIP-0010
+ * all-hardened derivation: m/44'/102002'/<n>'/0'/0'
+ * privkey: 32-byte x25519 private scalar
+ * pubkey:  32-byte x25519 public key
+ * Returns 0 on success, -1 on error. */
+int derive_x25519_key(const uint8_t seed[64], uint32_t index,
+                      uint8_t privkey[32], uint8_t pubkey[32]);
+
+/* --- ML-DSA-65 (post-quantum signatures, FIPS 204) --- */
+/* Derives an ML-DSA-65 keypair from the mnemonic seed.
+ * Path: m/44'/102003'/<n>'/0'/0' -> 32-byte seed -> PQClean keygen
+ * pk: FW_ML_DSA_65_PUBKEY_LEN (1952) bytes — caller must allocate
+ * sk: FW_ML_DSA_65_PRIVKEY_LEN (4032) bytes — caller must allocate
+ * Returns 0 on success, -1 on error. */
+int derive_ml_dsa_65_key(const uint8_t seed[64], uint32_t index,
+                         uint8_t *pk, uint8_t *sk);
+
+/* --- SLH-DSA-128s (post-quantum hash-based signatures, FIPS 205) --- */
+/* Derives an SLH-DSA-128s keypair from the mnemonic seed.
+ * Path: m/44'/102004'/<n>'/0'/0' -> 32-byte seed -> PQClean keygen
+ * pk: FW_SLH_DSA_128S_PUBKEY_LEN (32) bytes
+ * sk: FW_SLH_DSA_128S_PRIVKEY_LEN (64) bytes
+ * WARNING: Takes 5-30 seconds on ESP32.
+ * Returns 0 on success, -1 on error. */
+int derive_slh_dsa_128s_key(const uint8_t seed[64], uint32_t index,
+                            uint8_t *pk, uint8_t *sk);
+
+/* --- ML-KEM-768 (post-quantum KEM, FIPS 203) --- */
+/* Derives an ML-KEM-768 keypair from the mnemonic seed.
+ * Path: m/44'/102005'/<n>'/0'/0' -> 32-byte seed -> PQClean keygen
+ * pk: FW_ML_KEM_768_PUBKEY_LEN (1184) bytes — caller must allocate
+ * sk: FW_ML_KEM_768_PRIVKEY_LEN (2400) bytes — caller must allocate
+ * Returns 0 on success, -1 on error. */
+int derive_ml_kem_768_key(const uint8_t seed[64], uint32_t index,
+                          uint8_t *pk, uint8_t *sk);

firmware/cyd_esp32_2432s028/main/pq_crypto_firmware.c

@@ -0,0 +1,171 @@
+/* pq_crypto_firmware.c — Post-quantum crypto wrappers for ESP32 firmware.
+ *
+ * Wraps the PQClean algorithm API (via the pqclean component) with
+ * firmware-friendly functions that handle the deterministic DRBG setup
+ * for keygen and provide clean sign/verify/encaps/decaps interfaces.
+ *
+ * The PQ key buffers are large (ML-DSA-65 priv = 4032 bytes, SLH-DSA-128s
+ * sig = 7856 bytes). Callers must allocate these on the heap or as static
+ * buffers — stack allocation on ESP32 (8KB task stack default) will overflow
+ * for the larger buffers.
+ */
+#include "pq_crypto_firmware.h"
+#include "pqclean.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+/* --- Key generation (deterministic from seed) --- */
+
+int fw_pq_ml_dsa_65_keygen(const uint8_t seed[32],
+                            uint8_t *pk, uint8_t *sk) {
+    if (seed == NULL || pk == NULL || sk == NULL) {
+        return -1;
+    }
+
+    /* Initialize the deterministic DRBG with the mnemonic-derived seed */
+    pq_drbg_init(seed, 32);
+
+    /* Run PQClean keygen — randombytes() draws from the DRBG */
+    int ret = crypto_sign_keypair(pk, sk);
+
+    /* Wipe the DRBG state — the seed material is sensitive */
+    pq_drbg_zeroize();
+
+    return ret;
+}
+
+int fw_pq_slh_dsa_128s_keygen(const uint8_t seed[32],
+                               uint8_t *pk, uint8_t *sk) {
+    if (seed == NULL || pk == NULL || sk == NULL) {
+        return -1;
+    }
+
+    pq_drbg_init(seed, 32);
+
+    /* WARNING: This call takes 5-30 seconds on ESP32 due to the
+     * hypertree construction (7 layers of WOTS+ + Merkle trees). */
+    int ret = slh_dsa_128s_crypto_sign_keypair(pk, sk);
+
+    pq_drbg_zeroize();
+
+    return ret;
+}
+
+int fw_pq_ml_kem_768_keygen(const uint8_t seed[32],
+                             uint8_t *pk, uint8_t *sk) {
+    if (seed == NULL || pk == NULL || sk == NULL) {
+        return -1;
+    }
+
+    pq_drbg_init(seed, 32);
+
+    int ret = crypto_kem_keypair(pk, sk);
+
+    pq_drbg_zeroize();
+
+    return ret;
+}
+
+/* --- Signing --- */
+
+int fw_pq_ml_dsa_65_sign(uint8_t *sig, size_t *siglen,
+                          const uint8_t *m, size_t mlen,
+                          const uint8_t *sk) {
+    if (sig == NULL || siglen == NULL || m == NULL || sk == NULL) {
+        return -1;
+    }
+    return crypto_sign(sig, siglen, m, mlen, sk);
+}
+
+int fw_pq_ml_dsa_65_verify(const uint8_t *sig, size_t siglen,
+                            const uint8_t *m, size_t mlen,
+                            const uint8_t *pk) {
+    if (sig == NULL || m == NULL || pk == NULL) {
+        return -1;
+    }
+    /* crypto_sign_open expects (m_out, mlen_out, sm, smlen, pk) where sm
+     * is the signed message. For detached signatures we reconstruct: the
+     * PQClean API uses crypto_sign_open with sm = sig || m. */
+    /* For firmware use, we provide a simple verify by re-signing is not
+     * possible (non-deterministic). The PQClean crypto_sign_open expects
+     * the concatenated sig||msg format. Callers should use the PQClean
+     * API directly for verification, or we build the sm buffer here. */
+    uint8_t *sm = (uint8_t *)malloc(siglen + mlen);
+    if (sm == NULL) {
+        return -1;
+    }
+    memcpy(sm, sig, siglen);
+    memcpy(sm + siglen, m, mlen);
+
+    uint8_t *m_out = (uint8_t *)malloc(mlen);
+    if (m_out == NULL) {
+        free(sm);
+        return -1;
+    }
+    size_t mlen_out = 0;
+
+    int ret = crypto_sign_open(m_out, &mlen_out, sm, siglen + mlen, pk);
+
+    free(sm);
+    free(m_out);
+
+    return ret;
+}
+
+int fw_pq_slh_dsa_128s_sign(uint8_t *sig, size_t *siglen,
+                              const uint8_t *m, size_t mlen,
+                              const uint8_t *sk) {
+    if (sig == NULL || siglen == NULL || m == NULL || sk == NULL) {
+        return -1;
+    }
+    /* WARNING: This call takes 5-30 seconds on ESP32. */
+    return slh_dsa_128s_crypto_sign(sig, siglen, m, mlen, sk);
+}
+
+int fw_pq_slh_dsa_128s_verify(const uint8_t *sig, size_t siglen,
+                                const uint8_t *m, size_t mlen,
+                                const uint8_t *pk) {
+    if (sig == NULL || m == NULL || pk == NULL) {
+        return -1;
+    }
+    uint8_t *sm = (uint8_t *)malloc(siglen + mlen);
+    if (sm == NULL) {
+        return -1;
+    }
+    memcpy(sm, sig, siglen);
+    memcpy(sm + siglen, m, mlen);
+
+    uint8_t *m_out = (uint8_t *)malloc(mlen);
+    if (m_out == NULL) {
+        free(sm);
+        return -1;
+    }
+    size_t mlen_out = 0;
+
+    int ret = slh_dsa_128s_crypto_sign_open(m_out, &mlen_out, sm,
+                                             siglen + mlen, pk);
+
+    free(sm);
+    free(m_out);
+
+    return ret;
+}
+
+/* --- KEM --- */
+
+int fw_pq_ml_kem_768_encaps(uint8_t *ct, uint8_t *ss, const uint8_t *pk) {
+    if (ct == NULL || ss == NULL || pk == NULL) {
+        return -1;
+    }
+    /* encaps uses real randomness (hardware RNG) — the DRBG is not
+     * initialized, so randombytes() falls back to esp_fill_random(). */
+    return crypto_kem_enc(ct, ss, pk);
+}
+
+int fw_pq_ml_kem_768_decaps(uint8_t *ss, const uint8_t *ct, const uint8_t *sk) {
+    if (ss == NULL || ct == NULL || sk == NULL) {
+        return -1;
+    }
+    return crypto_kem_dec(ss, ct, sk);
+}

firmware/cyd_esp32_2432s028/main/pq_crypto_firmware.h

@@ -0,0 +1,110 @@
+/* pq_crypto_firmware.h — Post-quantum crypto wrappers for ESP32 firmware.
+ *
+ * Provides firmware-friendly wrappers around the PQClean algorithms:
+ *   - ML-DSA-65 (FIPS 204 signatures)
+ *   - SLH-DSA-128s (FIPS 205 hash-based signatures)
+ *   - ML-KEM-768 (FIPS 203 key encapsulation)
+ *
+ * Key generation is deterministic from a 32-byte seed (derived from the
+ * mnemonic via BIP-32/HMAC-SHA512). The seed feeds the deterministic DRBG
+ * (pq_drbg_firmware.c) which replaces PQClean's randombytes() during keygen.
+ *
+ * ed25519 and x25519 are handled separately via mbedtls (see
+ * key_derivation.c) and are not part of this PQClean component.
+ */
+#ifndef FIRMWARE_PQ_CRYPTO_H
+#define FIRMWARE_PQ_CRYPTO_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+/* --- Algorithm identifiers --- */
+typedef enum {
+    FW_PQ_ALG_ML_DSA_65 = 0,
+    FW_PQ_ALG_SLH_DSA_128S,
+    FW_PQ_ALG_ML_KEM_768,
+    FW_PQ_ALG_UNKNOWN
+} fw_pq_alg_t;
+
+/* --- Key sizes (compile-time constants, matching PQClean api.h) --- */
+#define FW_ML_DSA_65_PUBKEY_LEN   1952
+#define FW_ML_DSA_65_PRIVKEY_LEN  4032
+#define FW_ML_DSA_65_SIG_LEN      3309
+
+#define FW_SLH_DSA_128S_PUBKEY_LEN   32
+#define FW_SLH_DSA_128S_PRIVKEY_LEN  64
+#define FW_SLH_DSA_128S_SIG_LEN      7856
+
+#define FW_ML_KEM_768_PUBKEY_LEN      1184
+#define FW_ML_KEM_768_PRIVKEY_LEN     2400
+#define FW_ML_KEM_768_CIPHERTEXT_LEN  1088
+#define FW_ML_KEM_768_SHARED_SECRET_LEN 32
+
+/* --- Key generation (deterministic from seed) --- */
+
+/* Generate an ML-DSA-65 keypair from a 32-byte seed.
+ * pk must be at least FW_ML_DSA_65_PUBKEY_LEN bytes.
+ * sk must be at least FW_ML_DSA_65_PRIVKEY_LEN bytes.
+ * Returns 0 on success, -1 on error. */
+int fw_pq_ml_dsa_65_keygen(const uint8_t seed[32],
+                            uint8_t *pk, uint8_t *sk);
+
+/* Generate an SLH-DSA-128s keypair from a 32-byte seed.
+ * pk must be at least FW_SLH_DSA_128S_PUBKEY_LEN bytes.
+ * sk must be at least FW_SLH_DSA_128S_PRIVKEY_LEN bytes.
+ * Returns 0 on success, -1 on error.
+ * WARNING: SLH-DSA-128s keygen takes 5-30 seconds on ESP32. */
+int fw_pq_slh_dsa_128s_keygen(const uint8_t seed[32],
+                               uint8_t *pk, uint8_t *sk);
+
+/* Generate an ML-KEM-768 keypair from a 32-byte seed.
+ * pk must be at least FW_ML_KEM_768_PUBKEY_LEN bytes.
+ * sk must be at least FW_ML_KEM_768_PRIVKEY_LEN bytes.
+ * Returns 0 on success, -1 on error. */
+int fw_pq_ml_kem_768_keygen(const uint8_t seed[32],
+                             uint8_t *pk, uint8_t *sk);
+
+/* --- Signing (ML-DSA-65, SLH-DSA-128s) --- */
+
+/* Sign a message with ML-DSA-65.
+ * sig must be at least FW_ML_DSA_65_SIG_LEN bytes.
+ * Returns 0 on success, -1 on error. */
+int fw_pq_ml_dsa_65_sign(uint8_t *sig, size_t *siglen,
+                          const uint8_t *m, size_t mlen,
+                          const uint8_t *sk);
+
+/* Verify an ML-DSA-65 signature.
+ * Returns 0 on valid, -1 on invalid. */
+int fw_pq_ml_dsa_65_verify(const uint8_t *sig, size_t siglen,
+                            const uint8_t *m, size_t mlen,
+                            const uint8_t *pk);
+
+/* Sign a message with SLH-DSA-128s.
+ * sig must be at least FW_SLH_DSA_128S_SIG_LEN bytes.
+ * WARNING: SLH-DSA-128s signing takes 5-30 seconds on ESP32.
+ * Returns 0 on success, -1 on error. */
+int fw_pq_slh_dsa_128s_sign(uint8_t *sig, size_t *siglen,
+                              const uint8_t *m, size_t mlen,
+                              const uint8_t *sk);
+
+/* Verify an SLH-DSA-128s signature.
+ * Returns 0 on valid, -1 on invalid. */
+int fw_pq_slh_dsa_128s_verify(const uint8_t *sig, size_t siglen,
+                                const uint8_t *m, size_t mlen,
+                                const uint8_t *pk);
+
+/* --- KEM (ML-KEM-768) --- */
+
+/* Encapsulate: generate ciphertext + shared secret from a public key.
+ * Uses real randomness (ESP32 hardware RNG) — not the deterministic DRBG.
+ * ct must be at least FW_ML_KEM_768_CIPHERTEXT_LEN bytes.
+ * ss must be at least FW_ML_KEM_768_SHARED_SECRET_LEN bytes.
+ * Returns 0 on success, -1 on error. */
+int fw_pq_ml_kem_768_encaps(uint8_t *ct, uint8_t *ss, const uint8_t *pk);
+
+/* Decapsulate: recover shared secret from secret key + ciphertext.
+ * ss must be at least FW_ML_KEM_768_SHARED_SECRET_LEN bytes.
+ * Returns 0 on success, -1 on error. */
+int fw_pq_ml_kem_768_decaps(uint8_t *ss, const uint8_t *ct, const uint8_t *sk);
+
+#endif /* FIRMWARE_PQ_CRYPTO_H */

firmware/feather_s3_tft/components/pqclean/CMakeLists.txt

@@ -0,0 +1,60 @@
+# CMakeLists.txt — ESP-IDF component for PQClean post-quantum algorithms.
+#
+# Compiles the three PQ algorithms (ML-DSA-65, SLH-DSA-128s, ML-KEM-768)
+# from the shared resources/pqclean/ source tree, using the mbedtls
+# crypto backend (crypto_backend_mbedtls.c) for SHA-2/SHA3/SHAKE.
+#
+# The source files are referenced via relative paths back to the shared
+# resources/pqclean/ directory so there is a single source of truth.
+#
+# mbedtls requirements:
+#   CONFIG_MBEDTLS_SHA3_C=y  (for SHA3-256, SHA3-512)
+#   CONFIG_MBEDTLS_SHAKE_C=y (for SHAKE-128, SHAKE-256)
+# Enable these in menuconfig under Component config -> mbedTLS ->
+#   Hash functions -> SHA-3 and SHAKE.
+
+set(PQCLEAN_ROOT "${CMAKE_CURRENT_LIST_DIR}/../../../../resources/pqclean")
+
+idf_component_register(
+    SRCS
+        "${PQCLEAN_ROOT}/crypto_sign/ml-dsa-65/sign.c"
+        "${PQCLEAN_ROOT}/crypto_sign/ml-dsa-65/poly.c"
+        "${PQCLEAN_ROOT}/crypto_sign/ml-dsa-65/ntt.c"
+        "${PQCLEAN_ROOT}/crypto_sign/slh-dsa-128s/sign.c"
+        "${PQCLEAN_ROOT}/crypto_sign/slh-dsa-128s/fors.c"
+        "${PQCLEAN_ROOT}/crypto_sign/slh-dsa-128s/wots.c"
+        "${PQCLEAN_ROOT}/crypto_sign/slh-dsa-128s/hash.c"
+        "${PQCLEAN_ROOT}/crypto_sign/slh-dsa-128s/thash.c"
+        "${PQCLEAN_ROOT}/crypto_sign/slh-dsa-128s/address.c"
+        "${PQCLEAN_ROOT}/crypto_sign/slh-dsa-128s/utils.c"
+        "${PQCLEAN_ROOT}/crypto_kem/ml-kem-768/kem.c"
+        "${PQCLEAN_ROOT}/crypto_kem/ml-kem-768/indcpa.c"
+        "${PQCLEAN_ROOT}/crypto_kem/ml-kem-768/poly.c"
+        "${PQCLEAN_ROOT}/crypto_kem/ml-kem-768/ntt.c"
+        "${PQCLEAN_ROOT}/crypto_kem/ml-kem-768/cbd.c"
+        "${PQCLEAN_ROOT}/crypto_kem/ml-kem-768/reduce.c"
+        "${PQCLEAN_ROOT}/crypto_kem/ml-kem-768/symmetric.c"
+        "${PQCLEAN_ROOT}/crypto_kem/ml-kem-768/verify.c"
+        "${PQCLEAN_ROOT}/common/fips202.c"
+        "${PQCLEAN_ROOT}/common/sha2.c"
+        "${PQCLEAN_ROOT}/common/crypto_backend_mbedtls.c"
+        "randombytes_mbedtls.c"
+        "pq_drbg_firmware.c"
+    INCLUDE_DIRS
+        "include"
+        "${PQCLEAN_ROOT}/common"
+        "${PQCLEAN_ROOT}/crypto_sign/ml-dsa-65"
+        "${PQCLEAN_ROOT}/crypto_sign/slh-dsa-128s"
+        "${PQCLEAN_ROOT}/crypto_kem/ml-kem-768"
+    REQUIRES
+        mbedtls
+)
+
+# Suppress warnings from the PQClean code (it uses C99 patterns that
+# trigger -Wextra warnings under ESP-IDF's default flags).
+target_compile_options(${COMPONENT_LIB} PRIVATE
+    -Wno-unused-parameter
+    -Wno-sign-compare
+    -Wno-unused-variable
+    -Wno-unused-but-set-variable
+)

firmware/feather_s3_tft/components/pqclean/include/ml_dsa_65_api.h

@@ -0,0 +1,5 @@
+/* ml_dsa_65_api.h — firmware wrapper that includes the real PQClean header. */
+#ifndef FIRMWARE_ML_DSA_65_API_WRAPPER_H
+#define FIRMWARE_ML_DSA_65_API_WRAPPER_H
+#include "../../../../resources/pqclean/crypto_sign/ml-dsa-65/api.h"
+#endif

firmware/feather_s3_tft/components/pqclean/include/ml_kem_768_api.h

@@ -0,0 +1,5 @@
+/* ml_kem_768_api.h — firmware wrapper that includes the real PQClean header. */
+#ifndef FIRMWARE_ML_KEM_768_API_WRAPPER_H
+#define FIRMWARE_ML_KEM_768_API_WRAPPER_H
+#include "../../../../resources/pqclean/crypto_kem/ml-kem-768/api.h"
+#endif

firmware/feather_s3_tft/components/pqclean/include/pqclean.h

@@ -0,0 +1,38 @@
+/* pqclean.h — Umbrella include for the ESP32 firmware PQClean component.
+ *
+ * Exposes the three post-quantum algorithms (ML-DSA-65, SLH-DSA-128s,
+ * ML-KEM-768) and the deterministic DRBG used for mnemonic-recoverable
+ * key generation.
+ *
+ * On ESP32 the underlying hash/SHAKE primitives are provided by the
+ * mbedtls backend (crypto_backend_mbedtls.c) instead of OpenSSL.
+ */
+#ifndef FIRMWARE_PQCLEAN_H
+#define FIRMWARE_PQCLEAN_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+/* --- ML-DSA-65 (FIPS 204, lattice signatures) --- */
+#include "ml_dsa_65_api.h"
+
+/* --- SLH-DSA-128s (FIPS 205, hash-based signatures) --- */
+#include "slh_dsa_128s_api.h"
+
+/* --- ML-KEM-768 (FIPS 203, lattice KEM) --- */
+#include "ml_kem_768_api.h"
+
+/* --- Deterministic DRBG (replaces randombytes() for keygen) --- */
+/* Initializes the DRBG with a 32-byte mnemonic-derived seed. Subsequent
+ * randombytes() calls will produce a deterministic byte stream. */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+
+/* Zeroizes the DRBG state (call after keygen to wipe sensitive material). */
+void pq_drbg_zeroize(void);
+
+/* randombytes() — called by the PQClean algorithm code.
+ * On firmware this is provided by randombytes_mbedtls.c (deterministic DRBG
+ * for keygen, or mbedtls_ctr_drbg for real randomness during encaps). */
+int randombytes(unsigned char *buf, size_t len);
+
+#endif /* FIRMWARE_PQCLEAN_H */

firmware/feather_s3_tft/components/pqclean/include/slh_dsa_128s_api.h

@@ -0,0 +1,5 @@
+/* slh_dsa_128s_api.h — firmware wrapper that includes the real PQClean header. */
+#ifndef FIRMWARE_SLH_DSA_128S_API_WRAPPER_H
+#define FIRMWARE_SLH_DSA_128S_API_WRAPPER_H
+#include "../../../../resources/pqclean/crypto_sign/slh-dsa-128s/api.h"
+#endif

firmware/feather_s3_tft/components/pqclean/pq_drbg_firmware.c

@@ -0,0 +1,108 @@
+/* pq_drbg_firmware.c — Deterministic PRNG for PQ key generation on ESP32.
+ *
+ * Same algorithm as the host's src/pq_drbg.c but uses the crypto backend
+ * abstraction (which resolves to mbedtls on ESP32) for SHAKE-256 instead
+ * of OpenSSL EVP. This allows deterministic PQ key generation from a
+ * mnemonic-derived seed: same seed -> same randombytes output sequence.
+ *
+ * The PRNG: SHAKE-256(seed || counter) produces a stream of pseudo-random
+ * bytes. The counter is a 64-bit little-endian integer that increments
+ * each time we need more output.
+ */
+#include <string.h>
+#include <stdlib.h>
+#include "crypto_backend.h"
+
+/* --- DRBG state --- */
+
+static unsigned char g_seed[32];
+static int g_seed_len = 0;
+static uint64_t g_counter = 0;
+static unsigned char g_buffer[168]; /* SHAKE-256 rate = 136, 168 for safety */
+static size_t g_buffer_pos = sizeof(g_buffer);
+static int g_initialized = 0;
+
+/* --- internal: squeeze more bytes from SHAKE-256 --- */
+
+static void drbg_refill(void) {
+    unsigned char seed_block[32 + 8]; /* seed + counter (8 bytes LE) */
+
+    memcpy(seed_block, g_seed, (size_t)g_seed_len);
+    seed_block[g_seed_len + 0] = (unsigned char)(g_counter & 0xFF);
+    seed_block[g_seed_len + 1] = (unsigned char)((g_counter >> 8) & 0xFF);
+    seed_block[g_seed_len + 2] = (unsigned char)((g_counter >> 16) & 0xFF);
+    seed_block[g_seed_len + 3] = (unsigned char)((g_counter >> 24) & 0xFF);
+    seed_block[g_seed_len + 4] = (unsigned char)((g_counter >> 32) & 0xFF);
+    seed_block[g_seed_len + 5] = (unsigned char)((g_counter >> 40) & 0xFF);
+    seed_block[g_seed_len + 6] = (unsigned char)((g_counter >> 48) & 0xFF);
+    seed_block[g_seed_len + 7] = (unsigned char)((g_counter >> 56) & 0xFF);
+
+    crypto_backend_shake256(seed_block, (size_t)g_seed_len + 8,
+                            g_buffer, sizeof(g_buffer));
+
+    g_counter++;
+    g_buffer_pos = 0;
+}
+
+/* --- public API --- */
+
+void pq_drbg_init(const unsigned char *seed, size_t seed_len) {
+    if (seed == NULL || seed_len == 0) {
+        return;
+    }
+
+    memset(g_seed, 0, sizeof(g_seed));
+    if (seed_len > sizeof(g_seed)) {
+        seed_len = sizeof(g_seed);
+    }
+    memcpy(g_seed, seed, seed_len);
+    g_seed_len = (int)sizeof(g_seed); /* always use 32-byte seed (zero-padded) */
+
+    g_counter = 0;
+    g_buffer_pos = sizeof(g_buffer);
+    g_initialized = 1;
+}
+
+void pq_drbg_zeroize(void) {
+    crypto_backend_cleanse(g_seed, sizeof(g_seed));
+    crypto_backend_cleanse(g_buffer, sizeof(g_buffer));
+    g_seed_len = 0;
+    g_counter = 0;
+    g_buffer_pos = sizeof(g_buffer);
+    g_initialized = 0;
+}
+
+/* Returns 1 if the DRBG has been initialized (keygen mode), 0 otherwise.
+ * Used by randombytes_mbedtls.c to decide between deterministic DRBG and
+ * hardware RNG. */
+int pq_drbg_is_initialized(void) {
+    return g_initialized;
+}
+
+/* pq_drbg_randombytes is called by randombytes() below. */
+int pq_drbg_randombytes(unsigned char *buf, size_t len) {
+    if (buf == NULL || !g_initialized) {
+        return -1;
+    }
+
+    while (len > 0) {
+        size_t avail;
+        size_t to_copy;
+
+        if (g_buffer_pos >= sizeof(g_buffer)) {
+            drbg_refill();
+            if (g_buffer_pos >= sizeof(g_buffer)) {
+                return -1; /* refill failed */
+            }
+        }
+
+        avail = sizeof(g_buffer) - g_buffer_pos;
+        to_copy = (len < avail) ? len : avail;
+        memcpy(buf, g_buffer + g_buffer_pos, to_copy);
+        g_buffer_pos += to_copy;
+        buf += to_copy;
+        len -= to_copy;
+    }
+
+    return 0;
+}

firmware/feather_s3_tft/components/pqclean/randombytes_mbedtls.c

@@ -0,0 +1,40 @@
+/* randombytes_mbedtls.c — randombytes() implementation for ESP32 firmware.
+ *
+ * PQClean's algorithm code calls randombytes() for:
+ *   1. Key generation (keygen) — must be deterministic from the mnemonic
+ *      seed so keys are recoverable. The DRBG is initialized via
+ *      pq_drbg_init() before keygen, so randombytes() draws from the
+ *      deterministic stream.
+ *   2. Encapsulation (ML-KEM enc) — needs real cryptographic randomness.
+ *      When the DRBG is NOT initialized, randombytes() falls back to
+ *      esp_fill_random() which uses the ESP32 hardware RNG.
+ *
+ * This dual-mode behavior matches the host build (src/pq_drbg.c) where
+ * the DRBG is initialized for keygen and randombytes() returns -1 if
+ * called without initialization. On firmware we allow the fallback to
+ * hardware RNG for encaps, which is the correct behavior.
+ */
+#include <string.h>
+#include "esp_random.h"
+
+/* Defined in pq_drbg_firmware.c */
+extern int pq_drbg_randombytes(unsigned char *buf, size_t len);
+
+/* Check if the DRBG is initialized (declared in pq_drbg_firmware.c).
+ * We use a helper to avoid exposing the static directly. */
+extern int pq_drbg_is_initialized(void);
+
+int randombytes(unsigned char *buf, size_t len) {
+    if (buf == NULL) {
+        return -1;
+    }
+
+    /* If the deterministic DRBG is active (keygen mode), use it. */
+    if (pq_drbg_is_initialized()) {
+        return pq_drbg_randombytes(buf, len);
+    }
+
+    /* Otherwise, use the ESP32 hardware RNG for real randomness (encaps). */
+    esp_fill_random(buf, len);
+    return 0;
+}

firmware/feather_s3_tft/main/CMakeLists.txt

@@ -4,6 +4,7 @@ idf_component_register(
         "display.c"
         "mnemonic.c"
         "key_derivation.c"
+        "pq_crypto_firmware.c"
         "bech32.c"
         "usb_transport.c"
         "buttons.c"
@@ -23,6 +24,7 @@ idf_component_register(
     REQUIRES
         mbedtls
         secp256k1
+        pqclean
         json
         espressif__esp_tinyusb
         espressif__tinyusb

firmware/feather_s3_tft/main/key_derivation.c

@@ -1,17 +1,25 @@
 #include "key_derivation.h"
+#include "pq_crypto_firmware.h"
 
 #include <stddef.h>
 #include <stdint.h>
+#include <stdlib.h>
 #include <string.h>
 
 #include "esp_random.h"
+#include "esp_log.h"
 
 #include "mbedtls/md.h"
+#include "mbedtls/ed25519.h"
+#include "mbedtls/ecp.h"
+#include "mbedtls/pk.h"
 
 #include "secp256k1.h"
 #include "secp256k1_extrakeys.h"
 #include "secp256k1_schnorrsig.h"
 
+static const char *KD_TAG = "key_derivation";
+
 #define BIP32_HARDENED_FLAG 0x80000000u
 
 typedef struct {
@@ -253,3 +261,316 @@ int schnorr_sign32(const uint8_t privkey[32], const uint8_t msg32[32], uint8_t s
     secp256k1_context_destroy(ctx);
     return 0;
 }
+
+/* ====================================================================
+ * Phase 7: ed25519, x25519, and post-quantum key derivation
+ * ==================================================================== */
+
+/* SLIP-0010 all-hardened derivation for ed25519/x25519.
+ *
+ * SLIP-0010 uses HMAC-SHA512 with a "ed25519 seed" or curve-specific key
+ * for the master key, and all derivation steps are hardened (the parent
+ * private key is prepended to the index data).
+ *
+ * For ed25519/x25519, the derived 512-bit HMAC output is split:
+ *   - first 32 bytes = private key (the scalar)
+ *   - last 32 bytes = chain code
+ *
+ * The private key IS the ed25519/x25519 secret — no tweak-add is needed
+ * (unlike secp256k1 BIP-32 where the child priv = parent_priv + HMAC).
+ */
+
+/* SLIP-0010 master key from seed: HMAC-SHA512(key="ed25519 seed", data=seed) */
+static int slip10_master_from_seed(const uint8_t seed[64],
+                                   uint8_t priv[32], uint8_t chain[32]) {
+    static const uint8_t kEd25519Seed[] = "ed25519 seed";
+    uint8_t i64[64] = {0};
+
+    if (hmac_sha512(kEd25519Seed, sizeof(kEd25519Seed) - 1,
+                    seed, 64, i64) != 0) {
+        return -1;
+    }
+
+    memcpy(priv, i64, 32);
+    memcpy(chain, i64 + 32, 32);
+    memset(i64, 0, sizeof(i64));
+    return 0;
+}
+
+/* SLIP-0010 hardened child derivation:
+ * HMAC-SHA512(key=chain, data=0x00 || priv || index_be32) */
+static int slip10_ckd_priv(const uint8_t parent_priv[32],
+                           const uint8_t parent_chain[32],
+                           uint32_t index,
+                           uint8_t child_priv[32],
+                           uint8_t child_chain[32]) {
+    uint8_t data[37];
+    uint8_t i64[64] = {0};
+
+    /* Hardened derivation: 0x00 || priv || index (big-endian) */
+    data[0] = 0x00;
+    memcpy(data + 1, parent_priv, 32);
+    data[33] = (uint8_t)((index >> 24) & 0xFF);
+    data[34] = (uint8_t)((index >> 16) & 0xFF);
+    data[35] = (uint8_t)((index >> 8) & 0xFF);
+    data[36] = (uint8_t)(index & 0xFF);
+
+    if (hmac_sha512(parent_chain, 32, data, sizeof(data), i64) != 0) {
+        memset(data, 0, sizeof(data));
+        return -1;
+    }
+
+    memcpy(child_priv, i64, 32);
+    memcpy(child_chain, i64 + 32, 32);
+    memset(data, 0, sizeof(data));
+    memset(i64, 0, sizeof(i64));
+    return 0;
+}
+
+/* Derive a 32-byte seed via SLIP-0010 all-hardened path.
+ * path[] is an array of hardened indices (the caller sets the hardened flag).
+ * Returns the final 32-byte private material in `out_seed`. */
+static int slip10_derive_seed(const uint8_t seed[64],
+                              const uint32_t *path, size_t path_len,
+                              uint8_t out_seed[32]) {
+    uint8_t priv[32], chain[32], next_priv[32], next_chain[32];
+    size_t i;
+
+    if (slip10_master_from_seed(seed, priv, chain) != 0) {
+        return -1;
+    }
+
+    for (i = 0; i < path_len; i++) {
+        if (slip10_ckd_priv(priv, chain, path[i],
+                            next_priv, next_chain) != 0) {
+            memset(priv, 0, sizeof(priv));
+            memset(chain, 0, sizeof(chain));
+            return -1;
+        }
+        memcpy(priv, next_priv, 32);
+        memcpy(chain, next_chain, 32);
+    }
+
+    memcpy(out_seed, priv, 32);
+    memset(priv, 0, sizeof(priv));
+    memset(chain, 0, sizeof(chain));
+    memset(next_priv, 0, sizeof(next_priv));
+    memset(next_chain, 0, sizeof(next_chain));
+    return 0;
+}
+
+/* --- ed25519 --- */
+
+int derive_ed25519_key(const uint8_t seed[64], uint32_t index,
+                       uint8_t privkey[32], uint8_t pubkey[32]) {
+    /* m/44'/102001'/<index>'/0'/0' — all hardened (SLIP-0010) */
+    const uint32_t path[5] = {
+        44u | BIP32_HARDENED_FLAG,
+        102001u | BIP32_HARDENED_FLAG,
+        index | BIP32_HARDENED_FLAG,
+        0u | BIP32_HARDENED_FLAG,
+        0u | BIP32_HARDENED_FLAG,
+    };
+    uint8_t derived_seed[32];
+
+    if (seed == NULL || privkey == NULL || pubkey == NULL) {
+        return -1;
+    }
+
+    if (slip10_derive_seed(seed, path, 5, derived_seed) != 0) {
+        return -1;
+    }
+
+    /* The SLIP-0010 derived 32 bytes IS the ed25519 private key.
+     * Use mbedtls to derive the public key. */
+    memcpy(privkey, derived_seed, 32);
+
+    /* mbedtls_ed25519_make_public: derive pub from priv */
+    /* Note: mbedtls ed25519 API may vary by version. The ESP-IDF mbedtls
+     * component provides mbedtls_ed25519_make_public (or via the PK API).
+     * We use the low-level function if available. */
+    int ret = mbedtls_ed25519_make_public((unsigned char *)pubkey, 32,
+                                           (const unsigned char *)privkey, 32);
+    if (ret != 0) {
+        ESP_LOGE(KD_TAG, "ed25519 make_public failed: %d", ret);
+        memset(derived_seed, 0, sizeof(derived_seed));
+        memset(privkey, 0, 32);
+        return -1;
+    }
+
+    memset(derived_seed, 0, sizeof(derived_seed));
+    return 0;
+}
+
+int ed25519_sign32(const uint8_t privkey[32], const uint8_t msg32[32],
+                   uint8_t sig64[64]) {
+    /* mbedtls_ed25519_sign: sign a message (not pre-hashed) */
+    int ret = mbedtls_ed25519_sign((unsigned char *)sig64, 64,
+                                    (const unsigned char *)msg32, 32,
+                                    (const unsigned char *)privkey, 32,
+                                    NULL, NULL);
+    if (ret != 0) {
+        ESP_LOGE(KD_TAG, "ed25519 sign failed: %d", ret);
+        return -1;
+    }
+    return 0;
+}
+
+/* --- x25519 --- */
+
+int derive_x25519_key(const uint8_t seed[64], uint32_t index,
+                      uint8_t privkey[32], uint8_t pubkey[32]) {
+    /* m/44'/102002'/<index>'/0'/0' — all hardened (SLIP-0010) */
+    const uint32_t path[5] = {
+        44u | BIP32_HARDENED_FLAG,
+        102002u | BIP32_HARDENED_FLAG,
+        index | BIP32_HARDENED_FLAG,
+        0u | BIP32_HARDENED_FLAG,
+        0u | BIP32_HARDENED_FLAG,
+    };
+    uint8_t derived_seed[32];
+    mbedtls_ecp_group grp;
+    mbedtls_mpi d;
+    mbedtls_ecp_point Q;
+    int ret;
+
+    if (seed == NULL || privkey == NULL || pubkey == NULL) {
+        return -1;
+    }
+
+    if (slip10_derive_seed(seed, path, 5, derived_seed) != 0) {
+        return -1;
+    }
+
+    /* The SLIP-0010 derived 32 bytes IS the x25519 private key.
+     * Clamp it per RFC 7748 and derive the public key via mbedtls ECDH. */
+    memcpy(privkey, derived_seed, 32);
+    memset(derived_seed, 0, sizeof(derived_seed));
+
+    /* x25519 clamping: priv[0] &= 248, priv[31] &= 127, priv[31] |= 64 */
+    privkey[0] &= 248;
+    privkey[31] &= 127;
+    privkey[31] |= 64;
+
+    mbedtls_ecp_group_init(&grp);
+    mbedtls_mpi_init(&d);
+    mbedtls_ecp_point_init(&Q);
+
+    ret = mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_CURVE25519);
+    if (ret != 0) {
+        ESP_LOGE(KD_TAG, "x25519 group load failed: %d", ret);
+        goto cleanup;
+    }
+
+    ret = mbedtls_mpi_read_binary_le(d, privkey, 32);
+    if (ret != 0) {
+        ESP_LOGE(KD_TAG, "x25519 mpi read failed: %d", ret);
+        goto cleanup;
+    }
+
+    ret = mbedtls_ecp_mul(&grp, &Q, d, &grp.G, NULL, NULL);
+    if (ret != 0) {
+        ESP_LOGE(KD_TAG, "x25519 ecp_mul failed: %d", ret);
+        goto cleanup;
+    }
+
+    /* Serialize the public key as raw 32 bytes (little-endian) */
+    {
+        size_t olen = 0;
+        ret = mbedtls_ecp_point_write_binary(&grp, &Q,
+                                              MBEDTLS_ECP_PF_COMPRESSED,
+                                              &olen, pubkey, 32);
+        if (ret != 0 || olen != 32) {
+            ESP_LOGE(KD_TAG, "x25519 pub serialize failed: %d", ret);
+            ret = -1;
+        }
+    }
+
+cleanup:
+    mbedtls_ecp_group_free(&grp);
+    mbedtls_mpi_free(&d);
+    mbedtls_ecp_point_free(&Q);
+    return (ret == 0) ? 0 : -1;
+}
+
+/* --- ML-DSA-65 --- */
+
+int derive_ml_dsa_65_key(const uint8_t seed[64], uint32_t index,
+                         uint8_t *pk, uint8_t *sk) {
+    /* m/44'/102003'/<index>'/0'/0' — all hardened (SLIP-0010) -> 32-byte seed */
+    const uint32_t path[5] = {
+        44u | BIP32_HARDENED_FLAG,
+        102003u | BIP32_HARDENED_FLAG,
+        index | BIP32_HARDENED_FLAG,
+        0u | BIP32_HARDENED_FLAG,
+        0u | BIP32_HARDENED_FLAG,
+    };
+    uint8_t pq_seed[32];
+
+    if (seed == NULL || pk == NULL || sk == NULL) {
+        return -1;
+    }
+
+    if (slip10_derive_seed(seed, path, 5, pq_seed) != 0) {
+        return -1;
+    }
+
+    int ret = fw_pq_ml_dsa_65_keygen(pq_seed, pk, sk);
+    memset(pq_seed, 0, sizeof(pq_seed));
+    return ret;
+}
+
+/* --- SLH-DSA-128s --- */
+
+int derive_slh_dsa_128s_key(const uint8_t seed[64], uint32_t index,
+                            uint8_t *pk, uint8_t *sk) {
+    /* m/44'/102004'/<index>'/0'/0' — all hardened (SLIP-0010) -> 32-byte seed */
+    const uint32_t path[5] = {
+        44u | BIP32_HARDENED_FLAG,
+        102004u | BIP32_HARDENED_FLAG,
+        index | BIP32_HARDENED_FLAG,
+        0u | BIP32_HARDENED_FLAG,
+        0u | BIP32_HARDENED_FLAG,
+    };
+    uint8_t pq_seed[32];
+
+    if (seed == NULL || pk == NULL || sk == NULL) {
+        return -1;
+    }
+
+    if (slip10_derive_seed(seed, path, 5, pq_seed) != 0) {
+        return -1;
+    }
+
+    ESP_LOGW(KD_TAG, "SLH-DSA-128s keygen: this takes 5-30 seconds on ESP32");
+    int ret = fw_pq_slh_dsa_128s_keygen(pq_seed, pk, sk);
+    memset(pq_seed, 0, sizeof(pq_seed));
+    return ret;
+}
+
+/* --- ML-KEM-768 --- */
+
+int derive_ml_kem_768_key(const uint8_t seed[64], uint32_t index,
+                          uint8_t *pk, uint8_t *sk) {
+    /* m/44'/102005'/<index>'/0'/0' — all hardened (SLIP-0010) -> 32-byte seed */
+    const uint32_t path[5] = {
+        44u | BIP32_HARDENED_FLAG,
+        102005u | BIP32_HARDENED_FLAG,
+        index | BIP32_HARDENED_FLAG,
+        0u | BIP32_HARDENED_FLAG,
+        0u | BIP32_HARDENED_FLAG,
+    };
+    uint8_t pq_seed[32];
+
+    if (seed == NULL || pk == NULL || sk == NULL) {
+        return -1;
+    }
+
+    if (slip10_derive_seed(seed, path, 5, pq_seed) != 0) {
+        return -1;
+    }
+
+    int ret = fw_pq_ml_kem_768_keygen(pq_seed, pk, sk);
+    memset(pq_seed, 0, sizeof(pq_seed));
+    return ret;
+}

firmware/feather_s3_tft/main/key_derivation.h

@@ -1,7 +1,61 @@
 #pragma once
 
+#include <stddef.h>
 #include <stdint.h>
 
+/* --- secp256k1 (Nostr, existing) --- */
 int derive_nostr_key(const uint8_t seed[64], uint8_t privkey[32], uint8_t pubkey[32]);
 int derive_nostr_key_index(const uint8_t seed[64], uint32_t nostr_index, uint8_t privkey[32], uint8_t pubkey[32]);
 int schnorr_sign32(const uint8_t privkey[32], const uint8_t msg32[32], uint8_t sig64[64]);
+
+/* --- ed25519 (SSH signatures) --- */
+/* Derives an ed25519 keypair from the mnemonic seed using SLIP-0010
+ * all-hardened derivation: m/44'/102001'/<n>'/0'/0'
+ * privkey: 32-byte ed25519 private scalar
+ * pubkey:  32-byte ed25519 public key
+ * Returns 0 on success, -1 on error. */
+int derive_ed25519_key(const uint8_t seed[64], uint32_t index,
+                       uint8_t privkey[32], uint8_t pubkey[32]);
+
+/* Signs a 32-byte message digest with ed25519.
+ * sig: 64-byte ed25519 signature
+ * Returns 0 on success, -1 on error. */
+int ed25519_sign32(const uint8_t privkey[32], const uint8_t msg32[32],
+                   uint8_t sig64[64]);
+
+/* --- x25519 (age encryption / key agreement) --- */
+/* Derives an x25519 keypair from the mnemonic seed using SLIP-0010
+ * all-hardened derivation: m/44'/102002'/<n>'/0'/0'
+ * privkey: 32-byte x25519 private scalar
+ * pubkey:  32-byte x25519 public key
+ * Returns 0 on success, -1 on error. */
+int derive_x25519_key(const uint8_t seed[64], uint32_t index,
+                      uint8_t privkey[32], uint8_t pubkey[32]);
+
+/* --- ML-DSA-65 (post-quantum signatures, FIPS 204) --- */
+/* Derives an ML-DSA-65 keypair from the mnemonic seed.
+ * Path: m/44'/102003'/<n>'/0'/0' -> 32-byte seed -> PQClean keygen
+ * pk: FW_ML_DSA_65_PUBKEY_LEN (1952) bytes — caller must allocate
+ * sk: FW_ML_DSA_65_PRIVKEY_LEN (4032) bytes — caller must allocate
+ * Returns 0 on success, -1 on error. */
+int derive_ml_dsa_65_key(const uint8_t seed[64], uint32_t index,
+                         uint8_t *pk, uint8_t *sk);
+
+/* --- SLH-DSA-128s (post-quantum hash-based signatures, FIPS 205) --- */
+/* Derives an SLH-DSA-128s keypair from the mnemonic seed.
+ * Path: m/44'/102004'/<n>'/0'/0' -> 32-byte seed -> PQClean keygen
+ * pk: FW_SLH_DSA_128S_PUBKEY_LEN (32) bytes
+ * sk: FW_SLH_DSA_128S_PRIVKEY_LEN (64) bytes
+ * WARNING: Takes 5-30 seconds on ESP32.
+ * Returns 0 on success, -1 on error. */
+int derive_slh_dsa_128s_key(const uint8_t seed[64], uint32_t index,
+                            uint8_t *pk, uint8_t *sk);
+
+/* --- ML-KEM-768 (post-quantum KEM, FIPS 203) --- */
+/* Derives an ML-KEM-768 keypair from the mnemonic seed.
+ * Path: m/44'/102005'/<n>'/0'/0' -> 32-byte seed -> PQClean keygen
+ * pk: FW_ML_KEM_768_PUBKEY_LEN (1184) bytes — caller must allocate
+ * sk: FW_ML_KEM_768_PRIVKEY_LEN (2400) bytes — caller must allocate
+ * Returns 0 on success, -1 on error. */
+int derive_ml_kem_768_key(const uint8_t seed[64], uint32_t index,
+                          uint8_t *pk, uint8_t *sk);

firmware/feather_s3_tft/main/pq_crypto_firmware.c

@@ -0,0 +1,171 @@
+/* pq_crypto_firmware.c — Post-quantum crypto wrappers for ESP32 firmware.
+ *
+ * Wraps the PQClean algorithm API (via the pqclean component) with
+ * firmware-friendly functions that handle the deterministic DRBG setup
+ * for keygen and provide clean sign/verify/encaps/decaps interfaces.
+ *
+ * The PQ key buffers are large (ML-DSA-65 priv = 4032 bytes, SLH-DSA-128s
+ * sig = 7856 bytes). Callers must allocate these on the heap or as static
+ * buffers — stack allocation on ESP32 (8KB task stack default) will overflow
+ * for the larger buffers.
+ */
+#include "pq_crypto_firmware.h"
+#include "pqclean.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+/* --- Key generation (deterministic from seed) --- */
+
+int fw_pq_ml_dsa_65_keygen(const uint8_t seed[32],
+                            uint8_t *pk, uint8_t *sk) {
+    if (seed == NULL || pk == NULL || sk == NULL) {
+        return -1;
+    }
+
+    /* Initialize the deterministic DRBG with the mnemonic-derived seed */
+    pq_drbg_init(seed, 32);
+
+    /* Run PQClean keygen — randombytes() draws from the DRBG */
+    int ret = crypto_sign_keypair(pk, sk);
+
+    /* Wipe the DRBG state — the seed material is sensitive */
+    pq_drbg_zeroize();
+
+    return ret;
+}
+
+int fw_pq_slh_dsa_128s_keygen(const uint8_t seed[32],
+                               uint8_t *pk, uint8_t *sk) {
+    if (seed == NULL || pk == NULL || sk == NULL) {
+        return -1;
+    }
+
+    pq_drbg_init(seed, 32);
+
+    /* WARNING: This call takes 5-30 seconds on ESP32 due to the
+     * hypertree construction (7 layers of WOTS+ + Merkle trees). */
+    int ret = slh_dsa_128s_crypto_sign_keypair(pk, sk);
+
+    pq_drbg_zeroize();
+
+    return ret;
+}
+
+int fw_pq_ml_kem_768_keygen(const uint8_t seed[32],
+                             uint8_t *pk, uint8_t *sk) {
+    if (seed == NULL || pk == NULL || sk == NULL) {
+        return -1;
+    }
+
+    pq_drbg_init(seed, 32);
+
+    int ret = crypto_kem_keypair(pk, sk);
+
+    pq_drbg_zeroize();
+
+    return ret;
+}
+
+/* --- Signing --- */
+
+int fw_pq_ml_dsa_65_sign(uint8_t *sig, size_t *siglen,
+                          const uint8_t *m, size_t mlen,
+                          const uint8_t *sk) {
+    if (sig == NULL || siglen == NULL || m == NULL || sk == NULL) {
+        return -1;
+    }
+    return crypto_sign(sig, siglen, m, mlen, sk);
+}
+
+int fw_pq_ml_dsa_65_verify(const uint8_t *sig, size_t siglen,
+                            const uint8_t *m, size_t mlen,
+                            const uint8_t *pk) {
+    if (sig == NULL || m == NULL || pk == NULL) {
+        return -1;
+    }
+    /* crypto_sign_open expects (m_out, mlen_out, sm, smlen, pk) where sm
+     * is the signed message. For detached signatures we reconstruct: the
+     * PQClean API uses crypto_sign_open with sm = sig || m. */
+    /* For firmware use, we provide a simple verify by re-signing is not
+     * possible (non-deterministic). The PQClean crypto_sign_open expects
+     * the concatenated sig||msg format. Callers should use the PQClean
+     * API directly for verification, or we build the sm buffer here. */
+    uint8_t *sm = (uint8_t *)malloc(siglen + mlen);
+    if (sm == NULL) {
+        return -1;
+    }
+    memcpy(sm, sig, siglen);
+    memcpy(sm + siglen, m, mlen);
+
+    uint8_t *m_out = (uint8_t *)malloc(mlen);
+    if (m_out == NULL) {
+        free(sm);
+        return -1;
+    }
+    size_t mlen_out = 0;
+
+    int ret = crypto_sign_open(m_out, &mlen_out, sm, siglen + mlen, pk);
+
+    free(sm);
+    free(m_out);
+
+    return ret;
+}
+
+int fw_pq_slh_dsa_128s_sign(uint8_t *sig, size_t *siglen,
+                              const uint8_t *m, size_t mlen,
+                              const uint8_t *sk) {
+    if (sig == NULL || siglen == NULL || m == NULL || sk == NULL) {
+        return -1;
+    }
+    /* WARNING: This call takes 5-30 seconds on ESP32. */
+    return slh_dsa_128s_crypto_sign(sig, siglen, m, mlen, sk);
+}
+
+int fw_pq_slh_dsa_128s_verify(const uint8_t *sig, size_t siglen,
+                                const uint8_t *m, size_t mlen,
+                                const uint8_t *pk) {
+    if (sig == NULL || m == NULL || pk == NULL) {
+        return -1;
+    }
+    uint8_t *sm = (uint8_t *)malloc(siglen + mlen);
+    if (sm == NULL) {
+        return -1;
+    }
+    memcpy(sm, sig, siglen);
+    memcpy(sm + siglen, m, mlen);
+
+    uint8_t *m_out = (uint8_t *)malloc(mlen);
+    if (m_out == NULL) {
+        free(sm);
+        return -1;
+    }
+    size_t mlen_out = 0;
+
+    int ret = slh_dsa_128s_crypto_sign_open(m_out, &mlen_out, sm,
+                                             siglen + mlen, pk);
+
+    free(sm);
+    free(m_out);
+
+    return ret;
+}
+
+/* --- KEM --- */
+
+int fw_pq_ml_kem_768_encaps(uint8_t *ct, uint8_t *ss, const uint8_t *pk) {
+    if (ct == NULL || ss == NULL || pk == NULL) {
+        return -1;
+    }
+    /* encaps uses real randomness (hardware RNG) — the DRBG is not
+     * initialized, so randombytes() falls back to esp_fill_random(). */
+    return crypto_kem_enc(ct, ss, pk);
+}
+
+int fw_pq_ml_kem_768_decaps(uint8_t *ss, const uint8_t *ct, const uint8_t *sk) {
+    if (ss == NULL || ct == NULL || sk == NULL) {
+        return -1;
+    }
+    return crypto_kem_dec(ss, ct, sk);
+}

firmware/feather_s3_tft/main/pq_crypto_firmware.h

@@ -0,0 +1,110 @@
+/* pq_crypto_firmware.h — Post-quantum crypto wrappers for ESP32 firmware.
+ *
+ * Provides firmware-friendly wrappers around the PQClean algorithms:
+ *   - ML-DSA-65 (FIPS 204 signatures)
+ *   - SLH-DSA-128s (FIPS 205 hash-based signatures)
+ *   - ML-KEM-768 (FIPS 203 key encapsulation)
+ *
+ * Key generation is deterministic from a 32-byte seed (derived from the
+ * mnemonic via BIP-32/HMAC-SHA512). The seed feeds the deterministic DRBG
+ * (pq_drbg_firmware.c) which replaces PQClean's randombytes() during keygen.
+ *
+ * ed25519 and x25519 are handled separately via mbedtls (see
+ * key_derivation.c) and are not part of this PQClean component.
+ */
+#ifndef FIRMWARE_PQ_CRYPTO_H
+#define FIRMWARE_PQ_CRYPTO_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+/* --- Algorithm identifiers --- */
+typedef enum {
+    FW_PQ_ALG_ML_DSA_65 = 0,
+    FW_PQ_ALG_SLH_DSA_128S,
+    FW_PQ_ALG_ML_KEM_768,
+    FW_PQ_ALG_UNKNOWN
+} fw_pq_alg_t;
+
+/* --- Key sizes (compile-time constants, matching PQClean api.h) --- */
+#define FW_ML_DSA_65_PUBKEY_LEN   1952
+#define FW_ML_DSA_65_PRIVKEY_LEN  4032
+#define FW_ML_DSA_65_SIG_LEN      3309
+
+#define FW_SLH_DSA_128S_PUBKEY_LEN   32
+#define FW_SLH_DSA_128S_PRIVKEY_LEN  64
+#define FW_SLH_DSA_128S_SIG_LEN      7856
+
+#define FW_ML_KEM_768_PUBKEY_LEN      1184
+#define FW_ML_KEM_768_PRIVKEY_LEN     2400
+#define FW_ML_KEM_768_CIPHERTEXT_LEN  1088
+#define FW_ML_KEM_768_SHARED_SECRET_LEN 32
+
+/* --- Key generation (deterministic from seed) --- */
+
+/* Generate an ML-DSA-65 keypair from a 32-byte seed.
+ * pk must be at least FW_ML_DSA_65_PUBKEY_LEN bytes.
+ * sk must be at least FW_ML_DSA_65_PRIVKEY_LEN bytes.
+ * Returns 0 on success, -1 on error. */
+int fw_pq_ml_dsa_65_keygen(const uint8_t seed[32],
+                            uint8_t *pk, uint8_t *sk);
+
+/* Generate an SLH-DSA-128s keypair from a 32-byte seed.
+ * pk must be at least FW_SLH_DSA_128S_PUBKEY_LEN bytes.
+ * sk must be at least FW_SLH_DSA_128S_PRIVKEY_LEN bytes.
+ * Returns 0 on success, -1 on error.
+ * WARNING: SLH-DSA-128s keygen takes 5-30 seconds on ESP32. */
+int fw_pq_slh_dsa_128s_keygen(const uint8_t seed[32],
+                               uint8_t *pk, uint8_t *sk);
+
+/* Generate an ML-KEM-768 keypair from a 32-byte seed.
+ * pk must be at least FW_ML_KEM_768_PUBKEY_LEN bytes.
+ * sk must be at least FW_ML_KEM_768_PRIVKEY_LEN bytes.
+ * Returns 0 on success, -1 on error. */
+int fw_pq_ml_kem_768_keygen(const uint8_t seed[32],
+                             uint8_t *pk, uint8_t *sk);
+
+/* --- Signing (ML-DSA-65, SLH-DSA-128s) --- */
+
+/* Sign a message with ML-DSA-65.
+ * sig must be at least FW_ML_DSA_65_SIG_LEN bytes.
+ * Returns 0 on success, -1 on error. */
+int fw_pq_ml_dsa_65_sign(uint8_t *sig, size_t *siglen,
+                          const uint8_t *m, size_t mlen,
+                          const uint8_t *sk);
+
+/* Verify an ML-DSA-65 signature.
+ * Returns 0 on valid, -1 on invalid. */
+int fw_pq_ml_dsa_65_verify(const uint8_t *sig, size_t siglen,
+                            const uint8_t *m, size_t mlen,
+                            const uint8_t *pk);
+
+/* Sign a message with SLH-DSA-128s.
+ * sig must be at least FW_SLH_DSA_128S_SIG_LEN bytes.
+ * WARNING: SLH-DSA-128s signing takes 5-30 seconds on ESP32.
+ * Returns 0 on success, -1 on error. */
+int fw_pq_slh_dsa_128s_sign(uint8_t *sig, size_t *siglen,
+                              const uint8_t *m, size_t mlen,
+                              const uint8_t *sk);
+
+/* Verify an SLH-DSA-128s signature.
+ * Returns 0 on valid, -1 on invalid. */
+int fw_pq_slh_dsa_128s_verify(const uint8_t *sig, size_t siglen,
+                                const uint8_t *m, size_t mlen,
+                                const uint8_t *pk);
+
+/* --- KEM (ML-KEM-768) --- */
+
+/* Encapsulate: generate ciphertext + shared secret from a public key.
+ * Uses real randomness (ESP32 hardware RNG) — not the deterministic DRBG.
+ * ct must be at least FW_ML_KEM_768_CIPHERTEXT_LEN bytes.
+ * ss must be at least FW_ML_KEM_768_SHARED_SECRET_LEN bytes.
+ * Returns 0 on success, -1 on error. */
+int fw_pq_ml_kem_768_encaps(uint8_t *ct, uint8_t *ss, const uint8_t *pk);
+
+/* Decapsulate: recover shared secret from secret key + ciphertext.
+ * ss must be at least FW_ML_KEM_768_SHARED_SECRET_LEN bytes.
+ * Returns 0 on success, -1 on error. */
+int fw_pq_ml_kem_768_decaps(uint8_t *ss, const uint8_t *ct, const uint8_t *sk);
+
+#endif /* FIRMWARE_PQ_CRYPTO_H */

increment_and_push.sh

@@ -181,10 +181,12 @@ build_release_binary() {
     # Prevent stale artifacts from previous builds being uploaded.
     rm -f build/nsigner_static_x86_64 build/nsigner_static_arm64
 
-    ./build_static.sh > /dev/null 2>&1 || return 1
+    print_status "Building x86_64 static binary (this may take a few minutes with PQ algorithms)..."
+    ./build_static.sh 2>&1 | tail -5 || return 1
     verify_binary_version "build/nsigner_static_x86_64" "$NEW_VERSION" || return 1
 
-    ./build_static.sh --arch arm64 > /dev/null 2>&1 || print_warning "ARM64 build failed (continuing)"
+    print_status "Building ARM64 static binary..."
+    ./build_static.sh --arch arm64 2>&1 | tail -5 || print_warning "ARM64 build failed (continuing)"
     if [[ -x "build/nsigner_static_arm64" ]]; then
         verify_binary_version "build/nsigner_static_arm64" "$NEW_VERSION" || return 1
     fi
@@ -221,11 +223,25 @@ create_gitea_release() {
     response=$(curl -s -X POST "$api_url/releases" \
         -H "Authorization: token $token" \
         -H "Content-Type: application/json" \
-        -d "{\"tag_name\": \"$NEW_VERSION\", \"name\": \"$NEW_VERSION\", \"body\": \"$COMMIT_MESSAGE\"}")
+        -d "{\"tag_name\": \"$NEW_VERSION\", \"target_commitish\": \"master\", \"name\": \"$NEW_VERSION\", \"body\": \"$COMMIT_MESSAGE\", \"draft\": false, \"prerelease\": false}")
 
     if echo "$response" | grep -q '"id"'; then
-        echo "$response" | grep -o '"id":[0-9]*' | head -1 | cut -d':' -f2
+        local release_id
+        release_id=$(echo "$response" | grep -o '"id":[0-9]*' | head -1 | cut -d':' -f2)
+
+        # Work around Gitea bug: releases created via API get created_unix=0
+        # (epoch zero) in the database, causing them to not appear in the
+        # releases list or web UI. Fix the timestamp directly in the DB.
+        local now_unix
+        now_unix=$(date +%s)
+        print_status "Fixing release timestamp in Gitea database (workaround for Gitea bug)..."
+        ssh -o ConnectTimeout=10 ubuntu@laantungir.net \
+            "sudo sqlite3 /data/gitea/gitea.db \"UPDATE release SET created_unix=$now_unix WHERE id=$release_id;\"" \
+            2>/dev/null || print_warning "Could not fix release timestamp via SSH (release may not appear in web UI)"
+
+        echo "$release_id"
     else
+        print_error "Failed to create Gitea release: $response"
         return 1
     fi
 }

install_qube_fips_nsigner.sh

@@ -84,12 +84,21 @@ resolve_nsigner_version() {
     headers=(-H "Authorization: token ${NSIGNER_GITEA_TOKEN}")
   fi
 
+  # Use the git tags API and sort by version number, instead of the releases
+  # API which sorts by created_at timestamp. Gitea has a bug where some
+  # releases get epoch-zero timestamps and don't appear in the releases list.
+  latest_tag="$(curl -fsSL "${headers[@]}" "https://git.laantungir.net/api/v1/repos/laantungir/n_signer/tags?limit=50" \
+    | jq -r '[.[].name] | map(select(startswith("v"))) | sort_by(ltrimstr("v") | split(".") | map(tonumber)) | last // empty' || true)"
+
+  if [[ -z "${latest_tag}" ]]; then
+    # Fallback: try the releases API (old behavior)
     latest_tag="$(curl -fsSL "${headers[@]}" "https://git.laantungir.net/api/v1/repos/laantungir/n_signer/releases" \
       | jq -r '.[0].tag_name // empty' || true)"
+  fi
 
   if [[ -z "${latest_tag}" ]]; then
     err "Could not resolve latest n_signer release tag from API."
-    err "Set NSIGNER_VERSION explicitly (e.g. NSIGNER_VERSION=v0.0.11)."
+    err "Set NSIGNER_VERSION explicitly (e.g. NSIGNER_VERSION=v0.0.46)."
     exit 1
   fi
 
@@ -176,7 +185,7 @@ write_signer_start_script() {
 set -euo pipefail
 
 export PATH="$HOME/.local/bin:$PATH"
-LISTEN_TARGET="${NSIGNER_LISTEN_TARGET:-tcp:[::]:8080}"
+LISTEN_TARGET="${NSIGNER_LISTEN_TARGET:-tcp:[::]:11111}"
 
 # If first arg is "qrexec", start in unix bridge mode for Qubes qrexec.
 # Otherwise, pass any extra args through to nsigner (e.g. --allow-all).

libotppad/Makefile

@@ -0,0 +1,25 @@
+CC ?= gcc
+CFLAGS ?= -Wall -Wextra -std=c99 -O2
+AR ?= ar
+
+OBJS = libotppad.o
+LIB  = libotppad.a
+
+all: $(LIB)
+
+$(LIB): $(OBJS)
+	$(AR) rcs $@ $(OBJS)
+
+libotppad.o: libotppad.c libotppad.h
+	$(CC) $(CFLAGS) -c libotppad.c -o libotppad.o
+
+test: test_libotppad
+	./test_libotppad
+
+test_libotppad: test_libotppad.c $(LIB)
+	$(CC) $(CFLAGS) -I. test_libotppad.c -L. -lotppad -o test_libotppad
+
+clean:
+	rm -f $(OBJS) $(LIB) test_libotppad
+
+.PHONY: all test clean

libotppad/libotppad.c

@@ -0,0 +1,398 @@
+/*
+ * libotppad.c — implementation of libotppad.h.
+ *
+ * Extracted from the otp project (src/crypto.c, src/padding.c, src/pads.c)
+ * and made self-contained: no main.h, no global state, no UI.
+ */
+#define _POSIX_C_SOURCE 200809L
+
+#include "libotppad.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <unistd.h>
+
+/* ------------------------------------------------------------------ */
+/* XOR transform                                                      */
+/* ------------------------------------------------------------------ */
+
+int otppad_xor(const unsigned char *data, size_t data_len,
+               const unsigned char *pad_data, unsigned char *result) {
+    if (!data || !pad_data || !result) {
+        return 1;
+    }
+    for (size_t i = 0; i < data_len; i++) {
+        result[i] = data[i] ^ pad_data[i];
+    }
+    return 0;
+}
+
+/* ------------------------------------------------------------------ */
+/* Base64                                                             */
+/* ------------------------------------------------------------------ */
+
+static const char b64_chars[] =
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+static const int b64_decode_table[256] = {
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,62,-1,-1,-1,63,
+    52,53,54,55,56,57,58,59,60,61,-1,-1,-1,-2,-1,-1,
+    -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,
+    15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1,
+    -1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,
+    41,42,43,44,45,46,47,48,49,50,51,-1,-1,-1,-1,-1,
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1
+};
+
+char *otppad_base64_encode(const unsigned char *input, int length) {
+    if (!input || length < 0) return NULL;
+    int output_length = 4 * ((length + 2) / 3);
+    char *encoded = (char *)malloc((size_t)output_length + 1);
+    if (!encoded) return NULL;
+
+    int i, j;
+    for (i = 0, j = 0; i < length;) {
+        uint32_t octet_a = i < length ? input[i++] : 0;
+        uint32_t octet_b = i < length ? input[i++] : 0;
+        uint32_t octet_c = i < length ? input[i++] : 0;
+        uint32_t triple = (octet_a << 16) + (octet_b << 8) + octet_c;
+        encoded[j++] = b64_chars[(triple >> 18) & 63];
+        encoded[j++] = b64_chars[(triple >> 12) & 63];
+        encoded[j++] = b64_chars[(triple >> 6) & 63];
+        encoded[j++] = b64_chars[triple & 63];
+    }
+    for (int pad = 0; pad < (3 - length % 3) % 3; pad++) {
+        encoded[output_length - 1 - pad] = '=';
+    }
+    encoded[output_length] = '\0';
+    return encoded;
+}
+
+unsigned char *otppad_base64_decode(const char *input, int *output_length) {
+    if (!input || !output_length) return NULL;
+    int input_length = (int)strlen(input);
+    if (input_length % 4 != 0) return NULL;
+
+    *output_length = input_length / 4 * 3;
+    if (input[input_length - 1] == '=') (*output_length)--;
+    if (input[input_length - 2] == '=') (*output_length)--;
+
+    unsigned char *decoded = (unsigned char *)malloc((size_t)*output_length);
+    if (!decoded) return NULL;
+
+    int i, j;
+    for (i = 0, j = 0; i < input_length;) {
+        int sa = input[i] == '=' ? 0 & i++ : b64_decode_table[(unsigned char)input[i++]];
+        int sb = input[i] == '=' ? 0 & i++ : b64_decode_table[(unsigned char)input[i++]];
+        int sc = input[i] == '=' ? 0 & i++ : b64_decode_table[(unsigned char)input[i++]];
+        int sd = input[i] == '=' ? 0 & i++ : b64_decode_table[(unsigned char)input[i++]];
+        if (sa == -1 || sb == -1 || sc == -1 || sd == -1) {
+            free(decoded);
+            return NULL;
+        }
+        uint32_t triple = ((uint32_t)sa << 18) + ((uint32_t)sb << 12) +
+                          ((uint32_t)sc << 6) + (uint32_t)sd;
+        if (j < *output_length) decoded[j++] = (triple >> 16) & 255;
+        if (j < *output_length) decoded[j++] = (triple >> 8) & 255;
+        if (j < *output_length) decoded[j++] = triple & 255;
+    }
+    return decoded;
+}
+
+/* ------------------------------------------------------------------ */
+/* Padmé padding                                                      */
+/* ------------------------------------------------------------------ */
+
+size_t otppad_chunk_size(size_t msg_len) {
+    size_t chunk = 256;
+    while (chunk < msg_len + 1) {
+        chunk *= 2;
+    }
+    return chunk;
+}
+
+int otppad_pad_apply(unsigned char *buffer, size_t msg_len, size_t chunk_size) {
+    if (!buffer) return 1;
+    if (chunk_size < msg_len + 1) return 2;
+    buffer[msg_len] = 0x80;
+    if (chunk_size > msg_len + 1) {
+        memset(buffer + msg_len + 1, 0x00, chunk_size - msg_len - 1);
+    }
+    return 0;
+}
+
+int otppad_pad_remove(const unsigned char *buffer, size_t chunk_size,
+                      size_t *msg_len) {
+    if (!buffer || !msg_len) return 1;
+    if (chunk_size == 0) return 2;
+    for (int i = (int)chunk_size - 1; i >= 0; i--) {
+        if (buffer[i] == 0x80) {
+            *msg_len = (size_t)i;
+            return 0;
+        } else if (buffer[i] != 0x00) {
+            return 3;
+        }
+    }
+    return 4;
+}
+
+void otppad_chunk_format(size_t chunk_size, char *buffer, size_t buffer_size) {
+    if (!buffer || buffer_size == 0) return;
+    if (chunk_size < 1024) {
+        snprintf(buffer, buffer_size, "%zu bytes", chunk_size);
+    } else if (chunk_size < 1024 * 1024) {
+        snprintf(buffer, buffer_size, "%.1f KB", chunk_size / 1024.0);
+    } else if (chunk_size < 1024 * 1024 * 1024) {
+        snprintf(buffer, buffer_size, "%.1f MB", chunk_size / (1024.0 * 1024.0));
+    } else {
+        snprintf(buffer, buffer_size, "%.1f GB",
+                 chunk_size / (1024.0 * 1024.0 * 1024.0));
+    }
+}
+
+/* ------------------------------------------------------------------ */
+/* ASCII armored message format                                       */
+/* ------------------------------------------------------------------ */
+
+int otppad_armor_parse(const char *message, char *chksum, uint64_t *offset,
+                       char *base64_data, size_t base64_buf_size) {
+    if (!message || !chksum || !offset || !base64_data || base64_buf_size == 0) {
+        return 1;
+    }
+
+    size_t msg_len = strlen(message);
+    char *copy = (char *)malloc(msg_len + 1);
+    if (!copy) return 1;
+    strcpy(copy, message);
+
+    char *line = strtok(copy, "\n");
+    int found_begin = 0, in_data = 0, found_chksum = 0, found_offset = 0;
+    chksum[0] = '\0';
+    *offset = 0;
+    base64_data[0] = '\0';
+
+    while (line != NULL) {
+        if (strcmp(line, OTPPAD_ARMOR_BEGIN) == 0) {
+            found_begin = 1;
+        } else if (strcmp(line, OTPPAD_ARMOR_END) == 0) {
+            break;
+        } else if (found_begin) {
+            if (strncmp(line, "Pad-ChkSum: ", 12) == 0) {
+                strncpy(chksum, line + 12, OTPPAD_CHKSUM_HEX_LEN);
+                chksum[OTPPAD_CHKSUM_HEX_LEN] = '\0';
+                found_chksum = 1;
+            } else if (strncmp(line, "Pad-Offset: ", 12) == 0) {
+                *offset = strtoull(line + 12, NULL, 10);
+                found_offset = 1;
+            } else if (strlen(line) == 0) {
+                in_data = 1;
+            } else if (in_data) {
+                strncat(base64_data, line, base64_buf_size - strlen(base64_data) - 1);
+            } else if (strncmp(line, "Version:", 8) != 0 &&
+                       strncmp(line, "Pad-", 4) != 0) {
+                strncat(base64_data, line, base64_buf_size - strlen(base64_data) - 1);
+            }
+        }
+        line = strtok(NULL, "\n");
+    }
+
+    free(copy);
+    if (!found_begin || !found_chksum || !found_offset) {
+        return 2;
+    }
+    return 0;
+}
+
+int otppad_armor_generate(const char *version, const char *chksum,
+                          uint64_t offset,
+                          const unsigned char *encrypted_data, size_t data_length,
+                          char **ascii_output) {
+    if (!chksum || !encrypted_data || !ascii_output) return 1;
+
+    char *b64 = otppad_base64_encode(encrypted_data, (int)data_length);
+    if (!b64) return 2;
+
+    size_t b64_len = strlen(b64);
+    size_t total = 256 + b64_len + (b64_len / 64) + 64;
+    *ascii_output = (char *)malloc(total);
+    if (!*ascii_output) {
+        free(b64);
+        return 3;
+    }
+
+    char line[256];
+    strcpy(*ascii_output, OTPPAD_ARMOR_BEGIN);
+    strcat(*ascii_output, "\n");
+
+    snprintf(line, sizeof(line), "Version: %s\n", version ? version : "v0");
+    strcat(*ascii_output, line);
+
+    snprintf(line, sizeof(line), "Pad-ChkSum: %s\n", chksum);
+    strcat(*ascii_output, line);
+
+    snprintf(line, sizeof(line), "Pad-Offset: %llu\n",
+             (unsigned long long)offset);
+    strcat(*ascii_output, line);
+
+    strcat(*ascii_output, "\n");
+
+    int b64_len_int = (int)b64_len;
+    for (int i = 0; i < b64_len_int; i += 64) {
+        snprintf(line, sizeof(line), "%.64s\n", b64 + i);
+        strcat(*ascii_output, line);
+    }
+
+    strcat(*ascii_output, OTPPAD_ARMOR_END);
+    strcat(*ascii_output, "\n");
+
+    free(b64);
+    return 0;
+}
+
+/* ------------------------------------------------------------------ */
+/* Binary .otp file format                                            */
+/* ------------------------------------------------------------------ */
+
+int otppad_bin_header_write(FILE *fp, const otppad_bin_header_t *hdr) {
+    if (!fp || !hdr) return 1;
+    if (fwrite(OTPPAD_MAGIC, 1, OTPPAD_MAGIC_LEN, fp) != OTPPAD_MAGIC_LEN) return 2;
+    if (fwrite(&hdr->version, sizeof(uint16_t), 1, fp) != 1) return 3;
+    if (fwrite(hdr->pad_chksum, 1, OTPPAD_CHKSUM_BIN_LEN, fp) != OTPPAD_CHKSUM_BIN_LEN) return 4;
+    if (fwrite(&hdr->pad_offset, sizeof(uint64_t), 1, fp) != 1) return 5;
+    if (fwrite(&hdr->file_mode, sizeof(uint32_t), 1, fp) != 1) return 6;
+    if (fwrite(&hdr->file_size, sizeof(uint64_t), 1, fp) != 1) return 7;
+    return 0;
+}
+
+int otppad_bin_header_read(FILE *fp, otppad_bin_header_t *hdr) {
+    if (!fp || !hdr) return 1;
+    memset(hdr, 0, sizeof(*hdr));
+    if (fread(hdr->magic, 1, OTPPAD_MAGIC_LEN, fp) != OTPPAD_MAGIC_LEN) return 2;
+    if (fread(&hdr->version, sizeof(uint16_t), 1, fp) != 1) return 3;
+    if (fread(hdr->pad_chksum, 1, OTPPAD_CHKSUM_BIN_LEN, fp) != OTPPAD_CHKSUM_BIN_LEN) return 4;
+    if (fread(&hdr->pad_offset, sizeof(uint64_t), 1, fp) != 1) return 5;
+    if (fread(&hdr->file_mode, sizeof(uint32_t), 1, fp) != 1) return 6;
+    if (fread(&hdr->file_size, sizeof(uint64_t), 1, fp) != 1) return 7;
+    return 0;
+}
+
+int otppad_bin_is_magic(const unsigned char *buf, size_t len) {
+    if (!buf || len < OTPPAD_MAGIC_LEN) return 0;
+    return memcmp(buf, OTPPAD_MAGIC, OTPPAD_MAGIC_LEN) == 0;
+}
+
+/* ------------------------------------------------------------------ */
+/* Per-pad .state file                                                */
+/* ------------------------------------------------------------------ */
+
+int otppad_state_read(const char *pads_dir, const char *chksum, uint64_t *offset) {
+    if (!pads_dir || !chksum || !offset) return 1;
+    char path[1024];
+    snprintf(path, sizeof(path), "%s/%s.state", pads_dir, chksum);
+
+    FILE *f = fopen(path, "r");
+    if (!f) return 2;
+
+    char line[128];
+    if (!fgets(line, sizeof(line), f)) {
+        fclose(f);
+        return 3;
+    }
+    fclose(f);
+
+    if (strncmp(line, "offset=", 7) != 0) {
+        return 4;
+    }
+    *offset = strtoull(line + 7, NULL, 10);
+    return 0;
+}
+
+int otppad_state_write(const char *pads_dir, const char *chksum, uint64_t offset) {
+    if (!pads_dir || !chksum) return 1;
+    char path[1024];
+    char tmp[1100];
+    snprintf(path, sizeof(path), "%s/%s.state", pads_dir, chksum);
+    snprintf(tmp, sizeof(tmp), "%s/%s.state.tmp.XXXXXX", pads_dir, chksum);
+
+    int tfd = mkstemp(tmp);
+    if (tfd < 0) return 2;
+    FILE *f = fdopen(tfd, "w");
+    if (!f) {
+        close(tfd);
+        unlink(tmp);
+        return 3;
+    }
+    if (fprintf(f, "offset=%llu\n", (unsigned long long)offset) < 0) {
+        fclose(f);
+        unlink(tmp);
+        return 4;
+    }
+    if (fclose(f) != 0) {
+        unlink(tmp);
+        return 5;
+    }
+    if (rename(tmp, path) != 0) {
+        unlink(tmp);
+        return 6;
+    }
+    return 0;
+}
+
+/* ------------------------------------------------------------------ */
+/* Pad checksum                                                       */
+/* ------------------------------------------------------------------ */
+
+int otppad_checksum(const char *pad_path, char *checksum_hex) {
+    if (!pad_path || !checksum_hex) return 1;
+
+    FILE *file = fopen(pad_path, "rb");
+    if (!file) return 2;
+
+    unsigned char checksum[OTPPAD_CHKSUM_BIN_LEN];
+    unsigned char buffer[64 * 1024];
+    size_t bytes_read;
+    size_t total_bytes = 0;
+    memset(checksum, 0, OTPPAD_CHKSUM_BIN_LEN);
+
+    while ((bytes_read = fread(buffer, 1, sizeof(buffer), file)) > 0) {
+        for (size_t i = 0; i < bytes_read; i++) {
+            size_t pos = total_bytes + i;
+            unsigned char bucket = (unsigned char)(pos % OTPPAD_CHKSUM_BIN_LEN);
+            checksum[bucket] ^= (unsigned char)buffer[i] ^
+                                (unsigned char)((pos >> 8) & 0xFF) ^
+                                (unsigned char)((pos >> 16) & 0xFF) ^
+                                (unsigned char)((pos >> 24) & 0xFF);
+        }
+        total_bytes += bytes_read;
+    }
+    fclose(file);
+
+    file = fopen(pad_path, "rb");
+    if (!file) return 3;
+    unsigned char pad_key[OTPPAD_CHKSUM_BIN_LEN];
+    if (fread(pad_key, 1, OTPPAD_CHKSUM_BIN_LEN, file) != OTPPAD_CHKSUM_BIN_LEN) {
+        fclose(file);
+        return 4;
+    }
+    fclose(file);
+
+    unsigned char enc[OTPPAD_CHKSUM_BIN_LEN];
+    for (int i = 0; i < OTPPAD_CHKSUM_BIN_LEN; i++) {
+        enc[i] = checksum[i] ^ pad_key[i];
+    }
+    for (int i = 0; i < OTPPAD_CHKSUM_BIN_LEN; i++) {
+        sprintf(checksum_hex + (i * 2), "%02x", enc[i]);
+    }
+    checksum_hex[OTPPAD_CHKSUM_HEX_LEN] = '\0';
+    return 0;
+}

libotppad/libotppad.h

@@ -0,0 +1,201 @@
+/*
+ * libotppad.h — format-critical helpers for one-time-pad encryption.
+ *
+ * Bit-compatible with the `otp` project (https://git.laantungir.net/laantungir/otp):
+ *   - XOR transform
+ *   - ASCII armored message format ("-----BEGIN OTP MESSAGE-----")
+ *   - Binary .otp file format (magic "OTP\0")
+ *   - ISO/IEC 9797-1 Method 2 (Padmé) padding with exponential bucketing
+ *   - Per-pad .state file ("offset=<n>\n")
+ *   - 256-bit XOR pad checksum (position-dependent, XORed with first 32 pad bytes)
+ *
+ * This library is self-contained: it does not depend on the `otp` project's
+ * main.h, global state, or UI code. Both `otp` and `n_signer` link against it.
+ *
+ * License: same as the otp project.
+ */
+#ifndef LIBOTPPAD_H
+#define LIBOTPPAD_H
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* ------------------------------------------------------------------ */
+/* Constants                                                          */
+/* ------------------------------------------------------------------ */
+
+#define OTPPAD_CHKSUM_HEX_LEN   64          /* 32 bytes -> 64 hex chars */
+#define OTPPAD_CHKSUM_BIN_LEN   32
+#define OTPPAD_HEADER_RESERVED  32          /* bytes reserved at start of pad */
+#define OTPPAD_MAGIC            "OTP\0"     /* 4-byte binary file magic   */
+#define OTPPAD_MAGIC_LEN        4
+#define OTPPAD_FORMAT_VERSION   1           /* binary .otp format version */
+
+#define OTPPAD_ARMOR_BEGIN      "-----BEGIN OTP MESSAGE-----"
+#define OTPPAD_ARMOR_END        "-----END OTP MESSAGE-----"
+
+/* ------------------------------------------------------------------ */
+/* XOR transform                                                      */
+/* ------------------------------------------------------------------ */
+
+/*
+ * XOR `data_len` bytes of `data` with `pad_data` into `result`.
+ * `data`, `pad_data`, `result` must each be at least `data_len` bytes.
+ * `result` may alias `data` or `pad_data`.
+ * Returns 0 on success, non-zero on null pointer.
+ */
+int otppad_xor(const unsigned char *data, size_t data_len,
+               const unsigned char *pad_data, unsigned char *result);
+
+/* ------------------------------------------------------------------ */
+/* Base64                                                             */
+/* ------------------------------------------------------------------ */
+
+/* Encode `length` bytes of `input` as a NUL-terminated base64 string.
+ * Caller frees the returned string. Returns NULL on allocation failure. */
+char *otppad_base64_encode(const unsigned char *input, int length);
+
+/* Decode NUL-terminated base64 `input` into bytes.
+ * Caller frees the returned buffer. *output_length receives the byte count.
+ * Returns NULL on invalid input or allocation failure. */
+unsigned char *otppad_base64_decode(const char *input, int *output_length);
+
+/* ------------------------------------------------------------------ */
+/* Padmé padding (ISO/IEC 9797-1 Method 2) + exponential bucketing    */
+/* ------------------------------------------------------------------ */
+
+/* Calculate the bucket size for a message of `msg_len` bytes.
+ * Starts at 256 bytes and doubles until `chunk >= msg_len + 1`. */
+size_t otppad_chunk_size(size_t msg_len);
+
+/* Apply Padmé padding to `buffer` (must hold `chunk_size` bytes).
+ * Writes 0x80 at `buffer[msg_len]` then zeroes to `chunk_size`.
+ * Returns 0 on success, non-zero on error. */
+int otppad_pad_apply(unsigned char *buffer, size_t msg_len, size_t chunk_size);
+
+/* Remove Padmé padding: scan backwards for 0x80, set *msg_len to its index.
+ * Returns 0 on success, non-zero on invalid padding. */
+int otppad_pad_remove(const unsigned char *buffer, size_t chunk_size,
+                      size_t *msg_len);
+
+/* Human-readable chunk size string (e.g. "256 bytes", "1.0 KB"). */
+void otppad_chunk_format(size_t chunk_size, char *buffer, size_t buffer_size);
+
+/* ------------------------------------------------------------------ */
+/* ASCII armored message format                                       */
+/* ------------------------------------------------------------------ */
+
+/*
+ * Parse an ASCII-armored OTP message.
+ *
+ * `chksum` must be at least OTPPAD_CHKSUM_HEX_LEN+1 bytes.
+ * `base64_data` must be at least `base64_buf_size` bytes; the decoded
+ * ciphertext is NOT returned here — only the raw base64 text. Use
+ * otppad_base64_decode() to get the bytes.
+ *
+ * On success returns 0 and sets `chksum`, `*offset`, and `base64_data`.
+ * Returns non-zero on malformed input.
+ */
+int otppad_armor_parse(const char *message, char *chksum, uint64_t *offset,
+                       char *base64_data, size_t base64_buf_size);
+
+/*
+ * Build an ASCII-armored OTP message.
+ *
+ * `version` is the version string for the "Version:" header (e.g. "v0.3.53").
+ * `chksum` is the 64-char hex pad checksum.
+ * `offset` is the pad offset where the slice begins.
+ * `encrypted_data` / `data_length` is the ciphertext to base64-encode.
+ *
+ * On success returns 0 and sets `*ascii_output` to a malloc'd NUL-terminated
+ * string. Caller frees `*ascii_output`.
+ */
+int otppad_armor_generate(const char *version, const char *chksum,
+                          uint64_t offset,
+                          const unsigned char *encrypted_data, size_t data_length,
+                          char **ascii_output);
+
+/* ------------------------------------------------------------------ */
+/* Binary .otp file format                                            */
+/* ------------------------------------------------------------------ */
+
+/*
+ * Binary .otp header (58 bytes). All fields are little-endian on disk
+ * (written via fwrite of host-endian integers — matches the otp project,
+ * which is x86/ARM little-endian in practice).
+ *
+ * Offset  Size  Field
+ * 0       4     Magic "OTP\0"
+ * 4       2     Version (uint16, currently 1)
+ * 6       32    Pad checksum (binary, 32 bytes)
+ * 38      8     Pad offset (uint64)
+ * 46      4     Original file mode (uint32)
+ * 50      8     Original file size (uint64, NOT padded size)
+ * 58      var   Encrypted (padded) data
+ */
+typedef struct {
+    char          magic[OTPPAD_MAGIC_LEN];
+    uint16_t      version;
+    unsigned char pad_chksum[OTPPAD_CHKSUM_BIN_LEN];
+    uint64_t      pad_offset;
+    uint32_t      file_mode;
+    uint64_t      file_size;        /* original (unpadded) size */
+} otppad_bin_header_t;
+
+/* Write a binary .otp header to `fp`. Returns 0 on success. */
+int otppad_bin_header_write(FILE *fp, const otppad_bin_header_t *hdr);
+
+/* Read a binary .otp header from `fp`. Returns 0 on success, non-zero on
+ * malformed input. Does not validate the magic — use otppad_bin_is_magic()
+ * first if needed. */
+int otppad_bin_header_read(FILE *fp, otppad_bin_header_t *hdr);
+
+/* Return 1 if the first 4 bytes of `buf` match the OTP magic. */
+int otppad_bin_is_magic(const unsigned char *buf, size_t len);
+
+/* ------------------------------------------------------------------ */
+/* Per-pad .state file                                                */
+/* ------------------------------------------------------------------ */
+
+/*
+ * Read the offset from `<pads_dir>/<chksum>.state`.
+ * Returns 0 on success and sets *offset. Non-zero on error.
+ */
+int otppad_state_read(const char *pads_dir, const char *chksum, uint64_t *offset);
+
+/*
+ * Atomically write the offset to `<pads_dir>/<chksum>.state`.
+ * Writes to a temp file then renames, so a crash cannot corrupt the state.
+ * Returns 0 on success, non-zero on error.
+ */
+int otppad_state_write(const char *pads_dir, const char *chksum, uint64_t offset);
+
+/* ------------------------------------------------------------------ */
+/* Pad checksum                                                       */
+/* ------------------------------------------------------------------ */
+
+/*
+ * Compute the 256-bit XOR checksum of the pad file at `pad_path`.
+ * `checksum_hex` must be at least OTPPAD_CHKSUM_HEX_LEN+1 bytes.
+ *
+ * Algorithm (matches otp/src/crypto.c:calculate_checksum):
+ *   - XOR every byte into one of 32 buckets, selected by (position % 32),
+ *     also XORing in bytes (pos>>8),(pos>>16),(pos>>24) of the position.
+ *   - XOR the resulting 32-byte checksum with the first 32 bytes of the pad
+ *     (the "pad key").
+ *   - Hex-encode the 32-byte result.
+ *
+ * Returns 0 on success, non-zero on error.
+ */
+int otppad_checksum(const char *pad_path, char *checksum_hex);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LIBOTPPAD_H */

libotppad/test_libotppad.c

@@ -0,0 +1,213 @@
+/*
+ * test_libotppad.c — unit tests for libotppad.
+ *
+ * Covers: XOR, base64 round-trip, Padmé padding round-trip, ASCII armor
+ * round-trip, binary header round-trip, .state file round-trip, and pad
+ * checksum against a known pad.
+ */
+#define _POSIX_C_SOURCE 200809L
+
+#include "libotppad.h"
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+static int failures = 0;
+
+#define CHECK(cond, msg) do { \
+    if (!(cond)) { \
+        fprintf(stderr, "FAIL: %s (%s:%d)\n", (msg), __FILE__, __LINE__); \
+        failures++; \
+    } else { \
+        printf("ok: %s\n", (msg)); \
+    } \
+} while (0)
+
+static void test_xor(void) {
+    unsigned char data[] = {0x01, 0x02, 0x03, 0x04, 0x05};
+    unsigned char pad[]  = {0xff, 0xee, 0xdd, 0xcc, 0xbb};
+    unsigned char out[5];
+    CHECK(otppad_xor(data, 5, pad, out) == 0, "xor returns 0");
+    CHECK(out[0] == 0xfe && out[1] == 0xec && out[2] == 0xde &&
+          out[3] == 0xc8 && out[4] == 0xbe, "xor values correct");
+    /* in-place aliasing */
+    CHECK(otppad_xor(data, 5, pad, data) == 0, "xor in-place");
+    CHECK(data[0] == 0xfe, "xor in-place value");
+}
+
+static void test_base64(void) {
+    const char *in = "Hello, World!";
+    int len = (int)strlen(in);
+    char *enc = otppad_base64_encode((const unsigned char *)in, len);
+    CHECK(enc != NULL, "base64 encode");
+    int dlen = 0;
+    unsigned char *dec = otppad_base64_decode(enc, &dlen);
+    CHECK(dec != NULL, "base64 decode");
+    CHECK(dlen == len, "base64 length preserved");
+    CHECK(memcmp(dec, in, len) == 0, "base64 round-trip");
+    free(enc);
+    free(dec);
+
+    /* empty input */
+    enc = otppad_base64_encode((const unsigned char *)"", 0);
+    CHECK(enc != NULL && strcmp(enc, "") == 0, "base64 empty");
+    free(enc);
+}
+
+static void test_padding(void) {
+    /* 10-byte message -> 256-byte bucket */
+    size_t chunk = otppad_chunk_size(10);
+    CHECK(chunk == 256, "chunk size for 10 bytes is 256");
+    /* 300-byte message -> 512-byte bucket */
+    chunk = otppad_chunk_size(300);
+    CHECK(chunk == 512, "chunk size for 300 bytes is 512");
+    /* 256-byte message -> 512 (needs +1 for 0x80) */
+    chunk = otppad_chunk_size(256);
+    CHECK(chunk == 512, "chunk size for 256 bytes is 512 (needs +1)");
+
+    unsigned char buf[512];
+    const char *msg = "test message";
+    size_t msg_len = strlen(msg);
+    memset(buf, 0xaa, sizeof(buf));
+    memcpy(buf, msg, msg_len);
+    chunk = otppad_chunk_size(msg_len);
+    CHECK(otppad_pad_apply(buf, msg_len, chunk) == 0, "pad apply");
+    CHECK(buf[msg_len] == 0x80, "pad marker at msg_len");
+    size_t recovered;
+    CHECK(otppad_pad_remove(buf, chunk, &recovered) == 0, "pad remove");
+    CHECK(recovered == msg_len, "pad remove recovers length");
+    CHECK(memcmp(buf, msg, msg_len) == 0, "pad round-trip preserves message");
+}
+
+static void test_armor(void) {
+    const char *chksum =
+        "333e9902db839d9d7f1f6aaa30f392a77c9abd011dd6274d9d3cf167361a789e";
+    unsigned char ct[] = {0xde, 0xad, 0xbe, 0xef, 0x10, 0x20, 0x30, 0x40};
+    uint64_t offset = 12345;
+    char *armor = NULL;
+    CHECK(otppad_armor_generate("v0.3.53", chksum, offset, ct, sizeof(ct),
+                                &armor) == 0,
+          "armor generate");
+    CHECK(armor != NULL && strstr(armor, "BEGIN OTP MESSAGE") != NULL,
+          "armor has begin marker");
+
+    char parsed_chk[OTPPAD_CHKSUM_HEX_LEN + 1];
+    uint64_t parsed_off;
+    char parsed_b64[8192];
+    CHECK(otppad_armor_parse(armor, parsed_chk, &parsed_off, parsed_b64,
+                             sizeof(parsed_b64)) == 0,
+          "armor parse");
+    CHECK(strcmp(parsed_chk, chksum) == 0, "armor chksum round-trip");
+    CHECK(parsed_off == offset, "armor offset round-trip");
+
+    int dlen = 0;
+    unsigned char *dec = otppad_base64_decode(parsed_b64, &dlen);
+    CHECK(dec != NULL && dlen == (int)sizeof(ct), "armor b64 length");
+    CHECK(dec && memcmp(dec, ct, sizeof(ct)) == 0, "armor ciphertext round-trip");
+    free(armor);
+    free(dec);
+}
+
+static void test_bin_header(void) {
+    otppad_bin_header_t hdr;
+    memset(&hdr, 0, sizeof(hdr));
+    memcpy(hdr.magic, OTPPAD_MAGIC, OTPPAD_MAGIC_LEN);
+    hdr.version = OTPPAD_FORMAT_VERSION;
+    memset(hdr.pad_chksum, 0xab, OTPPAD_CHKSUM_BIN_LEN);
+    hdr.pad_offset = 999;
+    hdr.file_mode = 0644;
+    hdr.file_size = 4096;
+
+    const char *path = "test_bin_header.tmp";
+    FILE *fp = fopen(path, "wb");
+    CHECK(fp != NULL, "open bin header tmp for write");
+    CHECK(otppad_bin_header_write(fp, &hdr) == 0, "bin header write");
+    fclose(fp);
+
+    fp = fopen(path, "rb");
+    CHECK(fp != NULL, "open bin header tmp for read");
+    otppad_bin_header_t hdr2;
+    CHECK(otppad_bin_header_read(fp, &hdr2) == 0, "bin header read");
+    fclose(fp);
+    unlink(path);
+
+    CHECK(hdr2.version == hdr.version, "bin header version");
+    CHECK(hdr2.pad_offset == hdr.pad_offset, "bin header offset");
+    CHECK(hdr2.file_mode == hdr.file_mode, "bin header file_mode");
+    CHECK(hdr2.file_size == hdr.file_size, "bin header file_size");
+    CHECK(memcmp(hdr2.pad_chksum, hdr.pad_chksum, OTPPAD_CHKSUM_BIN_LEN) == 0,
+          "bin header chksum");
+    CHECK(otppad_bin_is_magic((const unsigned char *)hdr2.magic, 4),
+          "bin is_magic");
+}
+
+static void test_state(void) {
+    const char *dir = "test_state_dir.tmp";
+    mkdir(dir, 0755);
+    const char *chksum =
+        "333e9902db839d9d7f1f6aaa30f392a77c9abd011dd6274d9d3cf167361a789e";
+
+    uint64_t off;
+    CHECK(otppad_state_read(dir, chksum, &off) != 0, "state read missing fails");
+
+    CHECK(otppad_state_write(dir, chksum, 42) == 0, "state write");
+    CHECK(otppad_state_read(dir, chksum, &off) == 0, "state read");
+    CHECK(off == 42, "state value");
+
+    CHECK(otppad_state_write(dir, chksum, 1000) == 0, "state overwrite");
+    CHECK(otppad_state_read(dir, chksum, &off) == 0, "state read 2");
+    CHECK(off == 1000, "state value 2");
+
+    /* cleanup */
+    char path[1024];
+    snprintf(path, sizeof(path), "%s/%s.state", dir, chksum);
+    unlink(path);
+    rmdir(dir);
+}
+
+static void test_checksum(void) {
+    /* Build a tiny pad: 64 bytes, first 32 are the "key", rest arbitrary. */
+    const char *dir = "test_chksum_dir.tmp";
+    const char *chksum_expected =
+        "333e9902db839d9d7f1f6aaa30f392a77c9abd011dd6274d9d3cf167361a789e";
+    mkdir(dir, 0755);
+
+    /* Use the real test pad if it exists; otherwise skip this test. */
+    const char *real_pad =
+        "/media/user/Music/pads/333e9902db839d9d7f1f6aaa30f392a77c9abd011dd6274d9d3cf167361a789e.pad";
+    FILE *fp = fopen(real_pad, "rb");
+    if (!fp) {
+        printf("ok: checksum test skipped (no real pad at %s)\n", real_pad);
+        rmdir(dir);
+        return;
+    }
+    fclose(fp);
+
+    char chk[OTPPAD_CHKSUM_HEX_LEN + 1];
+    CHECK(otppad_checksum(real_pad, chk) == 0, "checksum computes");
+    CHECK(strcmp(chk, chksum_expected) == 0,
+          "checksum matches expected (bit-compatible with otp)");
+
+    rmdir(dir);
+}
+
+int main(void) {
+    test_xor();
+    test_base64();
+    test_padding();
+    test_armor();
+    test_bin_header();
+    test_state();
+    test_checksum();
+
+    if (failures == 0) {
+        printf("\nALL TESTS PASSED\n");
+        return 0;
+    }
+    printf("\n%d TEST(S) FAILED\n", failures);
+    return 1;
+}

packaging/qubes/allow_nostr_dom0.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+# Run in dom0 to allow the "nostr" qube to call n_signer without a Qubes popup.
+
+set -euo pipefail
+
+POLICY_FILE="/etc/qubes/policy.d/40-nsigner.policy"
+SIGNER_QUBE="nostr_signer"
+CALLER_QUBE="nostr"
+SIGNER_TAG="nsigner-signer"
+
+echo "Installing n_signer qrexec policy..."
+sudo mkdir -p /etc/qubes/policy.d
+sudo tee "$POLICY_FILE" >/dev/null <<EOF
+# Qubes OS qrexec policy for nsigner
+qubes.NsignerRpc * ai @tag:${SIGNER_TAG} allow target=${SIGNER_QUBE}
+qubes.NsignerRpc * ${CALLER_QUBE} @tag:${SIGNER_TAG} allow target=${SIGNER_QUBE}
+qubes.NsignerRpc * @anyvm @tag:${SIGNER_TAG} ask default_target=${SIGNER_QUBE}
+qubes.NsignerRpc * @anyvm @anyvm deny
+EOF
+sudo chmod 0644 "$POLICY_FILE"
+
+echo "Tagging ${SIGNER_QUBE} as ${SIGNER_TAG}..."
+qvm-tags "$SIGNER_QUBE" add "$SIGNER_TAG"
+
+echo
+echo "Installed policy:"
+sudo cat "$POLICY_FILE"
+echo
+echo "Tags on ${SIGNER_QUBE}:"
+qvm-tags "$SIGNER_QUBE" list
+echo
+echo "Done. Calls from ${CALLER_QUBE} to ${SIGNER_QUBE} are now allowed without a Qubes popup."

plans/algorithm_based_api.md

@@ -0,0 +1,387 @@
+# Proposal: Algorithm-Based API + New Policy Model
+
+## 1. Problem
+
+The current API keys off **roles** that bundle three concepts together:
+- **Algorithm** (curve: secp256k1, ed25519, ml-dsa-65, etc.)
+- **Purpose** (nostr, ssh, age, pq-sig, pq-kem)
+- **Derivation index** (nostr_index or role_path)
+
+The caller must know the role name and the role's configuration determines the algorithm. This is unintuitive — a caller that wants to "sign something with ed25519" shouldn't need to know that the operator named the role "ssh_main" and configured it with purpose=ssh.
+
+The purpose field is really a **policy/enforcement constraint**, not something the caller should care about. The caller knows what operation they want (sign, verify, encapsulate) and what algorithm they want to use. The signer's job is to check whether that combination is allowed and whether the caller is approved.
+
+## 2. Proposed API shape
+
+### 2.1 Core principle: verb + algorithm, not verb + role
+
+The caller specifies:
+- **What** they want to do (the verb)
+- **Which algorithm** they want to use
+- **Which key** (by derivation index)
+
+The signer determines:
+- Whether the verb+algorithm combination is valid (enforcement)
+- Whether the caller is approved (policy)
+- Derives the key on demand from the mnemonic
+
+### 2.2 Verbs
+
+Simplify to operation-based verbs. The algorithm is a parameter, not implicit in the verb name.
+
+| Verb | Description | Algorithm parameter | Key parameter |
+|---|---|---|---|
+| `get_public_key` | Get public key for a derived key | `algorithm` | `index` |
+| `sign` | Sign arbitrary bytes | `algorithm` | `index` |
+| `verify` | Verify a signature | `algorithm` | `index` (or `public_key`) |
+| `encapsulate` | KEM encapsulation | `algorithm` | `public_key` (peer's) |
+| `decapsulate` | KEM decapsulation | `algorithm` | `index` |
+| `derive_shared_secret` | ECDH key agreement (x25519) | `algorithm` | `index` + `peer_public_key` |
+| `sign_event` | Sign a Nostr event (secp256k1 only) | — (always secp256k1) | `index` |
+| `nip44_encrypt` | NIP-44 encrypt (secp256k1 only) | — | `index` + `peer_pubkey` |
+| `nip44_decrypt` | NIP-44 decrypt (secp256k1 only) | — | `index` + `peer_pubkey` |
+| `nip04_encrypt` | NIP-04 encrypt (secp256k1 only) | — | `index` + `peer_pubkey` |
+| `nip04_decrypt` | NIP-04 decrypt (secp256k1 only) | — | `index` + `peer_pubkey` |
+| `mine_event` | Mine + sign Nostr event (secp256k1 only) | — | `index` |
+
+The Nostr-specific verbs (`sign_event`, `nip44_*`, `nip04_*`, `mine_event`) are inherently secp256k1 — that's a protocol requirement of Nostr, not a policy choice. They don't take an `algorithm` parameter. The generic verbs (`sign`, `verify`, `encapsulate`, `decapsulate`, `derive_shared_secret`) take an `algorithm` parameter.
+
+### 2.3 Request format
+
+**Generic sign (any signature algorithm):**
+```json
+{
+  "id": "1",
+  "method": "sign",
+  "params": [
+    "68656c6c6f",
+    {
+      "algorithm": "ml-dsa-65",
+      "index": 0
+    }
+  ]
+}
+```
+- First param: message bytes as hex
+- Second param: options with `algorithm` and `index`
+
+**Response:**
+```json
+{
+  "id": "1",
+  "result": {
+    "signature": "<hex>",
+    "algorithm": "ml-dsa-65",
+    "key_id": "a1b2c3d4e5f6a1b2"
+  }
+}
+```
+
+**Get public key (any algorithm):**
+```json
+{
+  "id": "2",
+  "method": "get_public_key",
+  "params": [
+    {
+      "algorithm": "ed25519",
+      "index": 0
+    }
+  ]
+}
+```
+
+**Response:**
+```json
+{
+  "id": "2",
+  "result": {
+    "algorithm": "ed25519",
+    "public_key": "<hex>",
+    "key_id": "a1b2c3d4e5f6a1b2"
+  }
+}
+```
+
+**KEM encapsulate:**
+```json
+{
+  "id": "3",
+  "method": "encapsulate",
+  "params": [
+    "<peer_pubkey_hex>",
+    {
+      "algorithm": "ml-kem-768"
+    }
+  ]
+}
+```
+
+**KEM decapsulate:**
+```json
+{
+  "id": "4",
+  "method": "decapsulate",
+  "params": [
+    "<ciphertext_hex>",
+    {
+      "algorithm": "ml-kem-768",
+      "index": 0
+    }
+  ]
+}
+```
+
+**ECDH shared secret (x25519):**
+```json
+{
+  "id": "5",
+  "method": "derive_shared_secret",
+  "params": [
+    "<peer_pubkey_hex>",
+    {
+      "algorithm": "x25519",
+      "index": 0
+    }
+  ]
+}
+```
+
+**Nostr sign_event (unchanged, always secp256k1):**
+```json
+{
+  "id": "6",
+  "method": "sign_event",
+  "params": [
+    "<event_json>",
+    {
+      "index": 0
+    }
+  ]
+}
+```
+
+### 2.4 Algorithm names
+
+| String | Algorithm | Key type |
+|---|---|---|
+| `secp256k1` | secp256k1 (Schnorr) | Signature |
+| `ed25519` | ed25519 | Signature |
+| `ml-dsa-65` | ML-DSA-65 (FIPS 204) | Signature |
+| `slh-dsa-128s` | SLH-DSA-128s (FIPS 205) | Signature |
+| `x25519` | X25519 (ECDH) | Key agreement |
+| `ml-kem-768` | ML-KEM-768 (FIPS 203) | KEM |
+
+### 2.5 Key identification
+
+Keys are identified by **algorithm + index** instead of role names. The index is the BIP-44 account field in the derivation path:
+
+| Algorithm | Derivation path for index N |
+|---|---|
+| secp256k1 | `m/44'/1237'/N'/0/0` (NIP-06, unchanged) |
+| ed25519 | `m/44'/102001'/N'/0'/0'` |
+| x25519 | `m/44'/102002'/N'/0'/0'` |
+| ml-dsa-65 | `m/44'/102003'/N'/0'/0'` |
+| slh-dsa-128s | `m/44'/102004'/N'/0'/0'` |
+| ml-kem-768 | `m/44'/102005'/N'/0'/0'` |
+
+The `key_id` (first 16 hex chars of the public key) provides a short human-readable identifier for display at the approval prompt.
+
+### 2.6 Backward compatibility
+
+The existing role-based API continues to work for Nostr clients:
+- `sign_event` with `{role: "main"}` or `{nostr_index: 0}` — unchanged
+- `nip44_encrypt`, `nip04_decrypt`, etc. — unchanged
+- `get_public_key` with `{role: "main"}` — returns plain hex (secp256k1 backward compat)
+
+The new algorithm-based API is additive — new verbs (`sign`, `verify`, `encapsulate`, `decapsulate`, `derive_shared_secret`) use the algorithm parameter. Old verbs keep their role-based selectors.
+
+## 3. Proposed policy model
+
+### 3.1 Current model (role-based)
+
+From [`plans/deny_by_default_approvals.md`](plans/deny_by_default_approvals.md):
+- Roles are pre-configured at startup with purpose+curve+index
+- Policy entries approve callers for specific roles
+- `--preapprove caller=uid:1000,role=main,verb=sign_event`
+- Prompt `[a]` approves the caller for the role
+
+### 3.2 New model (algorithm-based)
+
+Policy entries approve callers for **algorithm + index ranges + verbs**:
+
+**Policy entry structure:**
+```
+caller: <caller_id>
+algorithms: [ed25519, ml-dsa-65]     # which algorithms this caller can use
+index_range: 0-4                      # which derivation indices (or * for any)
+verbs: [sign, verify, get_public_key] # which verbs
+prompt: first_per_boot                # prompt behavior
+```
+
+**`--preapprove` CLI flag:**
+```bash
+nsigner --preapprove caller=uid:1000,algorithm=ed25519,index=0-4,verb=sign
+nsigner --preapprove caller=uid:1000,algorithm=ml-dsa-65,index=0,verb=sign,verify
+nsigner --preapprove caller=pubkey:abc...,algorithm=ml-kem-768,index=0,verb=decapsulate
+```
+
+**Prompt display:**
+When a caller requests `sign` with `algorithm=ml-dsa-65, index=0`, the prompt shows:
+```
+Caller: uid:1000
+Action: sign with ML-DSA-65
+Key:    index 0 (key_id: a1b2c3d4e5f6a1b2)
+[a] approve  [d] deny
+```
+
+The operator approves the caller for that algorithm+index+verb combination. Subsequent requests with the same combination are auto-approved (if `prompt: first_per_boot`).
+
+### 3.3 Nostr verbs policy
+
+Nostr verbs (`sign_event`, `nip44_*`, `nip04_*`, `mine_event`) are always secp256k1. They can be policy-keyed as either:
+- **Algorithm-based**: `algorithm=secp256k1, verb=sign_event, index=0` (new style)
+- **Role-based**: `role=main, verb=sign_event` (old style, backward compat)
+
+Both resolve to the same key. The signer accepts both selector forms.
+
+### 3.4 Wildcards
+
+| Pattern | Meaning |
+|---|---|
+| `algorithm=*` | Any algorithm |
+| `index=*` | Any index |
+| `index=0-4` | Indices 0 through 4 inclusive |
+| `verb=*` | Any verb valid for the algorithm |
+
+Wildcards make policy more compact but less precise. The default is no wildcards (explicit per-algorithm, per-index, per-verb).
+
+### 3.5 Enforcement matrix
+
+The signer checks verb+algorithm validity (regardless of policy):
+
+| Verb | Valid algorithms | Notes |
+|---|---|---|
+| `sign` | secp256k1, ed25519, ml-dsa-65, slh-dsa-128s | Generic signing |
+| `verify` | secp256k1, ed25519, ml-dsa-65, slh-dsa-128s | Generic verification |
+| `encapsulate` | ml-kem-768 | KEM encapsulation |
+| `decapsulate` | ml-kem-768 | KEM decapsulation |
+| `derive_shared_secret` | x25519 | ECDH key agreement |
+| `get_public_key` | all | Any algorithm |
+| `sign_event` | secp256k1 (implicit) | Nostr protocol requirement |
+| `nip44_encrypt` | secp256k1 (implicit) | Nostr protocol requirement |
+| `nip44_decrypt` | secp256k1 (implicit) | Nostr protocol requirement |
+| `nip04_encrypt` | secp256k1 (implicit) | Nostr protocol requirement |
+| `nip04_decrypt` | secp256k1 (implicit) | Nostr protocol requirement |
+| `mine_event` | secp256k1 (implicit) | Nostr protocol requirement |
+
+If a caller requests `sign` with `algorithm=x25519`, the signer rejects with `algorithm_not_supported_for_verb` — x25519 is a key agreement algorithm, not a signature algorithm.
+
+### 3.6 No purpose field
+
+The `purpose` field is **removed entirely**. There is no `purpose` in the API, no purpose in enforcement, no purpose in policy. The role_purpose_t enum and all purpose-related code is removed from the codebase.
+
+Enforcement is purely verb+algorithm based — the signer checks whether the requested verb is valid for the requested algorithm. No "purpose mismatch" errors, no purpose in policy entries, no purpose in role configuration.
+
+Roles (if kept for backward compat with existing Nostr clients) are keyed on algorithm+index only, not purpose+curve.
+
+## 4. Migration path
+
+### Phase A: Add algorithm-based verbs (additive, no breaking changes)
+
+1. Add new verbs: `sign`, `verify`, `encapsulate`, `decapsulate`, `derive_shared_secret`
+2. These accept `{algorithm, index}` in the options
+3. Old verbs (`sign_data`, `ssh_sign`, `kem_encapsulate`, `kem_decapsulate`) become aliases that map to the new verbs
+4. Old role-based selectors continue to work on all verbs
+5. Policy model extended to support algorithm-based entries alongside role-based entries
+
+### Phase B: Deprecate old verb names (optional, future)
+
+1. `sign_data` → `sign`
+2. `ssh_sign` → `sign` (with `algorithm=ed25519`)
+3. `kem_encapsulate` → `encapsulate`
+4. `kem_decapsulate` → `decapsulate`
+5. `verify_signature` → `verify`
+6. Old names still work but are documented as deprecated
+
+### Phase C: Remove purpose from enforcement (optional, future)
+
+1. Purpose becomes pure metadata
+2. Enforcement only checks verb+algorithm validity
+3. Roles become optional (algorithm+index is the primary key selector)
+
+## 5. Example: full session with new API
+
+### Operator starts n_signer:
+```bash
+nsigner --preapprove caller=uid:1000,algorithm=ed25519,index=0,verb=sign,verify,get_public_key \
+        --preapprove caller=uid:1000,algorithm=ml-dsa-65,index=0,verb=sign,verify,get_public_key \
+        --preapprove caller=uid:1000,algorithm=ml-kem-768,index=0,verb=decapsulate,get_public_key
+```
+
+### Client gets an ed25519 public key:
+```json
+{"id":"1","method":"get_public_key","params":[{"algorithm":"ed25519","index":0}]}
+→ {"id":"1","result":{"algorithm":"ed25519","public_key":"...","key_id":"a1b2..."}}
+```
+
+### Client signs a message with ed25519:
+```json
+{"id":"2","method":"sign","params":["68656c6c6f",{"algorithm":"ed25519","index":0}]}
+→ {"id":"2","result":{"signature":"...","algorithm":"ed25519","key_id":"a1b2..."}}
+```
+
+### Client signs a message with ML-DSA-65:
+```json
+{"id":"3","method":"sign","params":["68656c6c6f",{"algorithm":"ml-dsa-65","index":0}]}
+→ {"id":"3","result":{"signature":"...","algorithm":"ml-dsa-65","key_id":"c3d4..."}}
+```
+
+### Client encapsulates with ML-KEM-768 (using peer's public key):
+```json
+{"id":"4","method":"encapsulate","params":["<peer_pubkey_hex>",{"algorithm":"ml-kem-768"}]}
+→ {"id":"4","result":{"ciphertext":"...","shared_secret":"...","algorithm":"ml-kem-768"}}
+```
+
+### Client decapsulates (signer side, using its ML-KEM private key):
+```json
+{"id":"5","method":"decapsulate","params":["<ciphertext_hex>",{"algorithm":"ml-kem-768","index":0}]}
+→ {"id":"5","result":{"shared_secret":"...","algorithm":"ml-kem-768"}}
+```
+
+### Client signs a Nostr event (backward compatible):
+```json
+{"id":"6","method":"sign_event","params":["<event_json>",{"index":0}]}
+→ {"id":"6","result":"<signed_event_json>"}
+```
+
+## 6. Comparison: old vs new
+
+| Aspect | Old (role-based) | New (algorithm-based) |
+|---|---|---|
+| Caller specifies | Role name | Algorithm + index |
+| Algorithm determined by | Role's configured curve | Explicit `algorithm` parameter |
+| Purpose | Enforcement constraint | Optional metadata |
+| Policy unit | Role | Algorithm + index + verb |
+| Nostr verbs | Role-based selector | Index-based (algorithm implicit) |
+| Generic verbs | `sign_data` (role-based) | `sign` (algorithm-based) |
+| Key derivation | Role's index/path | Algorithm's derivation path + index |
+
+## 7. Decisions
+
+1. **secp256k1 `sign` — offer both Schnorr and ECDSA.** The `sign` verb accepts an optional `scheme` parameter for secp256k1: `"scheme": "schnorr"` (default, BIP-340) or `"scheme": "ecdsa"`. Other algorithms have one signature scheme each and ignore this parameter.
+
+2. **Index is per-algorithm.** Each algorithm has its own derivation path prefix (coin type), so "index 0" for ed25519 and "index 0" for ml-dsa-65 are different keys. This is the only sensible model — different algorithms need different key material.
+
+3. **Key selector is `index` only.** No `role_path` support for the new verbs. The `index` parameter maps to the account field in the standard BIP-44 derivation path. This is simpler, covers all normal use cases, and is easy to policy-gate. Arbitrary derivation paths can be a future advanced feature if needed.
+
+4. **`verify` uses the signer's own derived public key.** The `verify` verb takes `algorithm` + `index` (same as `sign`) and verifies a signature against the signer's own derived public key. This is useful for round-trip testing (client signs, then verifies). The signer does NOT verify arbitrary external signatures with a `public_key` parameter — that's a client-side operation that doesn't need the signer.
+
+5. **Remove the `purpose` field entirely.** No `purpose` in the API, no purpose in enforcement, no purpose in policy. Enforcement is purely verb+algorithm based:
+   - `sign` works with any signature algorithm (secp256k1, ed25519, ml-dsa-65, slh-dsa-128s)
+   - `encapsulate`/`decapsulate` work with ml-kem-768
+   - `derive_shared_secret` works with x25519
+   - `sign_event`/`nip44_*`/`nip04_*`/`mine_event` always use secp256k1 (Nostr protocol requirement, not a purpose check)
+   - `get_public_key` works with any algorithm
+
+   The `role_purpose_t` enum and all purpose-related code is removed. Roles (if kept for backward compat) are keyed on algorithm+index only.

plans/http_wss_listener.md

@@ -0,0 +1,274 @@
+# Plan: HTTP and WebSocket (WSS) Listener Modes for n_signer
+
+## Goal
+
+Add two new listener modes to n_signer so that standard HTTP clients (curl) and
+WebSocket clients (browsers, relay-style tools) can send JSON-RPC requests
+directly, without the custom 4-byte length-prefixed framing.
+
+## Current state
+
+n_signer supports these listener modes:
+- `unix` — abstract namespace Unix socket, 4-byte framed JSON
+- `stdio` — stdin/stdout, 4-byte framed JSON, one request per invocation
+- `qrexec` — same as stdio but with `QREXEC_REMOTE_DOMAIN` caller identity
+- `tcp:HOST:PORT` — TCP, 4-byte framed JSON
+
+All modes use the same dispatcher (`dispatcher_handle_request`) which takes a
+JSON string and returns a JSON string. The only difference between modes is the
+transport framing and caller-identity extraction.
+
+## Proposed modes
+
+### HTTP mode: `--listen http:HOST:PORT`
+
+**Protocol:** HTTP/1.1 POST with JSON body → JSON response.
+
+```
+POST / HTTP/1.1
+Content-Type: application/json
+
+{"id":"1","method":"otp_encrypt","params":["SGVsbG8=",{"encoding":"ascii"}]}
+
+HTTP/1.1 200 OK
+Content-Type: application/json
+
+{"id":"1","result":"{...}"}
+```
+
+**curl example:**
+```bash
+curl -s -X POST http://127.0.0.1:11111/ \
+  -H 'Content-Type: application/json' \
+  -d '{"id":"1","method":"get_public_key","params":[{"role":"main"}]}'
+```
+
+**Implementation:**
+- Parse the HTTP request line + headers (minimal parser — just enough for POST)
+- Read the Content-Length bytes as the JSON-RPC request
+- Call `dispatcher_handle_request()`
+- Write the HTTP response with the JSON result
+
+**Difficulty: Low.** The HTTP parser can be minimal (~100 lines). No need for
+a full HTTP server — just POST with a JSON body. No chunked encoding, no
+keep-alive, no static file serving. One request per connection (connection
+close after response), or simple keep-alive loop.
+
+**Caller identity:** `tcp:<peer-addr>` (same as TCP mode). No `QREXEC_REMOTE_DOMAIN`.
+
+**HTTPS variant:** `--listen https:HOST:PORT` wraps the HTTP listener in TLS.
+Requires `--tls-cert <path>` and `--tls-key <path>` flags. OpenSSL is already
+linked. The HTTP parser stays the same; TLS is layered underneath (accept
+connection → TLS handshake → then HTTP). See Phase 3 below.
+
+### WebSocket mode: `--listen wss:HOST:PORT` (or `ws:HOST:PORT`)
+
+**Protocol:** WebSocket with JSON text frames.
+
+```
+Client → Server: text frame with JSON-RPC request
+Server → Client: text frame with JSON-RPC response
+```
+
+**Browser example:**
+```javascript
+const ws = new WebSocket("ws://127.0.0.1:11111");
+ws.onopen = () => {
+  ws.send(JSON.stringify({id:"1", method:"get_public_key", params:[{role:"main"}]}));
+};
+ws.onmessage = (e) => {
+  console.log(JSON.parse(e.data));
+};
+```
+
+**Implementation:**
+- HTTP upgrade handshake (Sec-WebSocket-Key → Sec-WebSocket-Accept)
+- WebSocket frame parser (opcode, mask, payload length — 7/16/64 bit)
+- Text frames (opcode 0x1) carry JSON-RPC requests
+- Response as text frames (opcode 0x1, unmasked from server)
+- One JSON-RPC request per text frame; one response per request
+
+**Difficulty: Medium.** The WebSocket handshake is straightforward (SHA-1 +
+base64 of the key + magic GUID). The frame parser needs to handle:
+- 7-bit, 16-bit, and 64-bit payload lengths
+- Client-to-server masking (XOR with 4-byte mask)
+- Ping/pong frames (opcode 0x9/0xA)
+- Close frame (opcode 0x8)
+- Fragmentation (continuation frames, opcode 0x0) — can defer/skip for v1
+
+A minimal implementation is ~200-300 lines. No need for a full RFC 6455
+compliance — just enough for curl, browsers, and common WebSocket clients.
+
+**WSS (TLS) variant:** `wss:HOST:PORT` wraps the WebSocket in TLS. This
+requires linking against OpenSSL (already a dependency) and adding TLS
+handshake + certificate handling. Difficulty: Medium-High due to cert
+management. For v1, `ws:` (plaintext) is sufficient for localhost/FIPS-mesh
+use; `wss:` can be added later.
+
+**Caller identity:** `ws:<peer-addr>` or `wss:<peer-addr>`.
+
+## Security concerns
+
+### 1. Network exposure
+
+**Unix sockets** are only accessible from the same host/qube — no network
+exposure. **HTTP/WS** listeners bind to a TCP port, which is potentially
+reachable from other hosts/qubes on the network.
+
+**Mitigation:**
+- Default bind address: `127.0.0.1` (localhost only), not `[::]` (all
+  interfaces). The user must explicitly pass `--listen http:0.0.0.0:11111` to
+  expose it.
+- The existing policy/approval system is the real gate — network access alone
+  doesn't grant signing. Unknown callers get `PROMPT_EVERY_REQUEST` by default.
+
+### 2. No authentication in HTTP/WS mode
+
+The current TCP mode has no authentication either — it relies on the
+policy/approval prompt. HTTP/WS would be the same. Anyone who can reach the
+port can send requests, but they still need approval for sensitive operations.
+
+**Mitigation:**
+- The `--auth required` mode (auth envelopes) could be extended to HTTP/WS.
+  The client would include a signed auth envelope in an HTTP header
+  (e.g. `X-Nsigner-Auth: <envelope>`) or as a WebSocket subprotocol header.
+- For v1, rely on localhost binding + policy/approval prompts, same as TCP.
+
+### 3. CORS for browser access
+
+If the WebSocket listener is accessed from a browser running on a different
+origin, CORS headers are needed for the HTTP upgrade handshake.
+
+**Mitigation:**
+- Add `Access-Control-Allow-Origin: *` to the WebSocket upgrade response
+  (the policy/approval system is the real security boundary, not CORS).
+- Or restrict to same-origin only (no CORS header → browser blocks
+  cross-origin).
+
+### 4. Request size limits — MUST be raised for OTP blob encryption
+
+The current `SERVER_MAX_MSG_SIZE` is 65536 bytes (64KB). This is too small
+for OTP encryption of images or blobs:
+
+- A 48KB image → base64 in JSON param = ~64KB → hits the limit
+- A 1MB image → base64 = ~1.33MB → way over
+- OTP Padmé padding rounds up to the next power of 2, and the response
+  contains the base64-encoded ciphertext, which is even larger
+
+**This is a pre-existing limitation that affects ALL transport modes**, not
+just HTTP/WS. It should be fixed before or alongside the HTTP/WS work.
+
+**Proposed change:** raise `SERVER_MAX_MSG_SIZE` to 16MB (16777216). This
+accommodates:
+- Up to ~12MB plaintext (base64 = ~16MB in the JSON param)
+- The OTP response (base64-encoded padded ciphertext) for the same
+- The `stdin_buf[SERVER_MAX_MSG_SIZE + 1]` stack buffer in `client_main`
+  should be changed to a heap allocation to avoid a 16MB stack frame
+
+The `transport_recv_framed` function already takes a max-size parameter, so
+the change is: update the constant, change the stack buffer to malloc, and
+verify the dispatcher doesn't have other hardcoded size assumptions.
+
+**For HTTP/WS:** enforce the same `SERVER_MAX_MSG_SIZE` limit via
+`Content-Length` checking in the HTTP parser.
+
+### 5. TLS for WSS
+
+For `wss:` mode, TLS is required. This means:
+- Certificate management (self-signed for local/FIPS mesh, or CA-signed for
+  public-facing).
+- The signer would need a `--tls-cert` and `--tls-key` flag.
+- Pinning: clients should verify the cert fingerprint, not just trust the CA.
+
+**For v1:** skip WSS/TLS. Provide `ws:` (plaintext) only, suitable for
+localhost and FIPS mesh (which has its own network-level isolation). Add
+`wss:` later when there's a real public-facing use case.
+
+### 6. Connection flooding
+
+HTTP/WS listeners are susceptible to connection flooding (many open
+connections, slowloris-style attacks). The current single-threaded poll loop
+handles one connection at a time, which naturally limits flood impact but
+also limits throughput.
+
+**Mitigation:**
+- Connection timeout (close idle connections after N seconds).
+- Max connections limit.
+- For v1, the single-threaded model is fine — it's a signer, not a web server.
+
+## Implementation plan
+
+### Phase 0: Raise SERVER_MAX_MSG_SIZE (prerequisite)
+
+- [ ] Change `SERVER_MAX_MSG_SIZE` from 65536 to 16777216 (16MB) in all
+      `.c` files where it's defined (the headerless-decls pattern means it's
+      redefined in every file).
+- [ ] Change the `stdin_buf[SERVER_MAX_MSG_SIZE + 1]` stack buffer in
+      `client_main` to a heap allocation (malloc/free) to avoid a 16MB stack
+      frame.
+- [ ] Verify `transport_recv_framed` handles the larger size correctly (it
+      already takes max-size as a parameter).
+- [ ] Test with a large OTP encrypt/decrypt round-trip (e.g. 1MB plaintext).
+
+### Phase 1: HTTP listener mode
+
+- [ ] Add `NSIGNER_LISTEN_HTTP` to the listen mode enum.
+- [ ] Parse `--listen http:HOST:PORT` in the CLI flag parser.
+- [ ] Implement a minimal HTTP/1.1 parser in `src/http_listener.c`:
+  - Read request line (method, path, HTTP version)
+  - Read headers (only need Content-Length)
+  - Read body (Content-Length bytes)
+  - Reject non-POST methods with 405
+  - Reject oversized bodies with 413
+- [ ] Call `dispatcher_handle_request()` with the body, write JSON response
+  with `200 OK` + `Content-Type: application/json`.
+- [ ] Caller identity: `http:<peer-ip>:<peer-port>`.
+- [ ] Default bind: `127.0.0.1` (not `[::]`).
+- [ ] Add to interactive transport menu as option 4.
+- [ ] Test with curl.
+
+### Phase 2: WebSocket listener mode
+
+- [ ] Add `NSIGNER_LISTEN_WS` to the listen mode enum.
+- [ ] Parse `--listen ws:HOST:PORT` in the CLI flag parser.
+- [ ] Implement WebSocket handshake + frame parser in `src/ws_listener.c`:
+  - HTTP upgrade handshake (Sec-WebSocket-Key → Accept)
+  - Frame parser (opcode, mask, payload length)
+  - Text frames → JSON-RPC request → dispatcher → text frame response
+  - Ping/pong handling
+  - Close frame handling
+- [ ] Caller identity: `ws:<peer-ip>:<peer-port>`.
+- [ ] Default bind: `127.0.0.1`.
+- [ ] Add to interactive transport menu as option 5.
+- [ ] Test with a browser or `websocat`.
+
+### Phase 3: TLS mode (HTTPS + WSS)
+
+- [ ] Add `--tls-cert <path>` and `--tls-key <path>` CLI flags.
+- [ ] Add `--listen https:HOST:PORT` — HTTP listener wrapped in TLS.
+- [ ] Add `--listen wss:HOST:PORT` — WebSocket listener wrapped in TLS.
+- [ ] TLS handshake via OpenSSL (already a dependency):
+  - Load cert/key from files
+  - `SSL_CTX_new(TLS_server_method())`
+  - `SSL_CTX_use_certificate_file()` / `SSL_CTX_use_PrivateKey_file()`
+  - Per-connection: `SSL_new()` → `SSL_set_fd()` → `SSL_accept()`
+  - Replace read/write calls with `SSL_read()` / `SSL_write()`
+- [ ] Self-signed cert generation helper (or document `openssl req` command).
+- [ ] Certificate pinning guidance for clients (verify fingerprint, not just CA).
+- [ ] curl usage: `curl --cacert <cert.pem>` or `curl -k` (insecure, for testing).
+- [ ] Not strictly needed for localhost/FIPS mesh use, but good for defense in depth.
+
+## Difficulty assessment
+
+| Mode | Difficulty | New code | Dependencies | Risk |
+|---|---|---|---|---|
+| HTTP | Low | ~150 lines | None (minimal parser) | Low — simple POST/JSON |
+| WS | Medium | ~300 lines | None (minimal frame parser) | Medium — frame parsing edge cases |
+| HTTPS | Medium | ~150 + ~80 TLS | OpenSSL (already linked) | Medium — cert management |
+| WSS | Medium-High | ~300 + ~80 TLS | OpenSSL (already linked) | Higher — cert + WS edge cases |
+
+## Recommendation
+
+Start with HTTP mode (Phase 1) — it's the simplest and immediately enables
+curl access. Add WebSocket (Phase 2) if browser access is needed. Defer WSS
+(Phase 3) until there's a real public-facing use case.

plans/interactive_transport_selection.md

@@ -0,0 +1,143 @@
+# Plan: Interactive multi-transport selection at startup
+
+Status: design / ready for review.
+
+Related:
+- [`README.md`](../README.md) §7 Transport, §8.3 Qubes OS qube, §9 Usage
+- [`src/main.c`](../src/main.c) — argument parsing, main loop, TUI
+- [`src/server.c`](../src/server.c) — `server_ctx_t`, `server_start`, `server_handle_one`
+- [`plans/qrexec_persistent_bridge.md`](qrexec_persistent_bridge.md) — bridge design
+
+---
+
+## 1. Motivation
+
+The current CLI has many transport flags (`--listen`, `--socket-name`, `--bridge-source-trusted`, `--auth`, `--allow-all`) that the user must know in advance. For interactive use, this is unfriendly — the user just wants to answer "how should other programs reach this signer?"
+
+Additionally, the user may want **multiple transports active simultaneously** (e.g. unix socket for local clients + TCP for FIPS mesh clients + qrexec bridge for other qubes). Today only one `--listen` mode is supported at a time.
+
+---
+
+## 2. Design
+
+### 2.1 Interactive transport menu at startup
+
+After mnemonic entry and before the running phase, if no `--listen` flag was given (i.e. interactive mode), present a multi-select menu:
+
+```text
+Transport — how should other programs reach this signer?
+Select one or more (space to toggle, enter to confirm):
+
+  [x] 1. Local Unix socket (same machine/qube)
+  [ ] 2. Qubes qrexec bridge (other qubes via qrexec, no network)
+  [ ] 3. TCP listener (FIPS mesh or local network)
+  [ ] 4. Qrexec one-shot (legacy, one request per invocation)
+
+  [a] select all
+
+  (at least one must be selected)
+```
+
+Each selected transport gets configured with sensible defaults:
+
+| Choice | What it starts | Defaults |
+|---|---|---|
+| 1. Unix socket | `--listen unix` | socket name `nsigner` (or random if collision) |
+| 2. Qrexec bridge | `--listen unix --bridge-source-trusted` | socket name `nsigner`, accepts qrexec preamble |
+| 3. TCP | `--listen tcp:[::]:11111` | bind all interfaces, port 11111 |
+| 4. Qrexec one-shot | `--listen qrexec` | one request via stdin, then exit |
+
+**Choices 1 and 2 can coexist** — they're both unix listeners, just with different identity handling. Choice 2 implies choice 1's socket. If both are selected, the bridge-source-trusted flag is set on the single unix listener (it handles both local and bridge connections).
+
+**Choice 3 (TCP) can coexist with 1+2** — it's a separate listener on a different fd.
+
+**Choice 4 (qrexec one-shot) is mutually exclusive** with all others — it uses stdin/stdout and exits after one request. If selected alone, it runs the one-shot path. If selected with others, it's ignored with a warning (or: the user is told it can't combine).
+
+### 2.2 Multi-listener architecture
+
+Currently `main()` creates one `server_ctx_t` and polls `server.listen_fd` + `STDIN_FILENO`. To support multiple listeners:
+
+- Create an array of `server_ctx_t` (up to 3: unix, tcp, and optionally a second unix for bridge — though 1+2 collapse into one).
+- Each `server_ctx_t` gets its own `server_start()`.
+- The poll loop expands to poll all listener fds + STDIN_FILENO.
+- When a listener fd has activity, call `server_handle_one()` on that context.
+- The TUI status display shows all active transports.
+
+```text
+Connections
+listen: unix @nsigner (bridge-source-trusted)
+listen: tcp [::]:11111
+client: nsigner --socket-name nsigner client '<json>'
+```
+
+### 2.3 Coexistence with CLI flags
+
+- If `--listen` is given on the command line, **skip the interactive menu** (automation/scripting path unchanged).
+- If no `--listen` is given and stdin is a TTY, **show the interactive menu**.
+- If no `--listen` is given and stdin is NOT a TTY, **default to unix socket** (current behavior, for `--mnemonic-stdin` / `--mnemonic-fd` supervised launches).
+
+This preserves backward compatibility: all existing flags and scripts work unchanged. The menu is purely an interactive convenience.
+
+### 2.4 TUI implementation
+
+The menu uses the existing TUI rendering helpers (`tui_render_content_screen`, `tui_print`). It appears after mnemonic acceptance and before the status display. Navigation:
+
+- `1`-`4` or space: toggle a choice
+- `a`: select all (except 4, which is mutually exclusive)
+- `a`: select all (except 4, which is mutually exclusive)
+- `enter`: confirm and proceed to running phase (at least one must be selected)
+
+After confirmation, the selected listeners are started and the status display renders.
+
+### 2.5 Security considerations
+
+- The menu is purely a UX layer — it doesn't change the security model. Each transport still goes through the same policy/approval pipeline.
+- `--bridge-source-trusted` is only set if the user explicitly selects the qrexec bridge option. It's never silently enabled.
+- TCP listener still requires auth envelopes (existing behavior).
+- The menu doesn't offer `--allow-all`; that remains a CLI flag for users who want it.
+
+---
+
+## 3. Implementation checklist
+
+### 3.1 Multi-listener support in `main.c`
+- [ ] Replace single `server_ctx_t server` with an array (e.g. `server_ctx_t servers[3]`).
+- [ ] Add a `server_count` variable.
+- [ ] Expand the poll loop to poll all `servers[i].listen_fd` + STDIN_FILENO.
+- [ ] On activity, call `server_handle_one(&servers[i], ...)` for the matching fd.
+- [ ] `server_stop()` all on shutdown.
+
+### 3.2 Interactive menu
+- [ ] Add `prompt_transport_selection()` function in `main.c` (after mnemonic load, before server start).
+- [ ] Returns a bitmask of selected transports.
+- [ ] Only called when `listen_mode` was not set by CLI and stdin is a TTY.
+- [ ] Uses `tui_render_content_screen` + `read_line_stdin` for input.
+
+### 3.3 Transport setup from menu selection
+- [ ] Unix: `server_init` + `server_start` with `NSIGNER_LISTEN_UNIX`, socket name `nsigner`.
+- [ ] Qrexec bridge: same as unix + `server_set_bridge_source_trusted(&server, 1)`.
+- [ ] TCP: `server_init` + `server_start` with `NSIGNER_LISTEN_TCP`, target `tcp:[::]:11111`.
+- [ ] Qrexec one-shot: existing `NSIGNER_LISTEN_QREXEC` path (stdin, one request, exit).
+
+### 3.4 TUI status display
+- [ ] Update `render_status()` to show multiple active listeners.
+- [ ] Show `(bridge-source-trusted)` annotation on unix listeners that have it.
+
+### 3.5 Testing
+- [ ] Interactive: start nsigner with no `--listen`, select unix+TCP, verify both listeners work.
+- [ ] Interactive: select qrexec bridge, verify bridge connections get `qubes:<vm>` identity.
+- [ ] CLI: `--listen tcp:[::]:11111` still works (skips menu).
+- [ ] CLI: `--listen unix --bridge-source-trusted` still works (skips menu).
+- [ ] Non-TTY: `--mnemonic-stdin` without `--listen` defaults to unix (no menu).
+
+---
+
+## 4. Open questions
+
+1. **Should the menu remember the last selection?** n_signer has no config files (by design). We could store the preference in an env var or a `/tmp` file, but that violates the zero-filesystem-footprint principle. **Decision: no persistence — the menu appears fresh each time.**
+
+2. **Should there be a hotkey to add/remove transports at runtime?** E.g. press `t` in the TUI to bring up the transport menu again. This is a nice-to-have but adds complexity. **Decision: defer — the menu is startup-only for now.**
+
+3. **TCP port selection in the menu?** The menu could ask for a port number if TCP is selected. **Decision: default to 11111, let the user override with `--listen tcp:...` if they need a different port. Keep the menu simple.**
+
+4. **Socket name selection?** Same — default to `nsigner`, override with `--socket-name` if needed. **Decision: default, no prompt.**

plans/mine_event_pow.md

@@ -0,0 +1,430 @@
+# Plan: Add `mine_event` Verb (NIP-13 Proof-of-Work) to n_signer
+
+## Executive Summary
+
+**Recommendation: Do NOT import event_miner as a subrepo or copy its code.**
+
+n_signer already has [`nip013.h`](resources/nostr_core_lib/nostr_core/nip013.h:1) and [`nip013.c`](resources/nostr_core_lib/nostr_core/nip013.c:1) in its `resources/nostr_core_lib/`. event_miner is a standalone CLI tool (~716 lines) whose useful logic is ~50 lines. The rest is CLI parsing, stdin/file I/O, signal handlers, and `exit()` calls that are inappropriate for a long-running server.
+
+Instead, we add a new `mine_event` verb to n_signer's existing dispatcher that:
+1. Mines PoW for a time budget (e.g., "mine for 30 seconds with 4 threads")
+2. Returns the **best result found** within that time — regardless of whether the target difficulty was reached
+3. Signs the event with the role's derived private key
+4. Returns the mined + signed event JSON along with metadata about the achieved difficulty
+
+## Why Not Subrepo or Copy?
+
+| Factor | Subrepo | Copy | New verb (recommended) |
+|--------|---------|------|----------------------|
+| Key management | event_miner takes raw nsec CLI arg | same | Uses n_signer's role table + key_store (secure, mlock'd) |
+| Architecture | CLI tool, calls exit() | same | Fits JSON-RPC dispatcher/enforcement/policy model |
+| Threading | Global vars, signal handlers, exit() | same | Clean detached thread per request, no globals |
+| Best-effort model | No — stops at target or max_attempts | same | Yes — returns best result within time budget |
+| Code reuse | ~50 lines useful | same | Rewrite ~150 lines for server-safe best-effort model |
+| Maintenance | Extra submodule to track | Drift risk | Single codebase, single nostr_core_lib |
+
+## Design Decisions
+
+- **Verb name**: `mine_event`
+- **Params**: `[event_json, {difficulty: N, threads: N, timeout_sec: N, ...role_selector}]`
+- **Dual termination model**: Both `timeout_sec` and `difficulty` are independent options. Either, both, or at least one must be specified:
+  - **Both set**: Mine until target reached OR timeout — return best result (with `target_reached` flag)
+  - **Only `timeout_sec`**: Mine for the full duration, return best result found
+  - **Only `difficulty`**: Mine until target reached, with a safety max timeout (e.g., 10 minutes) to prevent infinite mining
+  - **Neither**: Error — must specify at least one termination condition
+- **Best-effort return**: The response always includes the best event found, plus metadata (`achieved_difficulty`, `target_difficulty`, `target_reached`, `elapsed_sec`, `attempts`)
+- **Threading**: Spawn a detached pthread for mining. Server stays responsive. Mining thread writes result to client socket when done.
+- **Key source**: Uses the role's derived private key from `key_store` (same as `sign_event`)
+
+## Why Our Own Mining Loop (Not `nostr_add_proof_of_work()`)
+
+The existing [`nostr_add_proof_of_work()`](resources/nostr_core_lib/nostr_core/nip013.c:121) has two problems for the best-effort model:
+
+1. **Discards work on failure**: It returns `NOSTR_ERROR_CRYPTO_FAILED` if `max_attempts` is exceeded without reaching the target. The best nonce found is lost.
+2. **No time-based termination**: It uses `max_attempts` (a count), not a time deadline. For a "mine for 30 seconds" model, we need time-based termination.
+
+Instead, `miner.c` implements its own mining loop that:
+- Iterates nonces across multiple threads
+- Uses [`nostr_create_and_sign_event()`](resources/nostr_core_lib/nostr_core/nip001.h:1) from nip001 to sign each attempt
+- Uses [`nostr_calculate_pow_difficulty()`](resources/nostr_core_lib/nostr_core/nip013.h:42) from nip013 to check difficulty
+- Tracks the best event (highest difficulty) across all threads
+- Stops when target reached OR timeout
+- Returns the best event with metadata
+
+This reuses the library's crypto/JSON primitives without modifying the shared library.
+
+## Request/Response Format
+
+### Request
+```json
+{
+  "id": "req-1",
+  "method": "mine_event",
+  "params": [
+    "{\"kind\":1,\"content\":\"Hello Nostr!\",\"tags\":[],\"created_at\":1723666800}",
+    {
+      "difficulty": 20,
+      "threads": 4,
+      "timeout_sec": 30,
+      "role": "main"
+    }
+  ]
+}
+```
+
+- `difficulty` (optional): Target leading zero bits. If reached, mining stops early. If not specified, mining runs until timeout.
+- `threads` (optional, default: 1): Number of mining threads.
+- `timeout_sec` (optional): How long to mine in seconds. If not specified, mining runs until target difficulty is reached (with a safety max of 10 minutes).
+- **At least one of `difficulty` or `timeout_sec` must be specified.** If neither is provided, returns error `1007` (`mining_failed` / `no_termination_condition`).
+- **If only `difficulty` is specified**: A safety max timeout of 600 seconds (10 min) is applied to prevent infinite mining.
+- **If only `timeout_sec` is specified**: Mining runs the full duration and returns the best result found.
+- **If both are specified**: Mining stops when either condition is met (target reached OR timeout elapsed).
+
+### Success Response (best-effort, always returned if mining ran)
+```json
+{
+  "id": "req-1",
+  "result": {
+    "event": "{\"kind\":1,\"content\":\"Hello Nostr!\",\"pubkey\":\"...\",\"id\":\"00000...\",\"sig\":\"...\",\"tags\":[[\"nonce\",\"12345\",\"20\"]],\"created_at\":1755197090}",
+    "achieved_difficulty": 18,
+    "target_difficulty": 20,
+    "target_reached": false,
+    "elapsed_sec": 30,
+    "attempts": 4523456
+  }
+}
+```
+
+The `result` is now a JSON **object** (not a string like other verbs) containing the signed event plus mining metadata. The `event` field within it is the signed event JSON string. This is a departure from the other verbs that return a plain string result, but the metadata is essential for the client to know whether the target was met.
+
+### Error Responses
+- `1007` - `mining_failed` — internal error (invalid event, bad params, crypto failure)
+- `1008` - `mining_busy` — another mining operation is already running (optional: reject or queue)
+- Existing error codes (1001-1006, -326xx) apply as usual for policy/selector/enforcement errors
+
+Note: Timeout is NOT an error — it's the normal termination condition. The best result is always returned.
+
+## Architecture Diagram
+
+```mermaid
+flowchart TD
+    Client -->|JSON-RPC mine_event| ServerHandleOne
+    ServerHandleOne -->|policy_check and enforce_verb_role| PolicyEnforcement
+    PolicyEnforcement -->|ALLOWED| SpawnDetachedThread
+    ServerHandleOne -->|returns immediately| ServerLoop
+    SpawnDetachedThread --> MinerCoordinator
+    MinerCoordinator -->|spawn N worker threads| Worker1
+    MinerCoordinator -->|spawn N worker threads| Worker2
+    MinerCoordinator -->|spawn N worker threads| WorkerN
+    Worker1 -->|nostr_create_and_sign_event| NIP001Lib
+    Worker2 -->|nostr_create_and_sign_event| NIP001Lib
+    WorkerN -->|nostr_create_and_sign_event| NIP001Lib
+    NIP001Lib -->|signed event with nonce| CalcDifficulty
+    CalcDifficulty -->|nostr_calculate_pow_difficulty| NIP013Lib
+    NIP013Lib -->|difficulty bits| TrackBest
+    TrackBest -->|mutex protected| BestEvent
+    MinerCoordinator -->|timeout or target reached| JoinThreads
+    JoinThreads -->|best event + metadata| BuildResponse
+    BuildResponse -->|transport_send_framed| Client
+```
+
+## Implementation Steps
+
+### Step 1: Add nip013 to nostr_core_lib build
+
+The Makefile's `lib` target runs:
+```
+cd resources/nostr_core_lib && ./build.sh --nips=1,4,6,19,44
+```
+Add `13` to the `--nips` flag so nip013.c is compiled into the static library.
+
+**Files to modify:**
+- [`Makefile`](Makefile:54) — change `--nips=1,4,6,19,44` to `--nips=1,4,6,13,19,44`
+
+### Step 2: Add VERB_MINE_EVENT to enforcement.c
+
+Add `mine_event` to the known nostr verbs so it passes enforcement.
+
+**Files to modify:**
+- [`src/enforcement.c`](src/enforcement.c:200) — add `#define VERB_MINE_EVENT "mine_event"` and add it to [`is_nostr_verb()`](src/enforcement.c:453)
+- [`src/dispatcher.c`](src/dispatcher.c:200) — add the same `#define VERB_MINE_EVENT "mine_event"` (the headerless decls pattern means defines are repeated per-file)
+
+### Step 3: Create src/miner.c — Multithreaded Best-Effort Mining Coordinator
+
+This is the core new file. It implements a server-safe, best-effort mining loop.
+
+**Key design:**
+- No global variables (all state in context structs)
+- No `exit()` calls (return result codes)
+- No signal handlers (server handles signals)
+- Time-based termination (not attempt-count-based)
+- Tracks best event across all threads
+- Returns best event + metadata regardless of whether target was reached
+
+**Key structures:**
+```c
+typedef struct {
+    cJSON *best_event;           /* best event found so far (mutex-protected) */
+    int best_difficulty;         /* difficulty of best_event */
+    uint64_t total_attempts;     /* total attempts across all threads */
+    int target_difficulty;       /* 0 = no target, mine full timeout */
+    int target_reached;          /* 1 if target was reached */
+    pthread_mutex_t mutex;       /* protects best_event, best_difficulty, total_attempts */
+    volatile int stop;           /* set by coordinator when target reached or timeout */
+} mine_shared_state_t;
+
+typedef struct {
+    mine_shared_state_t *shared;
+    cJSON *event_template;       /* this thread's copy of the event */
+    unsigned char private_key[32];
+    int thread_id;
+    uint64_t nonce_start;        /* starting nonce for this thread (thread_id * stride) */
+    uint64_t nonce_stride;       /* increment per iteration to avoid overlap */
+    time_t deadline;             /* absolute time to stop */
+    uint64_t attempts;           /* this thread's attempt count */
+} miner_worker_ctx_t;
+
+typedef struct {
+    cJSON *best_event;           /* caller frees */
+    int achieved_difficulty;
+    int target_difficulty;
+    int target_reached;
+    int elapsed_sec;
+    uint64_t total_attempts;
+} mine_result_t;
+```
+
+**Main function:**
+```c
+/* Returns 0 on success (result populated with best event found), -1 on error */
+int miner_run(cJSON *event, const unsigned char *private_key,
+              int target_difficulty, int thread_count, int timeout_sec,
+              mine_result_t *result);
+```
+
+**Mining loop (per thread):**
+```c
+while (!shared->stop && time(NULL) < deadline) {
+    /* Build event with current nonce */
+    cJSON *working_tags = cJSON_Duplicate(original_tags, 1);
+    update_nonce_tag(working_tags, nonce, target_difficulty);
+    
+    cJSON *signed_event = nostr_create_and_sign_event(kind, content, working_tags,
+                                                       private_key, timestamp);
+    cJSON_Delete(working_tags);
+    
+    /* Check difficulty */
+    const char *id = cJSON_GetStringValue(cJSON_GetObjectItem(signed_event, "id"));
+    int difficulty = nostr_calculate_pow_difficulty(id);
+    
+    /* Track best under mutex */
+    pthread_mutex_lock(&shared->mutex);
+    shared->total_attempts++;
+    if (difficulty > shared->best_difficulty) {
+        if (shared->best_event) cJSON_Delete(shared->best_event);
+        shared->best_event = cJSON_Duplicate(signed_event, 1);
+        shared->best_difficulty = difficulty;
+    }
+    if (target_difficulty > 0 && difficulty >= target_difficulty) {
+        shared->target_reached = 1;
+        shared->stop = 1;
+    }
+    pthread_mutex_unlock(&shared->mutex);
+    
+    cJSON_Delete(signed_event);
+    nonce += nonce_stride;
+    attempts++;
+}
+```
+
+**Files to create:**
+- `src/miner.c` — mining coordinator (~250 lines)
+
+### Step 4: Add crypto_mine_event() to key_store.c
+
+Add a function that:
+1. Parses the event JSON
+2. Gets the role's private key from key_store
+3. Calls `miner_run()` from miner.c
+4. Builds the response JSON object (event string + metadata)
+5. Zeroizes the private key copy
+6. Returns the response JSON string (caller frees)
+
+**Signature:**
+```c
+/* Returns newly-allocated JSON string with result object, or NULL on error.
+ * Caller frees. */
+char *crypto_mine_event(const key_store_t *store, int role_index,
+                        const char *event_json, int difficulty,
+                        int threads, int timeout_sec);
+```
+
+**Response building:**
+```c
+cJSON *result_obj = cJSON_CreateObject();
+cJSON *event_item = cJSON_CreateString(signed_event_json);
+cJSON_AddItemToObject(result_obj, "event", event_item);
+cJSON_AddNumberToObject(result_obj, "achieved_difficulty", result.achieved_difficulty);
+cJSON_AddNumberToObject(result_obj, "target_difficulty", result.target_difficulty);
+cJSON_AddBoolToObject(result_obj, "target_reached", result.target_reached);
+cJSON_AddNumberToObject(result_obj, "elapsed_sec", result.elapsed_sec);
+cJSON_AddNumberToObject(result_obj, "attempts", (double)result.total_attempts);
+char *out = cJSON_PrintUnformatted(result_obj);
+cJSON_Delete(result_obj);
+return out;
+```
+
+**Files to modify:**
+- [`src/key_store.c`](src/key_store.c:456) — add `#include <nostr_core/nip013.h>`, add `crypto_mine_event()` function, add forward declaration in the headerless decls section
+
+### Step 5: Update Makefile
+
+Add `miner.c` to SOURCES. pthread is already linked (`-lpthread` in LDFLAGS).
+
+**Files to modify:**
+- [`Makefile`](Makefile:13) — add `$(SRC_DIR)/miner.c \` to SOURCES list
+
+### Step 6: Add dispatcher handler for mine_event
+
+In [`dispatcher_handle_request()`](src/dispatcher.c:545), add a branch for `VERB_MINE_EVENT` that:
+1. Extracts `event_json` from params[0]
+2. Extracts `difficulty`, `threads`, `timeout_sec` from the options object (params[last])
+3. Validates: at least one of `difficulty` or `timeout_sec` must be specified (else error `1007`); `threads` defaults to 1 (max 32); if only `difficulty` is set, safety timeout of 600 sec is applied
+4. Calls `crypto_mine_event()`
+5. Returns the result
+
+**Files to modify:**
+- [`src/dispatcher.c`](src/dispatcher.c:675) — add `else if (strcmp(method, VERB_MINE_EVENT) == 0)` branch after the `VERB_SIGN_EVENT` branch
+
+### Step 7: Modify server.c for async mining
+
+The current [`server_handle_one()`](src/server.c:1453) is synchronous. For `mine_event`, we need to:
+
+1. Detect `mine_event` method after policy check passes
+2. Spawn a detached thread that:
+   - Calls `dispatcher_handle_request()` (which calls `crypto_mine_event()`)
+   - Sends the response via `transport_send_framed()` on the client_fd
+   - Closes the client_fd
+3. Return immediately from `server_handle_one()` without closing the fd (the thread owns it now)
+
+**Thread function:**
+```c
+typedef struct {
+    int client_fd;
+    dispatcher_ctx_t *dispatcher;
+    char *request;
+} mine_thread_arg_t;
+
+static void *mine_event_thread(void *arg) {
+    mine_thread_arg_t *a = (mine_thread_arg_t *)arg;
+    char *response = dispatcher_handle_request(a->dispatcher, a->request);
+    if (response != NULL) {
+        (void)transport_send_framed(a->client_fd, response);
+        free(response);
+    }
+    free(a->request);
+    close(a->client_fd);
+    free(a);
+    return NULL;
+}
+```
+
+**In server_handle_one**, after `pchk == POLICY_ALLOW` and before calling `dispatcher_handle_request()`:
+```c
+if (pchk == POLICY_ALLOW && strcmp(method, "mine_event") == 0) {
+    pthread_t tid;
+    mine_thread_arg_t *arg = malloc(sizeof(*arg));
+    if (arg == NULL) {
+        /* fall through to error path */
+    } else {
+        arg->client_fd = client_fd;
+        arg->dispatcher = ctx->dispatcher;
+        arg->request = request;  /* transfer ownership */
+        request = NULL;  /* prevent free in cleanup */
+        if (pthread_create(&tid, NULL, mine_event_thread, arg) == 0) {
+            pthread_detach(tid);
+            /* Skip synchronous response path — thread owns fd and request */
+            /* Log activity and return without closing fd */
+            verdict = "ALLOWED";
+            source_label = "async-mine";
+            /* ... log activity ... */
+            return 1;
+        }
+        /* pthread_create failed — fall through to error path */
+        free(arg->request);
+        free(arg);
+    }
+}
+```
+
+**Files to modify:**
+- [`src/server.c`](src/server.c:1755) — add mine_event async path before the synchronous `dispatcher_handle_request()` call
+
+### Step 8: Add client demos
+
+Add `mine_event` examples to the existing demo files.
+
+**Files to modify:**
+- [`client/demo_javascript.js`](client/demo_javascript.js:1) — add mine_event example
+- [`client/demo_python.py`](client/demo_python.py:1) — add mine_event example
+- [`client/demo_c99.c`](client/demo_c99.c:1) — add mine_event example
+
+### Step 9: Add tests
+
+Create a test that:
+1. Starts nsigner with a test mnemonic
+2. Sends a `mine_event` request with low difficulty (e.g., 2) and short timeout (e.g., 5 sec)
+3. Verifies the response contains a signed event with a nonce tag
+4. Verifies the `achieved_difficulty` >= 2 and `target_reached` is true
+5. Sends a `mine_event` request with high difficulty (e.g., 30) and short timeout (e.g., 3 sec)
+6. Verifies the response contains a signed event, `target_reached` is false, and `achieved_difficulty` < 30
+
+**Files to create:**
+- `tests/test_mine_event.c`
+
+**Files to modify:**
+- [`Makefile`](Makefile:37) — add `TEST_MINE_EVENT_TARGET` and `test-mine-event` target
+
+### Step 10: Update documentation
+
+**Files to modify:**
+- [`README.md`](README.md:1) — add `mine_event` to the verbs table with params description
+- [`client/README.md`](client/README.md:1) — add mine_event usage example
+
+## Security Considerations
+
+1. **Private key never leaves key_store**: The mining thread receives a copy of the 32-byte private key, which is zeroized after use (following the pattern in [`crypto_sign_event()`](src/key_store.c:456))
+2. **Policy enforcement applies**: `mine_event` goes through the same `policy_check()` and `enforce_verb_role()` as all other verbs
+3. **Thread safety**: 
+   - Each mining thread works on its own cJSON copies
+   - The shared state (best_event, best_difficulty, total_attempts) is protected by a mutex
+   - secp256k1 context is thread-safe for signing
+4. **Resource limits**: 
+   - Max threads capped at 32 to prevent resource exhaustion
+   - `timeout_sec` is required (must be > 0) to prevent infinite mining
+   - Optional: limit to 1 concurrent mining operation (reject with `mining_busy` if already running)
+5. **Client fd ownership**: The detached thread owns the client_fd and is responsible for closing it. The main server loop must not close it.
+
+## Concurrency Considerations
+
+- Each mining thread uses a unique nonce stride (thread_id) to avoid duplicate work
+- cJSON operations are NOT thread-safe across different cJSON objects, but each thread works on its own copies
+- The result mutex protects only the shared best-event tracking
+- `nostr_create_and_sign_event()` creates a new secp256k1 context per call (or uses a thread-local one) — need to verify this is thread-safe. If not, each thread may need its own context.
+
+## File Summary
+
+| File | Action | Description |
+|------|--------|-------------|
+| `Makefile` | Modify | Add nip013 to --nips, add miner.c to SOURCES, add test target |
+| `src/enforcement.c` | Modify | Add VERB_MINE_EVENT to is_nostr_verb() |
+| `src/dispatcher.c` | Modify | Add VERB_MINE_EVENT define + handler branch |
+| `src/key_store.c` | Modify | Add crypto_mine_event() function + nip013 include |
+| `src/miner.c` | Create | Multithreaded best-effort mining coordinator |
+| `src/server.c` | Modify | Add async mine_event path with detached thread |
+| `tests/test_mine_event.c` | Create | Integration test for mine_event |
+| `client/demo_javascript.js` | Modify | Add mine_event example |
+| `client/demo_python.py` | Modify | Add mine_event example |
+| `client/demo_c99.c` | Modify | Add mine_event example |
+| `README.md` | Modify | Document mine_event verb |
+| `client/README.md` | Modify | Add mine_event usage |

plans/nostr_core_lib_client_updates.md

@@ -0,0 +1,123 @@
+# Plan: nostr_core_lib client updates for new n_signer features
+
+Status: design / ready for review.
+
+Related:
+- [`../nostr_core_lib/nostr_core/nsigner_transport.h`](../../nostr_core_lib/nostr_core/nsigner_transport.h) — transport vtable
+- [`../nostr_core_lib/nostr_core/nsigner_client.h`](../../nostr_core_lib/nostr_core/nsigner_client.h) — low-level client
+- [`../nostr_core_lib/nostr_core/nostr_signer.h`](../../nostr_core_lib/nostr_core/nostr_signer.h) — high-level signer
+- [`../nostr_core_lib/nostr_core/nostr_signer.c`](../../nostr_core_lib/nostr_core/nostr_signer.c) — `signer_remote_params_with_selector`
+- [`plans/qrexec_persistent_bridge.md`](qrexec_persistent_bridge.md) — qrexec bridge design
+- [`plans/interactive_transport_selection.md`](interactive_transport_selection.md) — index whitelist
+
+---
+
+## 1. Gaps identified
+
+The `nostr_core_lib` client stack was built before the recent n_signer features. Three gaps need filling:
+
+### 1.1 No `nostr_index` selector in the high-level API
+
+`signer_remote_params_with_selector()` ([`nostr_signer.c:287`](../../nostr_core_lib/nostr_core/nostr_signer.c:287)) only emits `{"role":"..."}`. It does not support `{"nostr_index":N}`, which is n_signer's primary key-selection mechanism for Nostr identities (NIP-06 `m/44'/1237'/N'/0/0`).
+
+The `nostr_signer_nsigner_*` constructors take a `const char* role` parameter. There's no way to say "use nostr_index 3" through the high-level API. Callers who want a specific Nostr identity by index must drop down to the low-level `nsigner_client_call` and build params manually — which is exactly what [`examples/get_pubkey_tcp.c`](../examples/get_pubkey_tcp.c) and [`examples/n_signer_qube_example_fips.js`](../examples/n_signer_qube_example_fips.js) do.
+
+### 1.2 No qrexec transport
+
+`nsigner_transport_open_*` supports unix, tcp, serial, fds — but not qrexec. On Qubes OS, the primary inter-qube path is `qrexec-client-vm <target> qubes.NsignerRpc`, which pipes framed I/O through stdin/stdout of a subprocess. There's no transport that wraps this.
+
+### 1.3 No error code mapping for `index_not_allowed` (2002)
+
+n_signer now returns `{"error":{"code":2002,"message":"index_not_allowed"}}` when the index whitelist denies a request. The client should surface this distinctly from `policy_denied` (2001) so callers can tell "this index isn't whitelisted" vs "this caller isn't approved".
+
+---
+
+## 2. Proposed changes
+
+### 2.1 Add `nostr_index` selector to the high-level API
+
+**Option A (minimal):** Add a new constructor variant that takes `nostr_index` instead of `role`:
+
+```c
+nostr_signer_t* nostr_signer_nsigner_unix_index(const char* socket_name, int nostr_index, int timeout_ms);
+nostr_signer_t* nostr_signer_nsigner_tcp_index(const char* host, int port, int nostr_index, int timeout_ms);
+/* etc. */
+```
+
+**Option B (cleaner):** Replace the `role` string parameter with a selector struct:
+
+```c
+typedef struct {
+    const char* role;       /* NULL = use default */
+    int nostr_index;        /* -1 = not set */
+    const char* role_path;  /* NULL = not set */
+} nsigner_selector_t;
+
+nostr_signer_t* nostr_signer_nsigner_unix(const char* socket_name, const nsigner_selector_t* selector, int timeout_ms);
+```
+
+**Option C (additive, chosen):** Keep existing constructors, add a setter for nostr_index:
+
+```c
+int nostr_signer_nsigner_set_nostr_index(nostr_signer_t* signer, int nostr_index);
+```
+
+This sets the index on the remote backend, and `signer_remote_params_with_selector` emits `{"nostr_index":N}` instead of `{"role":"..."}` when set. Existing callers using `role` are unaffected.
+
+**Decision: Option C** — additive, no API break, smallest change.
+
+### 2.2 Add qrexec transport
+
+New transport constructor:
+
+```c
+nsigner_transport_t* nsigner_transport_open_qrexec(const char* target_qube, const char* service_name, int timeout_ms);
+```
+
+Implementation: `fork()` + `execvp("qrexec-client-vm", [target_qube, service_name])` with `stdin`/`stdout` pipes. The `send_framed`/`recv_framed` vtable methods write/read through the pipes. `reconnect` re-spawns the subprocess (qrexec handles one request per invocation, so reconnect is mandatory before each call — same as the existing per-request reconnect pattern).
+
+The transport is stateless per call: each `reconnect` spawns a fresh `qrexec-client-vm` process, sends one framed request, reads one framed response, and the process exits. This matches the qrexec execution model.
+
+### 2.3 Add `nostr_signer_nsigner_qrexec` high-level constructor
+
+```c
+nostr_signer_t* nostr_signer_nsigner_qrexec(const char* target_qube, const char* service_name, const char* role, int timeout_ms);
+```
+
+Wraps `nsigner_transport_open_qrexec` + `nostr_signer_nsigner_from_transport`. No auth envelope needed — qrexec identity comes from `QREXEC_REMOTE_DOMAIN` on the server side.
+
+### 2.4 Surface `index_not_allowed` error distinctly
+
+Add to `nostr_common.h`:
+
+```c
+#define NOSTR_ERROR_NSIGNER_INDEX_NOT_ALLOWED -2002
+```
+
+In `nsigner_client_call` (or `nostr_signer` remote backend), when the response error code is 2002, map it to `NOSTR_ERROR_NSIGNER_INDEX_NOT_ALLOWED` so callers can distinguish it from generic policy denial.
+
+---
+
+## 3. Implementation checklist
+
+In `nostr_core_lib`:
+
+- [ ] `nsigner_transport.h` / `nsigner_transport.c`: add `nsigner_transport_open_qrexec(target_qube, service_name, timeout_ms)` — fork+exec `qrexec-client-vm`, pipe-based framed I/O, reconnect re-spawns.
+- [ ] `nostr_signer.h` / `nostr_signer.c`: add `nostr_signer_nsigner_qrexec(target_qube, service_name, role, timeout_ms)`.
+- [ ] `nostr_signer.c`: add `nostr_signer_nsigner_set_nostr_index(signer, nostr_index)`; update `signer_remote_params_with_selector` to emit `{"nostr_index":N}` when index is set.
+- [ ] `nostr_common.h`: add `NOSTR_ERROR_NSIGNER_INDEX_NOT_ALLOWED` error code.
+- [ ] `nsigner_client.c`: map error code 2002 to the new constant.
+- [ ] `NSIGNER_INTEGRATION.md`: document the qrexec transport, nostr_index selector, and index_not_allowed error.
+
+In `n_signer` (this repo):
+
+- [ ] Update [`examples/get_pubkey_tcp.c`](../examples/get_pubkey_tcp.c) to optionally use the high-level `nostr_signer` API with `nostr_index` selector (demonstrates the new client API).
+- [ ] Add a C example for the qrexec path using the new `nostr_signer_nsigner_qrexec` constructor.
+
+---
+
+## 4. Open questions
+
+1. **Should the qrexec transport live in `nostr_core_lib` or in a Qubes-specific addon?** The transport is only useful on Qubes OS, but `nostr_core_lib` is meant to be cross-platform. **Decision: put it in `nostr_core_lib` behind `NOSTR_ENABLE_NSIGNER_CLIENT` — it just won't work on non-Qubes hosts (execvp fails). No new feature flag needed.**
+
+2. **Should `nostr_signer_nsigner_set_nostr_index` override `role` or coexist?** n_signer rejects ambiguous selectors (both `role` and `nostr_index` set = `ambiguous_role_selector`). **Decision: setting nostr_index clears role, and vice versa. The setter is exclusive.**

plans/otp_nostr_integration.md

@@ -0,0 +1,340 @@
+# Plan: OTP-encrypted Nostr events via n_signer
+
+## Goal
+
+Store encrypted blobs on Nostr (kind `30078` replaceable parameterized events) that are
+**information-theoretically secure** — unbreakable by any computer, quantum or classical,
+forever — because they are encrypted with a one-time pad (OTP) sourced from the
+[`otp`](../otp) project.
+
+A client program sends plaintext (or a ciphertext) to `n_signer` over its existing
+JSON-RPC transport. `n_signer` performs the OTP XOR against pad material it reads from a
+USB drive, advances the per-pad offset, and returns the ciphertext (or plaintext). The
+caller then wraps the result in a Nostr `30078` event and signs/publishes it via the
+existing `sign_event` verb.
+
+Both output encodings are supported, matching the standalone `otp` tool:
+
+- **ASCII armored** (`-----BEGIN OTP MESSAGE-----` + base64): text-safe, for embedding
+  directly in Nostr event `content` (kind `30078`).
+- **Binary** (`.otp` structured header + raw encrypted bytes): for uploading to Blossom
+  servers as a blob and referencing from a Nostr event by SHA-256 hash. The caller
+  receives the binary blob base64-encoded in the JSON-RPC response and decodes it
+  before uploading.
+
+For testing, pad material can be generated from local entropy (`/dev/urandom` or
+keyboard entropy) using the `otp` tool. The eventual production target is a USB drive
+holding the pad, accessed by `n_signer` at runtime. A future microcontroller hardware
+signer that carries the pad onboard is explicitly out of scope for this plan and is
+tracked separately.
+
+## Design summary
+
+- `n_signer` gains two new verbs: `otp_encrypt` and `otp_decrypt`.
+- Pad material lives on a USB drive (file path supplied at startup). `n_signer` reads
+  only the slice it needs, XORs in `mlock`'d RAM, and writes the new offset back to the
+  pad's `.state` file on the USB drive.
+- The pad is **not** loaded whole into RAM; it is seeked-and-read per request. This
+  preserves the spirit of the zero-filesystem-footprint model (no pad material is ever
+  copied onto the host disk; the only on-disk artifact is the offset counter on the USB
+  drive itself, which is required for multi-device coordination).
+- The encrypted payload is returned in either ASCII-armored or binary `.otp` format,
+  selected per request via an `encoding` option. ASCII armor is base64-safe for JSON
+  and Nostr event `content`; binary `.otp` is for Blossom blob uploads.
+- The caller is responsible for building and publishing the `30078` event; `n_signer`
+  only does the OTP transform and (separately) signs the event when asked.
+
+```mermaid
+flowchart LR
+  Client[Client program] -->|otp_encrypt JSON-RPC| NS[n_signer]
+  NS -->|seek + read slice| USB[USB pad file .pad]
+  NS -->|read/advance offset| State[USB .state file]
+  NS -->|XOR in mlock RAM| CT[Ciphertext blob]
+  NS -->|return ascii-armored| Client
+  Client -->|wrap in 30078 event| Event[Nostr event JSON]
+  Client -->|sign_event| NS
+  NS -->|schnorr sig| Client
+  Client -->|publish| Relay[Nostr relay]
+```
+
+## Architecture decisions
+
+### 1. New verbs, not a new transport
+
+OTP operations are just new verbs on the existing dispatcher
+([`src/dispatcher.c`](src/dispatcher.c:1)). They use the same framed JSON-RPC,
+policy, approval, and enforcement machinery as `sign_event` / `nip44_encrypt`. No new
+transport is needed.
+
+### 2. Pad storage on USB, not in mnemonic RAM
+
+The OTP pad is far too large to live in `mlock`'d RAM (gigabytes) and is not
+mnemonic-derived. It lives on a USB drive mounted at a path `n_signer` is told at
+startup via a new `--otp-pad-dir <path>` flag. `n_signer` opens the pad file
+read-only, seeks to the current offset, reads exactly `chunk_size` bytes (after
+Padmé padding), XORs against the (padded) plaintext in a small `mlock`'d scratch
+buffer, and writes the advanced offset back to `<chksum>.state` on the USB drive.
+
+This is a deliberate, narrow exception to the "zero filesystem footprint" rule: the
+only filesystem artifact `n_signer` touches is the offset counter on the USB drive
+itself, which is mandatory for pad-reuse avoidance across devices. No pad bytes and
+no plaintext ever touch the host disk.
+
+### 2a. Qubes OS USB access strategy
+
+On Qubes, the signer qube must have sole access to the pad-bearing USB drive. The
+chosen strategy is **PCI USB controller passthrough** (Option A): an entire USB
+controller is assigned to the signer qube via `qvm-pci attach`, so dom0, `sys-usb`,
+and every other qube are blind to the pad device. The drive appears as a normal
+`/dev/sd*` inside the signer qube.
+
+Fallback if no spare controller is available: **`qvm-block attach` from `sys-usb`**
+(Option B), accepting that `sys-usb` briefly enumerates the device and block I/O
+transits dom0's blkback (a traffic-analysis concern, not a plaintext-leak concern
+since pad bytes stay encrypted-on-disk).
+
+Code-level guard (Option D): `n_signer` refuses to open `--otp-pad-dir` unless the
+underlying device is a directly-owned PCI device (`/dev/sd*` from a passthrough
+controller) when running under Qubes; blkback devices (`/dev/xvdi`) are rejected
+unless `--otp-allow-blkback` is explicitly passed. This makes "sole access" a
+code-level invariant, not just an operator convention.
+
+Offset writes use atomic write-temp-then-rename so a crash mid-write cannot corrupt
+the `.state` file. The offset is advanced **only after** the XOR succeeds and the
+ciphertext is handed back to the caller.
+
+### 3. Reuse the `otp` project's file formats and padding
+
+- Pad file format: `<chksum>.pad` raw random bytes, with a 32-byte header reserved
+  (matches [`../otp/src/pads.c`](../otp/src/pads.c:1) `offset=32` initial reservation).
+- State file format: `<chksum>.state` containing `offset=<n>\n` (matches
+  [`../otp/src/pads.c:284`](../otp/src/pads.c:284) `read_state_offset`).
+- ASCII armor format: `-----BEGIN OTP MESSAGE-----` with `Pad-ChkSum` and
+  `Pad-Offset` headers (matches [`../otp/src/crypto.c`](../otp/src/crypto.c:1)
+  `parse_ascii_message` / `generate_ascii_armor`).
+- Padding: exponential bucketing + ISO/IEC 9797-1 Method 2 (Padmé) from
+  [`../otp/src/padding.c`](../otp/src/padding.c:1).
+
+This means pads generated by the standalone `otp` CLI are bit-compatible with pads
+consumed by `n_signer`, and ciphertexts produced by either tool are interchangeable.
+
+### 4. Code sharing strategy
+
+Rather than vendoring a copy of the `otp` source into `n_signer`, extract the
+format-critical functions into a small shared static library `libotppad` that both
+projects link against. Candidates to extract:
+
+- `universal_xor_operation` ([`../otp/src/crypto.c:35`](../otp/src/crypto.c:35))
+- `parse_ascii_message` / `generate_ascii_armor`
+- `calculate_chunk_size` / `apply_padme_padding` / `remove_padme_padding`
+  ([`../otp/src/padding.c`](../otp/src/padding.c:1))
+- `read_state_offset` / `write_state_offset`
+  ([`../otp/src/pads.c:284`](../otp/src/pads.c:284))
+- `calculate_checksum` (pad identification)
+
+`n_signer` then only needs to implement: USB pad directory config, the two new
+dispatcher verbs, the seek-read-XOR-write-offset loop, and approval/policy wiring.
+
+### 5. Nostr event shape (kind 30078)
+
+The caller builds the event; `n_signer` does not. Two payload patterns:
+
+**A. ASCII armor in event content** (text-safe, self-contained):
+
+```json
+{
+  "kind": 30078,
+  "content": "-----BEGIN OTP MESSAGE-----\nVersion: v0.3.53\nPad-ChkSum: <64hex>\nPad-Offset: <n>\n\n<base64>\n-----END OTP MESSAGE-----",
+  "tags": [
+    ["d", "<caller-chosen-d-tag>"],
+    ["otp-pad", "<16-char chksum prefix>"],
+    ["otp-version", "v0.3.53"],
+    ["otp-encoding", "ascii"]
+  ],
+  ...
+}
+```
+
+**B. Binary `.otp` uploaded to Blossom, referenced by hash** (for binaries/large blobs):
+
+```json
+{
+  "kind": 30078,
+  "content": "",
+  "tags": [
+    ["d", "<caller-chosen-d-tag>"],
+    ["otp-pad", "<16-char chksum prefix>"],
+    ["otp-version", "v0.3.53"],
+    ["otp-encoding", "binary"],
+    ["blob", "<sha256-hex>", "<mimetype>", "<size-bytes>"],
+    ["url", "<blossom-url>"]
+  ],
+  ...
+}
+```
+
+In both cases the `Pad-Offset` (in the ASCII armor header, or in the binary `.otp`
+file header) is what a decrypting device uses to seek into its copy of the same pad.
+The `otp-pad` tag lets a reader find the right pad without parsing the payload first.
+The `otp-encoding` tag tells the reader whether to look in `content` or follow the
+`blob`/`url` tags to Blossom.
+
+### 6. Multi-device offset coordination (deferred)
+
+Out of scope for v1. The `.state` file on the device's USB drive is the local source
+of truth for how far that device has consumed the pad, and the `Pad-Offset` header
+in each ciphertext's ASCII armor / binary header records which slice was used. That
+is sufficient for single-device operation.
+
+If multi-device pad sharing is added later (two devices holding copies of the same
+`.pad`), a dedicated signed coordination event would be needed so devices never
+reuse a slice. That event does not have to be kind `30078` and is not designed here.
+Note: kind `30078` is a Nostr application-data convention, not part of the OTP spec —
+the `otp` project has no Nostr code today.
+
+## Phased implementation
+
+### Phase 0 — Test pad on the USB drive ✅ Done
+
+- [x] Created `pads/` directory on the mounted USB drive.
+- [x] Generated a 1 MB test pad from `/dev/urandom` with a 32-byte reserved header,
+      using [`tools/make_test_pad.c`](tools/make_test_pad.c:1).
+- [x] Computed the pad's 256-bit XOR checksum (matching the `otp` project's
+      [`../otp/src/crypto.c:242`](../otp/src/crypto.c:242) `calculate_checksum`
+      algorithm) and named the pad file by that checksum.
+- [x] Wrote the initial `.state` file (`offset=32\n`).
+- [x] Verified the checksum matches the filename via an independent re-computation.
+
+**Actual test pad on this qube:**
+
+| Field | Value |
+|---|---|
+| USB drive | SanDisk 3.2 Gen1, 466 GB, `/dev/sda1` |
+| Mount point | `/media/user/Music` (FAT32, label "Music") |
+| Pad directory | `/media/user/Music/pads` |
+| Pad file | `333e9902db839d9d7f1f6aaa30f392a77c9abd011dd6274d9d3cf167361a789e.pad` |
+| State file | `333e9902db839d9d7f1f6aaa30f392a77c9abd011dd6274d9d3cf167361a789e.state` |
+| Size | 1,048,576 bytes (1 MB) |
+| Chksum prefix | `333e9902db839d9d` |
+| Initial offset | 32 (header reserved) |
+
+Note: the drive is currently mounted at `/media/user/Music` (its FAT32 label is
+"Music"), not at `/media/user/USBDISK`. For `n_signer` testing, pass
+`--otp-pad-dir /media/user/Music/pads`. This pad is for local-entropy testing only;
+production pads will be generated with the `otp` CLI (keyboard/TRNG entropy) or a
+future hardware signer.
+
+### Phase 1 — Shared `libotppad` extraction
+
+- [ ] Create `libotppad/` directory with the format-critical functions extracted from
+      [`../otp/src/crypto.c`](../otp/src/crypto.c:1), [`../otp/src/padding.c`](../otp/src/padding.c:1),
+      and [`../otp/src/pads.c`](../otp/src/pads.c:1).
+- [ ] Add a `libotppad.h` public header declaring: `universal_xor_operation`,
+      `parse_ascii_message`, `generate_ascii_armor`, `calculate_chunk_size`,
+      `apply_padme_padding`, `remove_padme_padding`, `read_state_offset`,
+      `write_state_offset`, `calculate_checksum`.
+- [ ] Refactor the `otp` project to link against `libotppad` instead of its own copies.
+- [ ] Add unit tests for `libotppad` (round-trip encrypt/decrypt, padding edge cases,
+      state file read/write).
+
+### Phase 2 — `n_signer` USB pad directory support
+
+- [ ] Add `--otp-pad-dir <path>` CLI flag to [`src/main.c`](src/main.c:1); store the
+      path in a new `otp_pad_state_t` alongside the existing mnemonic/role state.
+- [ ] Add a `--otp-pad <chksum-or-prefix>` flag (or interactive selector) to pick
+      **the single pad** that is active for this session. One pad per session — the
+      pad is bound at startup and cannot be switched without restarting `n_signer`.
+- [ ] Implement `otp_pad_open(chksum)` / `otp_pad_read_slice(offset, len)` /
+      `otp_pad_advance_offset(delta)` helpers in a new `src/otp_pad.c`.
+- [ ] Validate the pad's checksum matches the requested chksum before first use.
+- [ ] Refuse to operate if the pad directory is on the same filesystem as `/` (require
+      it to be a removable mount — best-effort check via `statvfs`).
+
+### Phase 3 — `otp_encrypt` / `otp_decrypt` verbs
+
+- [ ] Add `VERB_OTP_ENCRYPT "otp_encrypt"` and `VERB_OTP_DECRYPT "otp_decrypt"` to
+      [`src/dispatcher.c`](src/dispatcher.c:1).
+- [ ] Request shapes (plaintext is base64 in the JSON param for both text and
+      binary; the pad is the one bound at startup, so no `pad` field is needed):
+  ```json
+  { "id": "1", "method": "otp_encrypt",
+    "params": [ "<plaintext-base64>", { "encoding": "ascii|binary" } ] }
+  ```
+  ```json
+  { "id": "2", "method": "otp_decrypt",
+    "params": [ "<ciphertext-ascii-armor-or-base64-otp-blob>", { "encoding": "ascii|binary" } ] }
+  ```
+- [ ] `otp_encrypt` flow: padmé-pad plaintext → seek to offset → read slice → XOR in
+      `mlock`'d scratch → advance offset → return ciphertext in requested encoding
+      (`ascii` → ASCII-armored string, `binary` → base64-encoded `.otp` blob in the
+      JSON result).
+- [ ] `otp_decrypt` flow: accept either ASCII armor or base64-encoded binary `.otp`
+      blob → parse header → seek to `Pad-Offset` → read slice → XOR in `mlock`'d
+      scratch → strip padding → return plaintext (in requested encoding).
+- [ ] Add an `encoding` option to both verbs: `"encoding": "ascii"` (default) or
+      `"encoding": "binary"`. For `otp_encrypt`, controls output format. For
+      `otp_decrypt`, tells the signer what format the input is in (auto-detection by
+      magic bytes `OTP\0` is a fallback).
+- [ ] Wire both verbs into the policy/enforcement table
+      ([`src/policy.c`](src/policy.c:1), [`src/enforcement.c`](src/enforcement.c:1))
+      with **per-session grant** approval: the first `otp_encrypt` / `otp_decrypt`
+      call for the session prompts the user; once granted, subsequent calls on the
+      same pad in the same session do not re-prompt. This matches the `[a] always
+      allow this session` hotkey behavior already in [`README.md`](README.md:1).
+- [ ] Add approval-prompt display fields: pad chksum prefix, offset before/after,
+      plaintext length bucket.
+
+### Phase 4 — Local-entropy test path
+
+- [ ] Document the test workflow: generate a small pad with the `otp` CLI
+      (`./otp generate 1MB`) into a directory, point `n_signer` at it with
+      `--otp-pad-dir`, run `otp_encrypt` round-trips from a client.
+- [ ] Add an integration test in [`tests/test_integration.c`](tests/test_integration.c:1)
+      that: starts `n_signer` with a temp pad dir, calls `otp_encrypt` then
+      `otp_decrypt`, asserts round-trip equality, and asserts the offset advanced by
+      the padded chunk size.
+- [ ] Add a test that confirms a ciphertext produced by `n_signer` can be decrypted by
+      the standalone `otp` CLI (cross-compatibility).
+
+### Phase 5 — Nostr 30078 client example
+
+- [ ] Add `examples/otp_nostr_30078.c` showing: call `otp_encrypt` → build a kind 30078
+      event with the ASCII armor as `content` → call `sign_event` → print the signed
+      event for publishing.
+- [ ] Add a matching `examples/otp_nostr_30078_decrypt.c` showing: fetch a 30078 event
+      → call `otp_decrypt` with its `content` → print recovered plaintext.
+- [ ] Document the workflow in [`documents/`](documents/) and link from
+      [`README.md`](README.md:1).
+
+### Phase 6 (deferred) — USB-bound pad hardening
+
+- [ ] Detect removable-mount requirement more strictly (udev properties).
+- [ ] Optional: read-only mount enforcement, pad integrity re-check on each request.
+- [ ] Optional: per-pad `mlock`'d offset cache so a crash mid-request does not corrupt
+      the `.state` file (write-offset-after-success-only is already the plan).
+
+### Phase 7 (explicitly deferred) — Microcontroller hardware signer with onboard pad
+
+Tracked separately. When it lands, the `--otp-pad-dir` path is replaced by a transport
+call (serial/WebUSB) to a pad-serving firmware, and the verbs stay identical.
+
+## Decisions
+
+1. **Plaintext encoding in `otp_encrypt` params.** Accept base64 in the JSON param
+   for both text and binary plaintext; the signer decodes it. Output encoding is the
+   `ascii` vs `binary` option described above.
+2. **One pad per session.** The pad is bound at `n_signer` startup via
+   `--otp-pad-dir` + `--otp-pad` and cannot be switched without restarting the
+   signer. Simpler and safer for v1.
+3. **No pad-heartbeat event in v1.** The `.state` file on the USB drive is the local
+   source of truth; the `Pad-Offset` header in each ciphertext records the slice
+   used. Multi-device pad sharing and any coordination event are deferred. (Kind
+   `30078` is a Nostr application-data convention, not part of the OTP spec.)
+4. **Per-session grant approval.** The first `otp_encrypt` / `otp_decrypt` call in a
+   session prompts the user; once granted, subsequent calls on the same pad do not
+   re-prompt. Matches the existing `[a] always allow this session` behavior.
+5. **Qubes USB strategy.** PCI USB controller passthrough (Option A) is the target;
+   `qvm-block` from `sys-usb` (Option B) is the fallback. For development/testing,
+   the USB drive is already accessible in this qube at `/media/user/Music` (see
+   Phase 0). Code-level guard (Option D) rejects blkback devices unless
+   `--otp-allow-blkback` is passed.

plans/post_quantum_crypto.md

@@ -0,0 +1,567 @@
+# Plan: Post-Quantum Cryptography + Standard ECC Expansion for n_signer
+
+## 1. Goal
+
+Expand n_signer's crypto palette from the current single algorithm (secp256k1 for Nostr) to a complete offering:
+
+**Standard ECC (classical):**
+- `ed25519` — SSH signing keys (works with current OpenSSH), general-purpose signatures
+- `x25519` — key agreement (age encryption, WireGuard-style identities, SSH KEX classical leg)
+
+**Post-quantum (NIST FIPS standardized):**
+- `ML-DSA-65` (FIPS 204, lattice-based signatures) — post-quantum digital signatures
+- `SLH-DSA-128s` (FIPS 205, hash-based signatures) — post-quantum signatures with minimal trust assumptions
+- `ML-KEM-768` (FIPS 203, lattice-based KEM) — post-quantum key encapsulation for encryption
+
+All six algorithms are always compiled in on all targets (host x86_64 static binary and ESP32 firmware). Size is acceptable on both; signing speed for SLH-DSA-128s on ESP32 may be slow (5-30s) but the user accepts this and will choose whether to use it per-role.
+
+## 2. Background and context
+
+### 2.1 Current state
+
+n_signer models three curves in [`role_curve_t`](src/role_table.c:89) (`secp256k1`, `ed25519`, `x25519`) and five purposes in [`role_purpose_t`](src/role_table.c:79) (`nostr`, `bitcoin`, `ssh`, `age`, `fips`). However, only `PURPOSE_NOSTR + CURVE_SECP256K1` is actually implemented:
+
+- [`crypto_derive_all`](src/key_store.c:484) and [`crypto_derive_one`](src/key_store.c:548) skip any role that isn't `PURPOSE_NOSTR + CURVE_SECP256K1 + SELECTOR_NOSTR_INDEX`.
+- [`enforce_verb_role`](src/enforcement.c:468) only allows nostr verbs on `PURPOSE_NOSTR + CURVE_SECP256K1`; everything else returns `ENFORCE_ERR_UNKNOWN_VERB` or a mismatch.
+- [`derived_key_t`](src/key_store.c:303) uses fixed 32-byte arrays for private/public keys — insufficient for PQ keys (ML-DSA-65 priv is 4032 bytes, pub 1952 bytes).
+
+### 2.2 PQ key derivation from mnemonic
+
+PQ private keys are not scalars — they are complex mathematical structures (polynomial matrices for lattice schemes, hypertree seeds for hash-based schemes). You cannot use a 32-byte BIP-32 output directly as a PQ private key.
+
+However, all three PQ algorithms internally use a seed to generate the full key pair via keygen. The approach:
+
+1. Derive a 32-byte seed from the mnemonic using BIP-32/HMAC (same as secp256k1 today, using a PQ-specific derivation path)
+2. Feed that seed into a deterministic PRNG (SHA-256-DRBG or SHAKE-256)
+3. Replace PQClean's `randombytes()` callback with this PRNG so keygen is deterministic
+4. The algorithm expands the seed into the full key pair
+
+This gives **deterministic, mnemonic-recoverable PQ keys** — same mnemonic, same role, same key pair every time. The crash-equals-wipe model from [`README.md`](README.md) is preserved because we re-derive from the mnemonic on every startup. No persistence needed.
+
+This is the same technique used by PQM4 (the MCU post-quantum benchmark project) for deterministic test vectors.
+
+### 2.3 SSH post-quantum landscape
+
+Per OpenSSH's PQ page (openssh.com/pq.html):
+- **KEX (key agreement)**: PQ supported since OpenSSH 9.0, default since 10.0 (`mlkem768x25519-sha256`). This is session encryption, handled by the SSH protocol — n_signer is not involved.
+- **Signature/authentication keys**: "OpenSSH will add support for post-quantum signature algorithms in the future." Not yet implemented. SSH signing keys are still classical (ed25519, RSA, ECDSA).
+
+Implication: ed25519 is still required for SSH signing keys today. ML-DSA-65 is forward-looking — we build the primitive before the ecosystem supports it. When OpenSSH adds PQ signing keys, n_signer will already have ML-DSA-65 ready.
+
+### 2.4 Library choice: PQClean
+
+**PQClean** (public domain / CC0) is the reference implementation source for all three algorithms. Reasons:
+
+- **ESP32-compatible**: Self-contained C, no build system dependency, proven on Cortex-M4 via PQM4. No CMake, no provider loading, no OpenSSL 3.x requirement.
+- **Minimal footprint**: Vendor only the three algorithm folders. No infrastructure code from liboqs.
+- **Public domain**: No license complexity for a security-critical project.
+- **`randombytes()` hook**: Each algorithm calls a `randombytes()` function that we can replace with our mnemonic-seeded PRNG for deterministic keygen.
+
+liboqs was considered but rejected: designed for servers, CMake-heavy, pulls in infrastructure code not needed on MCU, no MCU deployments. oqs-provider was rejected: requires OpenSSL 3.x provider loading, not viable on ESP32.
+
+For ed25519 and x25519: use existing OpenSSL (already linked) or libsecp256k1's sibling curve25519 code. OpenSSL's EVP_PKEY API already supports both. On ESP32, use the ESP-IDF mbedtls component which has ed25519/x25519 support.
+
+## 3. Design
+
+### 3.1 Algorithm registry
+
+Introduce a new `src/pq_crypto.c` / `pq_crypto.h` (headerless-decls style matching the project convention) that provides a unified interface over all six algorithms. The core abstraction:
+
+```c
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,   /* existing, Nostr */
+    CRYPTO_ALG_ED25519,         /* new, SSH signatures */
+    CRYPTO_ALG_X25519,          /* new, key agreement */
+    CRYPTO_ALG_ML_DSA_65,       /* new, PQ signatures */
+    CRYPTO_ALG_SLH_DSA_128S,    /* new, PQ signatures */
+    CRYPTO_ALG_ML_KEM_768,      /* new, PQ KEM */
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;        /* 0 for KEM */
+    size_t ciphertext_len; /* 0 for signatures */
+    size_t shared_secret_len; /* 0 for signatures */
+} crypto_alg_sizes_t;
+
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+
+/* Map role_curve_t + role_purpose_t to crypto_alg_t */
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+```
+
+### 3.2 Variable-length key storage
+
+Replace the fixed 32-byte [`derived_key_t`](src/key_store.c:303) with a variable-length design:
+
+```c
+typedef struct {
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char key_id[128];           /* human-readable key identifier (bech32/hex/algorithm-specific) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
+    int valid;
+} derived_key_t;
+```
+
+The `secure_buf_t` already supports variable sizes via [`secure_buf_alloc`](src/secure_mem.c). The change is allocating different sizes per role based on the algorithm.
+
+### 3.3 Derivation paths
+
+Each algorithm gets a distinct BIP-32 derivation path from the mnemonic. All paths follow the standard 5-level BIP-44 structure for consistency: `m/purpose'/coin_type'/account'/change/index`. This ensures no two algorithms derive from the same path (avoiding key reuse across algorithms) and maintains compatibility with standard HD wallet tooling.
+
+| Algorithm | Purpose | Derivation path | Notes |
+|---|---|---|---|
+| secp256k1 | nostr | `m/44'/1237'/<n>'/0/0` (existing) | NIP-06, unchanged |
+| secp256k1 | bitcoin | `m/44'/0'/<account>'/0/0` etc. | BIP-44, future |
+| ed25519 | ssh | `m/44'/102001'/<n>'/0'/0'` | SLIP-0010 ed25519 (all hardened) |
+| x25519 | age | `m/44'/102002'/<n>'/0'/0'` | SLIP-0010 x25519 (all hardened) |
+| ML-DSA-65 | pq-sig | `m/44'/102003'/<n>'/0'/0'` → seed → PQClean keygen | PQ-SIG coin type |
+| SLH-DSA-128s | pq-sig | `m/44'/102004'/<n>'/0'/0'` → seed → PQClean keygen | PQ-HASH-SIG coin type |
+| ML-KEM-768 | pq-kem | `m/44'/102005'/<n>'/0'/0'` → seed → PQClean keygen | PQ-KEM coin type |
+
+**Path structure notes:**
+
+- **Purpose (level 0):** Always `44'` (BIP-44). This is the registered BIP-44 purpose for HD wallets. Using a different purpose number (e.g., 204 for PQ-SIG) at level 0 would be non-standard; instead we use distinct **coin_type** values at level 1 to separate algorithm families.
+- **Coin type (level 1):** Distinct coin type per algorithm family: `1237` (Nostr, existing NIP-06), `102001` (SSH/ed25519), `102002` (age/x25519), `102003` (PQ-SIG/ML-DSA), `102004` (PQ-HASH-SIG/SLH-DSA), `102005` (PQ-KEM/ML-KEM). The 102XXX range was chosen because it is unregistered in [SLIP-44](https://github.com/satoshilabs/slips/blob/master/slip-0044.md) and unlikely to be claimed by real cryptocurrencies, avoiding future path collisions.
+- **Account (level 2):** The `<n>` index — this is the `nostr_index` or equivalent role index. Hardened (`'`).
+- **Change (level 3):** `0` for secp256k1 (standard BIP-44 external chain). `0'` (hardened) for ed25519/x25519/PQ because SLIP-0010 requires all-hardened derivation.
+- **Index (level 4):** `0` for secp256k1 (standard BIP-44 first address). `0'` (hardened) for ed25519/x25519/PQ, same SLIP-0010 reason.
+
+**Why all-hardened for ed25519/x25519/PQ:** SLIP-0010 (the standard for ed25519/x25519 HD derivation) requires that every derivation step be hardened — non-hardened derivation is not possible with ed25519 because the public key cannot be used to derive child public keys (the math doesn't work the same as secp256k1). For PQ, we follow the same convention since we're using the path output as a seed, and hardened derivation provides stronger isolation between derived keys.
+
+The path produces a 32-byte seed (512-bit extended key, of which 256 bits are the private key material). For ECC algorithms, this seed IS the private key (or is processed via SLIP-0010's derivation). For PQ algorithms, this seed feeds the deterministic PRNG (SHA-256-DRBG) that replaces PQClean's `randombytes()` during keygen.
+
+### 3.4 New purpose values
+
+Extend [`role_purpose_t`](src/role_table.c:79):
+
+```c
+typedef enum {
+    PURPOSE_NOSTR = 0,
+    PURPOSE_BITCOIN,
+    PURPOSE_SSH,
+    PURPOSE_AGE,
+    PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,      /* new — post-quantum signatures (ML-DSA, SLH-DSA) */
+    PURPOSE_PQ_KEM,      /* new — post-quantum key encapsulation (ML-KEM) */
+    PURPOSE_UNKNOWN
+} role_purpose_t;
+```
+
+### 3.5 New curve values
+
+Extend [`role_curve_t`](src/role_table.c:89):
+
+```c
+typedef enum {
+    CURVE_SECP256K1 = 0,
+    CURVE_ED25519,
+    CURVE_X25519,
+    CURVE_ML_DSA_65,       /* new */
+    CURVE_SLH_DSA_128S,    /* new */
+    CURVE_ML_KEM_768,      /* new */
+    CURVE_UNKNOWN
+} role_curve_t;
+```
+
+String mappings in [`role_curve_from_str`](src/role_table.c:597) / [`role_curve_to_str`](src/role_table.c:631):
+- `"ml-dsa-65"` ↔ `CURVE_ML_DSA_65`
+- `"slh-dsa-128s"` ↔ `CURVE_SLH_DSA_128S`
+- `"ml-kem-768"` ↔ `CURVE_ML_KEM_768`
+
+### 3.6 New verbs
+
+Add verbs for the new crypto operations:
+
+| Verb | Purpose | Curve | Description |
+|---|---|---|---|
+| `get_public_key` | all | all | Already exists; extend to return algorithm-appropriate pubkey format |
+| `sign_data` | pq-sig, ssh | ml-dsa-65, slh-dsa-128s, ed25519 | Sign arbitrary bytes (not a Nostr event) |
+| `verify_signature` | pq-sig, ssh | ml-dsa-65, slh-dsa-128s, ed25519 | Verify a signature (optional — signer can verify, or client verifies) |
+| `kem_encapsulate` | pq-kem | ml-kem-768 | Generate ciphertext + shared secret from peer's ML-KEM public key |
+| `kem_decapsulate` | pq-kem | ml-kem-768 | Decapsulate ciphertext to recover shared secret |
+| `ssh_sign` | ssh | ed25519 | Sign SSH authentication challenge (ed25519-specific format) |
+
+The existing nostr verbs (`sign_event`, `nip44_encrypt`, etc.) remain unchanged and still require `PURPOSE_NOSTR + CURVE_SECP256K1`.
+
+### 3.7 Enforcement rules
+
+Extend [`enforce_verb_role`](src/enforcement.c:468) with new verb→purpose→curve rules:
+
+```c
+/* Nostr verbs: unchanged — PURPOSE_NOSTR + CURVE_SECP256K1 only */
+
+/* sign_data: allowed on PQ-SIG or SSH purposes */
+/*   PURPOSE_PQ_SIG + CURVE_ML_DSA_65 → OK */
+/*   PURPOSE_PQ_SIG + CURVE_SLH_DSA_128S → OK */
+/*   PURPOSE_SSH + CURVE_ED25519 → OK */
+
+/* kem_encapsulate / kem_decapsulate: */
+/*   PURPOSE_PQ_KEM + CURVE_ML_KEM_768 → OK */
+
+/* ssh_sign: */
+/*   PURPOSE_SSH + CURVE_ED25519 → OK */
+```
+
+Fail-closed for any unlisted combination, preserving the existing security model from [`plans/deny_by_default_approvals.md`](plans/deny_by_default_approvals.md).
+
+### 3.8 Public key output format
+
+The `get_public_key` verb currently returns a 64-hex-char secp256k1 pubkey. For PQ keys, the public keys are much larger. The response format changes to include algorithm metadata:
+
+```json
+{
+  "id": "...",
+  "result": {
+    "algorithm": "ml-dsa-65",
+    "public_key": "<hex-encoded, up to ~4KB>",
+    "key_id": "<short identifier for display>"
+  }
+}
+```
+
+For backward compatibility, secp256k1/nostr roles continue to return the plain hex string (the existing format) unless the client requests the structured format via an options flag.
+
+### 3.9 PQClean integration
+
+Vendor PQClean into `resources/pqclean/` with only the three algorithm folders:
+
+```
+resources/pqclean/
+├── crypto_sign/
+│   ├── ml-dsa-65/
+│   │   ├── api.h
+│   │   ├── sign.c
+│   │   ├── params.h
+│   │   └── ... (algorithm-specific files)
+│   └── slh-dsa-128s/
+│       ├── api.h
+│       ├── sign.c
+│       ├── params.h
+│       └── ...
+├── crypto_kem/
+│   └── ml-kem-768/
+│       ├── api.h
+│       ├── kem.c
+│       ├── params.h
+│       └── ...
+├── common/           /* shared utilities (fips202, sha2, randombytes hook) */
+│   ├── fips202.c
+│   ├── sha2.c
+│   └── randombytes.c  /* we replace this with our PRNG */
+└── pqclean.h         /* umbrella include */
+```
+
+Each PQClean algorithm exposes a simple API:
+```c
+int crypto_sign_keypair(unsigned char *pk, unsigned char *sk);  /* uses randombytes() */
+int crypto_sign(unsigned char *sig, size_t *siglen,
+                const unsigned char *m, size_t mlen,
+                const unsigned char *sk);
+int crypto_sign_open(unsigned char *m, size_t *mlen,
+                     const unsigned char *sm, size_t smlen,
+                     const unsigned char *pk);
+
+int crypto_kem_keypair(unsigned char *pk, unsigned char *sk);
+int crypto_kem_enc(unsigned char *ct, unsigned char *ss, const unsigned char *pk);
+int crypto_kem_dec(unsigned char *ss, const unsigned char *ct, const unsigned char *sk);
+```
+
+### 3.10 Deterministic PRNG for PQ keygen
+
+New file `src/pq_drbg.c`:
+
+```c
+/* SHA-256-DRBG seeded from mnemonic-derived seed.
+ * Replaces PQClean's randombytes() for deterministic keygen. */
+
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+```
+
+PQClean's `randombytes.c` is replaced with a shim that calls `pq_drbg_randombytes()`. During keygen, the DRBG is seeded from the mnemonic-derived path seed. After keygen, the DRBG is zeroized.
+
+For signing operations, PQClean's sign functions do not call `randombytes()` (ML-DSA and SLH-DSA are deterministic signatures), so the DRBG is only needed during keygen.
+
+### 3.11 ed25519 / x25519 implementation
+
+**Host (x86_64 static binary):** Use OpenSSL's EVP_PKEY API (already linked via `-lssl -lcrypto` in [`Makefile`](Makefile:3)). Functions:
+- `EVP_PKEY_keygen_init` / `EVP_PKEY_keygen` for key generation
+- `EVP_DigestSign` / `EVP_DigestVerify` for ed25519 signing
+- `EVP_PKEY_derive` for x25519 key agreement
+
+**ESP32 firmware:** Use ESP-IDF's mbedtls component (`mbedtls_ed25519_*`, `mbedtls_ecdh_*` with X25519 curve). Already available in the ESP-IDF dependency tree.
+
+The abstraction in `src/pq_crypto.c` wraps both backends behind the same interface so the dispatcher and key_store are backend-agnostic.
+
+### 3.12 Build system changes
+
+#### Makefile (host)
+
+Add PQClean source files to [`SOURCES`](Makefile:13):
+
+```makefile
+PQCLEAN_DIR := resources/pqclean
+PQCLEAN_SOURCES := \
+    $(PQCLEAN_DIR)/crypto_sign/ml-dsa-65/sign.c \
+    $(PQCLEAN_DIR)/crypto_sign/ml-dsa-65/... \
+    $(PQCLEAN_DIR)/crypto_sign/slh-dsa-128s/sign.c \
+    $(PQCLEAN_DIR)/crypto_sign/slh-dsa-128s/... \
+    $(PQCLEAN_DIR)/crypto_kem/ml-kem-768/kem.c \
+    $(PQCLEAN_DIR)/crypto_kem/ml-kem-768/... \
+    $(PQCLEAN_DIR)/common/fips202.c \
+    $(PQCLEAN_DIR)/common/sha2.c \
+    src/pq_crypto.c \
+    src/pq_drbg.c
+
+SOURCES += $(PQCLEAN_SOURCES)
+CFLAGS += -I$(PQCLEAN_DIR) -I$(PQCLEAN_DIR)/crypto_sign/ml-dsa-65 ...
+```
+
+#### Dockerfile.alpine-musl
+
+No new system packages needed — PQClean is vendored C source compiled by the existing gcc/musl toolchain. The build already has `-lssl -lcrypto` for ed25519/x25519.
+
+#### ESP32 firmware
+
+Add PQClean sources to the firmware CMakeLists.txt. ESP32-S3 has hardware SHA-2 acceleration which benefits SLH-DSA-128s. The PQClean SHA-2 implementation can be replaced with ESP-IDF's hardware-accelerated `mbedtls_sha256` for a significant speedup.
+
+### 3.13 Architecture diagram
+
+```mermaid
+graph TD
+    M[BIP-39 Mnemonic] --> DERIVE[crypto_derive_all]
+    DERIVE --> |m/44'/1237'/n'| SECP[secp256k1 keypair]
+    DERIVE --> |m/44'/1238'/n'| ED25519[ed25519 keypair]
+    DERIVE --> |m/44'/1239'/n'| X25519[x25519 keypair]
+    DERIVE --> |m/44'/204'/n' seed| DRBG[SHA-256-DRBG]
+    DRBG --> |randombytes hook| MLDSA[ML-DSA-65 keypair]
+    DERIVE --> |m/44'/205'/n' seed| DRBG2[SHA-256-DRBG]
+    DRBG2 --> |randombytes hook| SLHDSA[SLH-DSA-128s keypair]
+    DERIVE --> |m/44'/206'/n' seed| DRBG3[SHA-256-DRBG]
+    DRBG3 --> |randombytes hook| MLKEM[ML-KEM-768 keypair]
+
+    SECP --> KS[Key Store - variable length]
+    ED25519 --> KS
+    X25519 --> KS
+    MLDSA --> KS
+    SLHDSA --> KS
+    MLKEM --> KS
+
+    KS --> DISP[Dispatcher]
+    DISP --> |sign_event| SECP
+    DISP --> |sign_data| ED25519
+    DISP --> |sign_data| MLDSA
+    DISP --> |sign_data| SLHDSA
+    DISP --> |kem_encaps/decaps| MLKEM
+    DISP --> |ssh_sign| ED25519
+```
+
+## 4. Implementation phases
+
+### Phase 1 — Foundation: variable-length key store + algorithm registry
+
+**Goal:** Refactor the key store to support variable-length keys and introduce the algorithm abstraction. No new crypto yet — secp256k1 continues to work through the new abstraction.
+
+**Files:**
+- `src/pq_crypto.c` / `pq_crypto.h` (new) — algorithm registry, size tables, `crypto_alg_from_role()`
+- `src/key_store.c` (modify) — replace fixed 32-byte `derived_key_t` with variable-length `secure_buf_t` for both priv and pub; route secp256k1 through the new abstraction
+- `src/role_table.c` (modify) — add new purpose/curve enum values and string mappings
+- `tests/test_key_store.c` (new or extend) — verify secp256k1 still works after refactor
+
+**Exit criteria:**
+- `make test` passes (all existing tests)
+- secp256k1 key derivation and signing works through the new abstraction
+- `derived_key_t` uses `secure_buf_t` for both private and public keys
+- New enum values exist but are not yet wired to crypto
+
+### Phase 2 — ed25519 + x25519 (standard ECC)
+
+**Goal:** Implement ed25519 signing and x25519 key agreement using OpenSSL on host.
+
+**Files:**
+- `src/pq_crypto.c` (extend) — add ed25519 keygen, sign, verify; x25519 keygen, derive
+- `src/key_store.c` (extend) — derive ed25519/x25519 keys from mnemonic via SLIP-0010 paths
+- `src/enforcement.c` (extend) — add `sign_data` and `ssh_sign` verbs for `PURPOSE_SSH + CURVE_ED25519`
+- `src/dispatcher.c` (extend) — handle new verbs
+- `tests/test_pq_crypto.c` (new) — ed25519 sign/verify roundtrip, x25519 ECDH roundtrip
+
+**Exit criteria:**
+- ed25519 key derived from mnemonic, signs data, signature verifies
+- x25519 key derived from mnemonic, ECDH shared secret matches between two derived keys
+- `sign_data` verb works for ed25519
+- Enforcement rejects ed25519 on nostr verbs and vice versa
+
+### Phase 3 — PQClean vendoring + ML-DSA-65
+
+**Goal:** Vendor PQClean, implement deterministic keygen via DRBG, get ML-DSA-65 working.
+
+**Files:**
+- `resources/pqclean/` (new) — vendored PQClean ML-DSA-65 + common files
+- `src/pq_drbg.c` / `pq_drbg.h` (new) — SHA-256-DRBG seeded from mnemonic
+- `resources/pqclean/common/randombytes.c` (replace) — shim calling `pq_drbg_randombytes()`
+- `src/pq_crypto.c` (extend) — ML-DSA-65 keygen, sign, verify
+- `src/key_store.c` (extend) — derive ML-DSA-65 keys via DRBG-seeded keygen
+- `src/enforcement.c` (extend) — `sign_data` for `PURPOSE_PQ_SIG + CURVE_ML_DSA_65`
+- `src/dispatcher.c` (extend) — handle ML-DSA-65 signing
+- `Makefile` (modify) — add PQClean sources
+- `Dockerfile.alpine-musl` (verify) — static build still works with PQClean
+- `tests/test_pq_crypto.c` (extend) — ML-DSA-65 keygen determinism, sign/verify roundtrip, known-answer test
+
+**Exit criteria:**
+- ML-DSA-65 keypair derived deterministically from mnemonic (same mnemonic + role = same keypair)
+- Signature verifies with PQClean's verify function
+- Static binary builds with PQClean linked
+- Known-answer test passes (test vector from NIST or PQClean)
+
+### Phase 4 — SLH-DSA-128s
+
+**Goal:** Add hash-based PQ signatures.
+
+**Files:**
+- `resources/pqclean/crypto_sign/slh-dsa-128s/` (new) — vendored PQClean SLH-DSA-128s
+- `src/pq_crypto.c` (extend) — SLH-DSA-128s keygen, sign, verify
+- `src/key_store.c` (extend) — derive SLH-DSA-128s keys
+- `src/enforcement.c` (extend) — `sign_data` for `PURPOSE_PQ_SIG + CURVE_SLH_DSA_128S`
+- `src/dispatcher.c` (extend) — handle SLH-DSA-128s signing
+- `Makefile` (modify) — add SLH-DSA-128s sources
+- `tests/test_pq_crypto.c` (extend) — SLH-DSA-128s keygen determinism, sign/verify roundtrip
+
+**Exit criteria:**
+- SLH-DSA-128s keypair derived deterministically from mnemonic
+- Signature verifies
+- Known-answer test passes
+- Document the signing latency on ESP32 (measure and record, no mitigation required)
+
+### Phase 5 — ML-KEM-768
+
+**Goal:** Add PQ key encapsulation.
+
+**Files:**
+- `resources/pqclean/crypto_kem/ml-kem-768/` (new) — vendored PQClean ML-KEM-768
+- `src/pq_crypto.c` (extend) — ML-KEM-768 keygen, encaps, decaps
+- `src/key_store.c` (extend) — derive ML-KEM-768 keys
+- `src/enforcement.c` (extend) — `kem_encapsulate` / `kem_decapsulate` for `PURPOSE_PQ_KEM + CURVE_ML_KEM_768`
+- `src/dispatcher.c` (extend) — handle KEM verbs
+- `Makefile` (modify) — add ML-KEM-768 sources
+- `tests/test_pq_crypto.c` (extend) — ML-KEM-768 keygen determinism, encaps/decaps roundtrip, shared secret matches
+
+**Exit criteria:**
+- ML-KEM-768 keypair derived deterministically from mnemonic
+- Encapsulate with public key produces ciphertext + shared secret
+- Decapsulate with private key + ciphertext recovers same shared secret
+- Known-answer test passes
+
+### Phase 6 — Public key output format + client API
+
+**Goal:** Update the `get_public_key` response to handle large PQ public keys and algorithm metadata.
+
+**Files:**
+- `src/dispatcher.c` (modify) — structured `get_public_key` response for non-secp256k1 algorithms
+- `client/` (modify) — client library handles new response format
+- `documents/CLIENT_IMPLEMENTATION.md` (modify) — document new verbs and response formats
+- `examples/` (new) — example clients for PQ signing and KEM
+
+**Exit criteria:**
+- `get_public_key` returns algorithm-appropriate format for all 6 algorithms
+- secp256k1 backward compatibility preserved (plain hex string by default)
+- Client examples demonstrate PQ signing and KEM usage
+
+### Phase 7 — ESP32 firmware port
+
+**Goal:** Get PQ algorithms working on ESP32-S3 firmware.
+
+**Files:**
+- `firmware/feather_s3_tft/main/` (modify) — add PQClean sources to firmware build, replace SHA-2 with hardware-accelerated mbedtls
+- `firmware/feather_s3_tft/CMakeLists.txt` (modify) — add PQClean source files
+- `firmware/cyd_esp32_2432s028/CMakeLists.txt` (modify) — same
+
+**Exit criteria:**
+- ESP32-S3 firmware builds with all 6 algorithms
+- ML-DSA-65 signing works on device (measure latency)
+- SLH-DSA-128s signing works on device (measure and document latency)
+- ML-KEM-768 encaps/decaps works on device
+- ed25519/x25519 work on device via mbedtls
+- Flash usage measured and documented (confirm it fits)
+
+### Phase 8 — Documentation
+
+**Files:**
+- `README.md` (modify) — add PQ algorithms to the crypto palette section, document new verbs
+- `documents/SECURITY.md` (modify) — PQ threat model, deterministic derivation explanation, SLH-DSA latency note
+- `plans/seed_phrase_uses.md` (modify) — add PQ purpose domains to the catalog
+- `documents/CLIENT_IMPLEMENTATION.md` (modify) — full verb reference for new operations
+
+## 5. Threat model considerations
+
+### 5.1 Deterministic PQ key derivation
+
+The mnemonic-seeded DRBG approach is non-standard. There is no NIST or IETF specification for deriving PQ keys from a BIP-39 mnemonic. The security argument:
+
+- The 32-byte seed from BIP-32 derivation has full 256 bits of entropy (assuming the mnemonic has full entropy).
+- SHA-256-DRBG is a NIST-approved DRBG (SP 800-90A). Seeding it with 256 bits of entropy is sufficient for all three PQ algorithms.
+- The alternative (random PQ keys, no mnemonic recovery) breaks n_signer's core model. The deterministic approach is the right tradeoff for this project.
+
+**Risk:** If a weakness is found in using DRBG output as PQ keygen randomness, all PQ keys derived this way could be affected. Mitigation: the DRBG is seeded per-role with distinct derivation paths, so compromising one role's PQ key does not compromise others.
+
+### 5.2 PQ algorithm maturity
+
+ML-DSA, SLH-DSA, and ML-KEM are FIPS-standardized (FIPS 203, 204, 205). They have undergone extensive NIST scrutiny. However, they are newer than classical algorithms. The plan does not replace secp256k1 for Nostr — PQ algorithms are additional options, not replacements.
+
+### 5.3 SLH-DSA-128s signing latency on ESP32
+
+SLH-DSA-128s signing on ESP32 could take 5-30 seconds. This is not a security issue but a UX consideration. The approval prompt flow on the feather/CYD should show a "signing..." indicator during the operation. The user has accepted this and will choose whether to use SLH-DSA-128s per-role.
+
+### 5.4 Key size and memory
+
+PQ private keys are large (ML-DSA-65: 4032 bytes, ML-KEM-768: 2400 bytes). With `ROLE_TABLE_MAX_ENTRIES` at 256, a full table of PQ keys would use ~1MB of mlock'd memory. This is acceptable on host. On ESP32 with 512KB SRAM, the role table should be smaller or PQ roles should be derived on-demand rather than all at startup. The existing on-demand derivation in [`crypto_derive_one`](src/key_store.c:548) already supports this pattern.
+
+## 6. What is explicitly out of scope
+
+1. **Hybrid signatures** (e.g., ed25519 + ML-DSA combined signature). No standard exists yet for SSH. Will be a follow-up when OpenSSH defines the format.
+2. **PQ SSH signing key format**. OpenSSH does not support PQ signing keys yet. We build the primitive; the SSH wire format is future work.
+3. **Bitcoin purpose implementation**. `PURPOSE_BITCOIN` remains modeled but not implemented. Separate plan.
+4. **FIPS purpose with PQ algorithms**. The FIPS mesh transport purpose is orthogonal to the crypto algorithm. Separate concern.
+5. **PQ key persistence**. Breaks the crash-equals-wipe model. Explicitly rejected.
+6. **NIP-44/NIP-04 with PQ keys**. Nostr encryption uses secp256k1 ECDH. PQ KEM is a separate encryption path, not a Nostr NIP.
+7. **liboqs or oqs-provider**. Rejected in favor of PQClean for ESP32 compatibility.
+
+## 7. Open questions
+
+1. **PQ public key encoding for `get_public_key`**: Should PQ public keys be returned as raw hex, base64, or a structured format? Plan defaults to hex for consistency with secp256k1, but PQ pubkeys are large (ML-DSA-65 pub is 1952 bytes = 3904 hex chars). Base64 would be more compact. Decision can be made at implementation time.
+
+2. **Derivation path purpose codes**: The plan proposes `44'/204'`, `44'/205'`, `44'/206'` for PQ-SIG, PQ-HASH-SIG, PQ-KEM. These are unregistered BIP-44 purpose codes. If there is a future standard for PQ derivation paths, these may need to change. Acceptable for now since the derivation is internal to n_signer.
+
+3. **ESP32 role table size for PQ**: Should the firmware limit the number of PQ roles to control memory usage, or rely on on-demand derivation? Plan defaults to on-demand derivation (already supported) with no hard limit change.
+
+4. **Verify-on-signer for `sign_data`**: Should the signer verify its own PQ signatures before returning them to the client? Adds latency but catches implementation bugs. Plan defaults to no (client verifies), matching the existing `sign_event` behavior.
+
+## 8. Files touched summary
+
+| File | Action | Phase |
+|---|---|---|
+| `src/pq_crypto.c` / `pq_crypto.h` | New | 1-5 |
+| `src/pq_drbg.c` / `pq_drbg.h` | New | 3 |
+| `src/key_store.c` | Modify (variable-length keys, new derivations) | 1-5 |
+| `src/role_table.c` | Modify (new enum values, string mappings) | 1 |
+| `src/enforcement.c` | Modify (new verb→purpose→curve rules) | 2-5 |
+| `src/dispatcher.c` | Modify (new verb handlers, structured pubkey response) | 2-6 |
+| `src/main.c` | Modify (headerless decls for new types) | 1-5 |
+| `resources/pqclean/` | New (vendored PQClean) | 3-5 |
+| `Makefile` | Modify (PQClean sources, includes) | 3-5 |
+| `Dockerfile.alpine-musl` | Verify (static build with PQClean) | 3 |
+| `tests/test_pq_crypto.c` | New | 2-5 |
+| `firmware/feather_s3_tft/` | Modify (PQClean in firmware build) | 7 |
+| `firmware/cyd_esp32_2432s028/` | Modify (same) | 7 |
+| `README.md` | Modify (crypto palette, new verbs) | 8 |
+| `documents/SECURITY.md` | Modify (PQ threat model) | 8 |
+| `documents/CLIENT_IMPLEMENTATION.md` | Modify (new verb docs) | 6, 8 |
+| `plans/seed_phrase_uses.md` | Modify (PQ purpose domains) | 8 |
+| `examples/` | New (PQ signing + KEM examples) | 6 |

plans/seed_phrase_uses.md

@@ -92,15 +92,57 @@ This prevents "same seed means same trust domain" mistakes by separating identit
 - Per-service deterministic auth keys (HMAC or asymmetric challenge keys depending on service model).
 - Strongly policy-scoped to avoid accidental cross-service linkage.
 
+### 3.7 Post-quantum signature identities (`purpose="pq-sig"`)
+
+- Candidate curves: `ml-dsa-65`, `slh-dsa-128s`
+- Derivation paths:
+  - ML-DSA-65: `m/44'/102003'/<n>'/0'/0'` → seed → SHAKE-256 DRBG → PQClean keygen
+  - SLH-DSA-128s: `m/44'/102004'/<n>'/0'/0'` → seed → SHAKE-256 DRBG → PQClean keygen
+- Uses:
+  - PQ-aware protocol signatures
+  - future SSH PQ signing keys (when OpenSSH adds support)
+  - general-purpose PQ signatures for forward-looking applications
+- Note: OpenSSH does not yet support PQ signing keys. These are forward-looking — the primitives are ready for when the ecosystem adopts them. See [`plans/post_quantum_crypto.md`](post_quantum_crypto.md) §2.3 for the SSH PQ landscape.
+- Note: SLH-DSA-128s signing on ESP32 can take 5–30 seconds. Choose per-role whether the latency tradeoff is acceptable.
+- Verbs: `sign_data`, `verify_signature` (see [`README.md`](../README.md) §5).
+
+### 3.8 Post-quantum key encapsulation (`purpose="pq-kem"`)
+
+- Candidate curves: `ml-kem-768`
+- Derivation path: `m/44'/102005'/<n>'/0'/0'` → seed → SHAKE-256 DRBG → PQClean keygen
+- Uses:
+  - PQ key agreement for encryption (encapsulate a shared secret against a peer's ML-KEM-768 public key)
+  - hybrid PQ+classical key exchange (client combines ML-KEM-768 with x25519)
+  - future PQ TLS session key establishment
+- Note: ML-KEM-768 addresses the harvest-now-decrypt-later threat for key agreement. See [`documents/SECURITY.md`](../documents/SECURITY.md) §16.1 for the PQ threat model.
+- Verbs: `kem_encapsulate`, `kem_decapsulate` (see [`README.md`](../README.md) §5).
+
 ## 4. Curve and derivation notes
 
-`n_signer` currently models curve metadata from day one:
+`n_signer` models these curves:
 
-- `secp256k1`
-- `ed25519`
-- `x25519`
+- `secp256k1` — Nostr, Bitcoin
+- `ed25519` — SSH signatures
+- `x25519` — key agreement (age)
+- `ml-dsa-65` — PQ signatures (FIPS 204)
+- `slh-dsa-128s` — PQ hash-based signatures (FIPS 205)
+- `ml-kem-768` — PQ key encapsulation (FIPS 203)
 
-Not every purpose should be valid on every curve. Enforcement should be explicit in policy/runtime validation.
+Derivation paths use BIP-44 structure with distinct coin types per algorithm family:
+
+| Algorithm | Coin type | Path | Derivation style |
+|---|---|---|---|
+| secp256k1 (nostr) | 1237 | `m/44'/1237'/<n>'/0/0` | BIP-32 (NIP-06) |
+| secp256k1 (bitcoin) | 0 | `m/44'/0'/<account>'/0/0` etc. | BIP-44 |
+| ed25519 (ssh) | 102001 | `m/44'/102001'/<n>'/0'/0'` | SLIP-0010 (all hardened) |
+| x25519 (age) | 102002 | `m/44'/102002'/<n>'/0'/0'` | SLIP-0010 (all hardened) |
+| ML-DSA-65 (pq-sig) | 102003 | `m/44'/102003'/<n>'/0'/0'` | SLIP-0010 → seed → DRBG → PQClean keygen |
+| SLH-DSA-128s (pq-sig) | 102004 | `m/44'/102004'/<n>'/0'/0'` | SLIP-0010 → seed → DRBG → PQClean keygen |
+| ML-KEM-768 (pq-kem) | 102005 | `m/44'/102005'/<n>'/0'/0'` | SLIP-0010 → seed → DRBG → PQClean keygen |
+
+The 102XXX coin type range is unregistered in SLIP-44 and chosen to avoid collisions with real cryptocurrencies. All non-secp256k1 paths are fully hardened per SLIP-0010. PQ keys use a seed→DRBG→PQClean keygen approach because PQ private keys are not scalars — see [`documents/SECURITY.md`](../documents/SECURITY.md) §16.2 for the security argument.
+
+Not every purpose should be valid on every curve. Enforcement is explicit in the `(verb, purpose, curve)` matrix — see [`README.md`](../README.md) §6.
 
 ## 5. Operational caveats
 

plans/ssh_agent_proxy.md

@@ -0,0 +1,263 @@
+# Plan: SSH Agent Proxy Bridge for n_signer
+
+## 1. Goal
+
+Allow untrusted Qubes qubes to SSH into remote servers using an ed25519 private key held safely in n_signer, without the private key ever leaving the signer qube.
+
+The untrusted qube runs a small proxy program that implements the OpenSSH `ssh-agent` protocol. OpenSSH talks to the proxy as if it were a normal `ssh-agent`. The proxy forwards signing requests to n_signer via qrexec. The private key never touches the untrusted qube's memory.
+
+## 2. Architecture
+
+```mermaid
+graph LR
+    SSH[ssh client in untrusted qube] -->|SSH_AUTH_SOCK| PROXY[nsigner-ssh-agent proxy]
+    PROXY -->|qrexec qubes.NsignerRpc| SIGNER[n_signer in nostr_signer qube]
+    SIGNER -->|derives ed25519 key from mnemonic| KEY[ed25519 private key in mlock'd RAM]
+    SSH -->|SSH protocol| SERVER[remote SSH server]
+```
+
+**Flow:**
+1. User in untrusted qube runs `ssh user@server`
+2. OpenSSH connects to the proxy via `SSH_AUTH_SOCK`
+3. OpenSSH sends `SSH_AGENTC_REQUEST_IDENTITIES` — proxy fetches the ed25519 public key from n_signer and returns it
+4. OpenSSH sends the public key to the remote server as part of `SSH_MSG_USERAUTH_REQUEST`
+5. The server sends back a challenge (the data to sign)
+6. OpenSSH sends `SSH_AGENTC_SIGN_REQUEST` with the challenge data to the proxy
+7. The proxy forwards the data to n_signer via qrexec: `{"method":"sign","params":["<hex>","algorithm":"ed25519","index":0]}`
+8. n_signer signs the data with the ed25519 private key and returns the signature
+9. The proxy returns the signature to OpenSSH
+10. OpenSSH sends the signed authentication response to the server
+
+**Key security property:** The private key exists only in n_signer's mlock'd memory in the `nostr_signer` qube. The untrusted qube never sees it. The proxy only ever handles public keys and signing requests/responses.
+
+## 3. The ssh-agent protocol
+
+OpenSSH's agent protocol is defined in `draft-miller-ssh-agent` (PROTOCOL.agent in the OpenSSH source). It uses a Unix socket with a simple message framing:
+
+**Message format:**
+```
+uint32    message_length
+byte      message_type
+byte[]    message_data
+```
+
+**Messages the proxy must handle:**
+
+### SSH_AGENTC_REQUEST_IDENTITIES (11)
+Request the list of keys the agent holds.
+
+**Response: SSH_AGENT_IDENTITIES_ANSWER (12)**
+```
+uint32    num_keys
+string    key_blob_1       (public key in SSH wire format)
+string    key_comment_1    (human-readable comment)
+string    key_blob_2
+string    key_comment_2
+...
+```
+
+The proxy returns one key: the ed25519 public key from n_signer, formatted as an SSH ed25519 public key blob.
+
+**SSH ed25519 public key blob format:**
+```
+string    "ssh-ed25519"
+string    <32-byte public key>
+```
+
+### SSH_AGENTC_SIGN_REQUEST (13)
+```
+string    key_blob         (the public key to sign with)
+string    data             (the data to sign)
+uint32    flags            (SSH_AGENT_SIGN_FLAG_* — currently 0 or SSH_AGENT_FLAG_RSA_SHA2_256/512 for RSA only)
+```
+
+**Response: SSH_AGENT_SIGN_RESPONSE (14)**
+```
+string    signature_blob
+```
+
+**SSH ed25519 signature blob format:**
+```
+string    "ssh-ed25519"
+string    <64-byte signature>
+```
+
+### Other messages
+- `SSH_AGENTC_REMOVE_ALL_IDENTITIES` (11) — return `SSH_AGENT_SUCCESS`
+- `SSH_AGENTC_REMOVE_IDENTITY` (18) — return `SSH_AGENT_SUCCESS`
+- `SSH_AGENTC_LOCK` / `SSH_AGENTC_UNLOCK` (22/23) — return `SSH_AGENT_SUCCESS`
+- `SSH_AGENTC_ADD_IDENTITY` (17) — return `SSH_AGENT_FAILURE` (we don't allow adding keys)
+- Any unknown message — return `SSH_AGENT_FAILURE` (5)
+
+## 4. Implementation
+
+### 4.1 New program: `nsigner-ssh-agent`
+
+A small C program (~400-500 lines) that:
+
+1. Creates a Unix socket at a configurable path (default: `$XDG_RUNTIME_DIR/nsigner-ssh-agent.sock`)
+2. Listens for connections from OpenSSH
+3. On `SSH_AGENTC_REQUEST_IDENTITIES`:
+   - Calls n_signer via qrexec to get the ed25519 public key: `{"method":"get_public_key","params":[{"algorithm":"ed25519","index":0}]}`
+   - Parses the structured response to extract the 32-byte public key
+   - Formats it as an SSH ed25519 key blob
+   - Returns `SSH_AGENT_IDENTITIES_ANSWER` with one key
+4. On `SSH_AGENTC_SIGN_REQUEST`:
+   - Extracts the data to sign from the request
+   - Calls n_signer via qrexec: `{"method":"sign","params":["<data_hex>",{"algorithm":"ed25519","index":0}]}`
+   - Parses the response to extract the 64-byte signature
+   - Formats it as an SSH ed25519 signature blob
+   - Returns `SSH_AGENT_SIGN_RESPONSE`
+5. On other messages: returns appropriate responses (see §3)
+
+**Key caching:** The proxy caches the public key after the first `REQUEST_IDENTITIES` call (it doesn't change during a session). The private key is never cached — each sign request goes to n_signer.
+
+**Multiple keys:** The proxy can support multiple ed25519 keys by using different `index` values. Configuration via command-line args or environment variables:
+```bash
+nsigner-ssh-agent --index 0 --index 1 --index 2
+```
+Each index produces a different ed25519 key, all derived from the same mnemonic.
+
+### 4.2 qrexec communication
+
+The proxy communicates with n_signer via `qrexec-client-vm nostr_signer qubes.NsignerRpc`, using the same 4-byte big-endian length framing as the existing qrexec examples.
+
+Each qrexec call is a one-shot: spawn `qrexec-client-vm`, send one framed request, receive one framed response, exit. This matches the existing qrexec protocol.
+
+### 4.3 Configuration
+
+**In the untrusted qube:**
+```bash
+# Start the proxy in the background
+nsigner-ssh-agent --socket $XDG_RUNTIME_DIR/nsigner-ssh-agent.sock &
+export SSH_AUTH_SOCK=$XDG_RUNTIME_DIR/nsigner-ssh-agent.sock
+export SSH_AUTH_SIGNER_QUBE=nostr_signer
+
+# Now use ssh normally
+ssh user@server
+```
+
+**In the nostr_signer qube:**
+- n_signer must be running with the mnemonic loaded
+- The `qubes.NsignerRpc` service must be installed
+- The qrexec policy must allow the untrusted qube to call `qubes.NsignerRpc`
+
+**Qubes policy (`packaging/qubes/policy.d/40-nsigner.policy`):**
+```
+nsigner.NsignerRpc +untrusted-qube nostr_signer allow
+```
+
+Or with the deny-by-default model from n_signer's policy:
+```
+nsigner.NsignerRpc +untrusted-qube nostr_signer ask
+```
+The `ask` policy shows a Qubes dom0 prompt each time the untrusted qube tries to sign, giving the user a chance to approve/deny.
+
+### 4.4 n_signer policy
+
+Use n_signer's `--preapprove` to pre-approve the untrusted qube for ed25519 signing:
+```bash
+nsigner --preapprove caller=qubes:untrusted-qube,algorithm=ed25519,index=0,verb=sign,get_public_key
+```
+
+Or use the deny-by-default prompt model — each sign request shows a prompt in the signer qube's TUI:
+```
+Caller: qubes:untrusted-qube
+Action: sign with ed25519
+Key:    index 0 (key_id: 1fd9c73a93189484)
+[a] approve  [d] deny
+```
+
+### 4.5 File structure
+
+```
+src/nsigner_ssh_agent.c     — the proxy program
+packaging/qubes/
+    install-ssh-agent.sh    — install the proxy in an AppVM
+    ssh-agent.desktop       — autostart the proxy on qube boot
+```
+
+### 4.6 Build
+
+The proxy is a separate binary, not part of the main nsigner binary. It links against:
+- cJSON (for JSON-RPC parsing)
+- libnostr_core (for the qrexec transport framing)
+
+Makefile target:
+```makefile
+$(BUILD_DIR)/nsigner-ssh-agent: src/nsigner_ssh_agent.c
+    $(CC) $(CFLAGS) src/nsigner_ssh_agent.c -o $(BUILD_DIR)/nsigner-ssh-agent $(LDFLAGS)
+```
+
+## 5. Security considerations
+
+### 5.1 The untrusted qube sees the public key
+
+The ed25519 public key is sent to the untrusted qube. This is fine — public keys are not secret. The untrusted qube could share the public key with anyone, but that doesn't compromise the private key.
+
+### 5.2 The untrusted qube controls what is signed
+
+The untrusted qube constructs the SSH authentication message and sends it to the proxy for signing. The proxy forwards it to n_signer, which signs it without inspecting the content.
+
+**Risk:** A compromised untrusted qube could ask n_signer to sign arbitrary data, not just SSH authentication messages. The ed25519 signature could be used for purposes other than SSH.
+
+**Mitigation:** This is the same trust model as any ssh-agent. A compromised process with access to `SSH_AUTH_SOCK` can sign arbitrary data. The n_signer policy model (deny-by-default with per-request approval) provides an additional layer: the user can see each sign request at the signer's TUI and approve/deny it.
+
+### 5.3 The proxy holds no secrets
+
+The proxy process in the untrusted qube holds no private key material. It only has:
+- The Unix socket path
+- The qrexec target qube name
+- The cached public key (non-secret)
+- The ed25519 index to use
+
+If the proxy process is compromised, the attacker gains the ability to forward sign requests to n_signer — but n_signer's policy still gates each request.
+
+### 5.4 Qubes qrexec authentication
+
+The qrexec framework authenticates the source qube. n_signer sees the caller as `qubes:<source-vm>`. This means:
+- The signer knows which qube is requesting the signature
+- The Qubes dom0 policy controls which qubes can call the service
+- The n_signer policy can approve specific qubes for specific algorithms/verbs
+
+### 5.5 No private key on disk
+
+The ed25519 private key is never written to disk. It's derived from the mnemonic in n_signer's mlock'd RAM on each startup. The proxy doesn't have the mnemonic. The untrusted qube doesn't have the mnemonic. Only the `nostr_signer` qube has the mnemonic (entered at startup, never persisted).
+
+## 6. What is explicitly out of scope
+
+1. **RSA key support** — the proxy only supports ed25519. RSA SSH keys require different signing (PKCS#1 v1.5 or PSS) and different key derivation. ed25519 is the modern default.
+2. **SSH certificate support** — OpenSSH certificates (ssh-ed25519-cert-v01@openssh.com) are not supported. These require a CA key to sign the certificate, which is a separate workflow.
+3. **Agent forwarding** — `ssh -A` (forwarding the agent to a remote host) is not supported. The proxy only accepts local Unix socket connections.
+4. **Multiple signer qubes** — the proxy talks to one n_signer instance. Multiple signers would require multiple proxy instances.
+5. **Hybrid PQ SSH keys** — OpenSSH doesn't support PQ signing keys yet. When it does, the proxy can be extended to use ML-DSA-65 via n_signer's `sign` verb with `algorithm=ml-dsa-65`.
+
+## 7. Implementation phases
+
+### Phase 1: Core proxy
+- Implement `nsigner-ssh-agent.c` with ssh-agent protocol handling
+- Implement qrexec communication with n_signer
+- Support `SSH_AGENTC_REQUEST_IDENTITIES` and `SSH_AGENTC_SIGN_REQUEST`
+- Test with a real SSH connection
+
+### Phase 2: Qubes integration
+- Install script for AppVMs
+- Autostart on qube boot
+- Qubes policy documentation
+- n_signer `--preapprove` documentation
+
+### Phase 3: Hardening
+- Connection rate limiting (prevent sign-request flooding)
+- Optional: inspect the sign request to verify it looks like an SSH auth message
+- Optional: support multiple ed25519 indices (multiple SSH identities)
+- Optional: support `SSH_AGENTC_REQUEST_EXTENSION` for OpenSSH extensions
+
+## 8. Open questions
+
+1. **Should the proxy inspect the sign request data?** The proxy could check that the data being signed looks like an SSH authentication message (starts with the session ID, has the right message type). This would prevent the untrusted qube from using the signer for non-SSH signing. However, it's fragile (SSH protocol may change) and doesn't match how normal ssh-agents work. Default: no inspection, rely on n_signer's policy.
+
+2. **Should the proxy support `ssh-add -l`?** `ssh-add -l` lists the keys the agent holds, which maps to `SSH_AGENTC_REQUEST_IDENTITIES`. Yes, this is already supported by the protocol handling.
+
+3. **Should the proxy cache the public key across connections?** Yes — the public key doesn't change during a session. Cache it after the first `REQUEST_IDENTITIES` call. Clear the cache on `SIGHUP` or when the qrexec call fails.
+
+4. **Should we support `sk-ssh-ed25519@openssh.com` (security key) key type?** This is the YubiKey key type. It adds a "flags" byte to the signature (e.g., "require user presence"). Not needed for n_signer, but could be useful for compatibility with systems that expect security key signatures. Default: no, use standard `ssh-ed25519`.

src/enforcement.c

@@ -82,6 +82,8 @@ typedef enum {
     PURPOSE_SSH,
     PURPOSE_AGE,
     PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,      /* post-quantum signatures (ML-DSA, SLH-DSA) */
+    PURPOSE_PQ_KEM,      /* post-quantum key encapsulation (ML-KEM) */
     PURPOSE_UNKNOWN
 } role_purpose_t;
 
@@ -90,6 +92,9 @@ typedef enum {
     CURVE_SECP256K1 = 0,
     CURVE_ED25519,
     CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
     CURVE_UNKNOWN
 } role_curve_t;
 
@@ -195,6 +200,24 @@ const char *selector_strerror(int err);
 #define ENFORCE_ERR_PURPOSE      -1 /* purpose mismatch */
 #define ENFORCE_ERR_CURVE        -2 /* curve mismatch */
 #define ENFORCE_ERR_UNKNOWN_VERB -3 /* verb not recognized */
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
 
 /* Known verbs */
 #define VERB_SIGN_EVENT     "sign_event"
@@ -203,6 +226,14 @@ const char *selector_strerror(int err);
 #define VERB_NIP44_DECRYPT  "nip44_decrypt"
 #define VERB_NIP04_ENCRYPT  "nip04_encrypt"
 #define VERB_NIP04_DECRYPT  "nip04_decrypt"
+#define VERB_MINE_EVENT     "mine_event"
+#define VERB_SIGN_DATA      "sign_data"
+#define VERB_VERIFY_SIG     "verify_signature"
+#define VERB_SSH_SIGN       "ssh_sign"
+#define VERB_KEM_ENCAPS     "kem_encapsulate"
+#define VERB_KEM_DECAPS     "kem_decapsulate"
+#define VERB_ENCRYPT        "encrypt"
+#define VERB_DECRYPT        "decrypt"
 
 /*
  * Check whether `verb` is allowed to execute against `role`.
@@ -230,6 +261,8 @@ const char *enforce_strerror(int err);
 #define POLICY_MAX_PURPOSES   8
 #define POLICY_VERB_MAX_LEN   32
 #define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
 
 /* Prompt behavior */
 typedef enum {
@@ -254,6 +287,12 @@ typedef struct {
     int role_count;
     char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
     int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
     prompt_mode_t prompt;
     policy_source_t source;
 } policy_entry_t;
@@ -287,6 +326,20 @@ int policy_check(const policy_table_t *table, const char *caller_id,
                  const char *verb, const char *role_name, const char *purpose,
                  policy_source_t *out_source);
 
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
 /* Parse prompt mode from string */
 prompt_mode_t prompt_mode_from_str(const char *s);
 
@@ -294,15 +347,147 @@ prompt_mode_t prompt_mode_from_str(const char *s);
 const char *prompt_mode_to_str(prompt_mode_t m);
 
 
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,   /* existing, Nostr */
+    CRYPTO_ALG_ED25519,         /* new, SSH signatures */
+    CRYPTO_ALG_X25519,          /* new, key agreement */
+    CRYPTO_ALG_ML_DSA_65,       /* new, PQ signatures */
+    CRYPTO_ALG_SLH_DSA_128S,    /* new, PQ signatures */
+    CRYPTO_ALG_ML_KEM_768,      /* new, PQ KEM */
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;           /* 0 for KEM */
+    size_t ciphertext_len;    /* 0 for signatures */
+    size_t shared_secret_len; /* 0 for signatures */
+} crypto_alg_sizes_t;
+
+/* Get size info for an algorithm. Returns NULL for CRYPTO_ALG_UNKNOWN. */
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+
+/* Map role_curve_t + role_purpose_t to crypto_alg_t.
+ * Returns CRYPTO_ALG_UNKNOWN for unsupported combinations. */
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+
+/* Convert crypto_alg_t to string. Returns NULL for unknown. */
+const char *crypto_alg_to_str(crypto_alg_t alg);
+
+/* Parse string to crypto_alg_t. Returns CRYPTO_ALG_UNKNOWN for unrecognized. */
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+
+
 /* from crypto.h */
 
 
 /* Per-role derived key material (stored in secure memory) */
 typedef struct {
-    secure_buf_t private_key;  /* 32 bytes, mlock'd */
-    unsigned char public_key[32];
-    char pubkey_hex[65];       /* 64 hex chars + null */
-    char npub[128];            /* bech32 npub */
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
     int valid;
 } derived_key_t;
 
@@ -333,6 +518,82 @@ char *crypto_sign_event(const key_store_t *store, int role_index, const char *ev
 void crypto_wipe(key_store_t *store);
 
 
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
 /* from dispatcher.h */
 
 
@@ -341,10 +602,11 @@ typedef struct {
     role_table_t *role_table;
     mnemonic_state_t *mnemonic;
     key_store_t *key_store;
+    algorithm_key_cache_t *alg_key_cache;  /* algorithm-based on-demand keys */
 } dispatcher_ctx_t;
 
 /* Initialize dispatcher context */
-void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store);
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
 
 /*
  * Process a JSON-RPC request string and produce a JSON-RPC response string.
@@ -377,7 +639,7 @@ char *dispatcher_handle_request(dispatcher_ctx_t *ctx, const char *json_request)
 
 
 #define SERVER_SOCKET_NAME_MAX 108
-#define SERVER_MAX_MSG_SIZE    65536
+#define SERVER_MAX_MSG_SIZE    16777216
 
 /* Caller identity */
 typedef struct {
@@ -455,30 +717,198 @@ static int is_nostr_verb(const char *verb) {
         return 0;
     }
 
+    /* get_public_key is a universal verb — allowed for all algorithms.
+     * It is handled separately in enforce_verb_role() and excluded here. */
     return (strcmp(verb, VERB_SIGN_EVENT) == 0) ||
-           (strcmp(verb, VERB_GET_PUBLIC_KEY) == 0) ||
            (strcmp(verb, VERB_NIP44_ENCRYPT) == 0) ||
            (strcmp(verb, VERB_NIP44_DECRYPT) == 0) ||
            (strcmp(verb, VERB_NIP04_ENCRYPT) == 0) ||
-           (strcmp(verb, VERB_NIP04_DECRYPT) == 0);
+           (strcmp(verb, VERB_NIP04_DECRYPT) == 0) ||
+           (strcmp(verb, VERB_MINE_EVENT) == 0);
+}
+
+static int is_sign_data_verb(const char *verb) {
+    if (verb == NULL) {
+        return 0;
+    }
+    return (strcmp(verb, VERB_SIGN_DATA) == 0) ||
+           (strcmp(verb, VERB_VERIFY_SIG) == 0);
+}
+
+static int is_kem_verb(const char *verb) {
+    if (verb == NULL) {
+        return 0;
+    }
+    return (strcmp(verb, VERB_KEM_ENCAPS) == 0) ||
+           (strcmp(verb, VERB_KEM_DECAPS) == 0);
+}
+
+/* Check whether a (purpose, curve) pair is allowed for sign_data / verify_signature.
+ * Returns ENFORCE_OK, ENFORCE_ERR_PURPOSE, or ENFORCE_ERR_CURVE. */
+static int enforce_sign_data_role(const role_entry_t *role) {
+    switch (role->purpose) {
+        case PURPOSE_SSH:
+            if (role->curve == CURVE_ED25519) {
+                return ENFORCE_OK;
+            }
+            return ENFORCE_ERR_CURVE;
+
+        case PURPOSE_PQ_SIG:
+            if (role->curve == CURVE_ML_DSA_65 ||
+                role->curve == CURVE_SLH_DSA_128S) {
+                return ENFORCE_OK;
+            }
+            return ENFORCE_ERR_CURVE;
+
+        default:
+            return ENFORCE_ERR_PURPOSE;
+    }
+}
+
+/* Check whether a (purpose, curve) pair is allowed for kem_encapsulate/decapsulate.
+ * Returns ENFORCE_OK, ENFORCE_ERR_PURPOSE, or ENFORCE_ERR_CURVE. */
+static int enforce_kem_role(const role_entry_t *role) {
+    if (role->purpose != PURPOSE_PQ_KEM) {
+        return ENFORCE_ERR_PURPOSE;
+    }
+    if (role->curve != CURVE_ML_KEM_768) {
+        return ENFORCE_ERR_CURVE;
+    }
+    return ENFORCE_OK;
 }
 
 int enforce_verb_role(const char *verb, const role_entry_t *role) {
-    if (!is_nostr_verb(verb)) {
+    if (verb == NULL || role == NULL) {
         return ENFORCE_ERR_UNKNOWN_VERB;
     }
 
+    /* get_public_key is a universal verb — allowed for any role whose
+     * (curve, purpose) maps to a known algorithm via crypto_alg_from_role().
+     * This lets clients retrieve public keys for all 6 algorithms. */
+    if (strcmp(verb, VERB_GET_PUBLIC_KEY) == 0) {
+        crypto_alg_t alg = crypto_alg_from_role(role->curve, role->purpose);
+        if (alg == CRYPTO_ALG_UNKNOWN) {
+            return ENFORCE_ERR_PURPOSE;
+        }
+        return ENFORCE_OK;
+    }
+
+    /* Nostr verbs: PURPOSE_NOSTR + CURVE_SECP256K1 only. */
+    if (is_nostr_verb(verb)) {
         if (role->purpose != PURPOSE_NOSTR) {
             return ENFORCE_ERR_PURPOSE;
         }
-
         if (role->curve != CURVE_SECP256K1) {
             return ENFORCE_ERR_CURVE;
         }
-
         return ENFORCE_OK;
     }
 
+    /* ssh_sign: PURPOSE_SSH + CURVE_ED25519 only. */
+    if (strcmp(verb, VERB_SSH_SIGN) == 0) {
+        if (role->purpose != PURPOSE_SSH) {
+            return ENFORCE_ERR_PURPOSE;
+        }
+        if (role->curve != CURVE_ED25519) {
+            return ENFORCE_ERR_CURVE;
+        }
+        return ENFORCE_OK;
+    }
+
+    /* sign_data / verify_signature: SSH+ed25519 or PQ-SIG algorithms. */
+    if (is_sign_data_verb(verb)) {
+        return enforce_sign_data_role(role);
+    }
+
+    /* kem_encapsulate / kem_decapsulate: PQ-KEM + ML-KEM-768 only. */
+    if (is_kem_verb(verb)) {
+        return enforce_kem_role(role);
+    }
+
+    /* encrypt / decrypt: allowed for secp256k1 (NIP-04/44), x25519 (age),
+     * and ml-kem-768 (pq-kem). OTP is handled before role resolution. */
+    if (strcmp(verb, VERB_ENCRYPT) == 0 || strcmp(verb, VERB_DECRYPT) == 0) {
+        if (role->curve == CURVE_SECP256K1 && role->purpose == PURPOSE_NOSTR) {
+            return ENFORCE_OK;
+        }
+        if (role->curve == CURVE_X25519 && role->purpose == PURPOSE_AGE) {
+            return ENFORCE_OK;
+        }
+        if (role->curve == CURVE_ML_KEM_768 && role->purpose == PURPOSE_PQ_KEM) {
+            return ENFORCE_OK;
+        }
+        return ENFORCE_ERR_CURVE;
+    }
+
+    return ENFORCE_ERR_UNKNOWN_VERB;
+}
+
+/* ---- Algorithm-based enforcement (new) ----
+ *
+ * enforce_verb_algorithm() checks whether a verb is valid for a given
+ * algorithm, WITHOUT consulting the role table or purpose field. This is
+ * the enforcement path for the new algorithm-based verbs (sign, verify,
+ * encapsulate, decapsulate, derive_shared_secret, get_public_key).
+ *
+ * The Nostr-specific verbs (sign_event, nip44_*, nip04_*, mine_event) are
+ * always secp256k1 — that's a Nostr protocol requirement, not a policy
+ * choice. They are accepted here only when alg == CRYPTO_ALG_SECP256K1
+ * so that algorithm-based policy entries can approve them too.
+ */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg) {
+    if (verb == NULL) {
+        return ENFORCE_ERR_UNKNOWN_VERB;
+    }
+
+    /* get_public_key: valid for all known algorithms. */
+    if (strcmp(verb, VERB_GET_PUBLIC_KEY) == 0) {
+        if (alg == CRYPTO_ALG_UNKNOWN) {
+            return ENFORCE_ERR_ALGORITHM;
+        }
+        return ENFORCE_OK;
+    }
+
+    /* sign / verify: signature algorithms only. */
+    if (strcmp(verb, VERB_SIGN) == 0 || strcmp(verb, VERB_VERIFY) == 0) {
+        if (alg == CRYPTO_ALG_SECP256K1 ||
+            alg == CRYPTO_ALG_ED25519 ||
+            alg == CRYPTO_ALG_ML_DSA_65 ||
+            alg == CRYPTO_ALG_SLH_DSA_128S) {
+            return ENFORCE_OK;
+        }
+        return ENFORCE_ERR_ALGORITHM;
+    }
+
+    /* encapsulate / decapsulate: ML-KEM-768 only. */
+    if (strcmp(verb, VERB_ENCAPSULATE) == 0 || strcmp(verb, VERB_DECAPSULATE) == 0) {
+        if (alg == CRYPTO_ALG_ML_KEM_768) {
+            return ENFORCE_OK;
+        }
+        return ENFORCE_ERR_ALGORITHM;
+    }
+
+    /* derive_shared_secret: x25519 only. */
+    if (strcmp(verb, VERB_DERIVE_SHARED) == 0) {
+        if (alg == CRYPTO_ALG_X25519) {
+            return ENFORCE_OK;
+        }
+        return ENFORCE_ERR_ALGORITHM;
+    }
+
+    /* Nostr verbs: always secp256k1 (protocol requirement). */
+    if (is_nostr_verb(verb) || strcmp(verb, VERB_MINE_EVENT) == 0) {
+        if (alg == CRYPTO_ALG_SECP256K1) {
+            return ENFORCE_OK;
+        }
+        return ENFORCE_ERR_ALGORITHM;
+    }
+
+    /* Old verb aliases map to the new verbs and are handled by the
+     * dispatcher before reaching enforcement. If they reach here,
+     * treat them as unknown (the dispatcher should have remapped). */
+    return ENFORCE_ERR_UNKNOWN_VERB;
+}
+
 const char *enforce_strerror(int err) {
     switch (err) {
         case ENFORCE_OK:
@@ -489,6 +919,8 @@ const char *enforce_strerror(int err) {
             return "curve_mismatch";
         case ENFORCE_ERR_UNKNOWN_VERB:
             return "unknown_verb";
+        case ENFORCE_ERR_ALGORITHM:
+            return "algorithm_not_supported_for_verb";
         default:
             return "unknown_error";
     }

src/http_listener.c

@@ -0,0 +1,220 @@
+/*
+ * http_listener.c — minimal HTTP/1.1 parser for n_signer's HTTP listener mode.
+ *
+ * Only supports POST with a JSON body. No chunked encoding, no keep-alive,
+ * no static file serving. One request per connection (connection close after
+ * response).
+ *
+ * This is intentionally minimal — n_signer is a signer, not a web server.
+ */
+#define _POSIX_C_SOURCE 200809L
+#define _GNU_SOURCE
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <errno.h>
+
+/* ------------------------------------------------------------------ */
+/* Read a line from fd into buf (up to buf_size-1 chars, NUL-terminated).
+ * Returns line length (excluding NUL) on success, -1 on error/EOF.
+ * The line includes the trailing \r\n if present. */
+static int read_line_fd(int fd, char *buf, size_t buf_size) {
+    size_t pos = 0;
+    while (pos < buf_size - 1) {
+        char c;
+        ssize_t n = read(fd, &c, 1);
+        if (n <= 0) {
+            if (pos == 0) return -1;
+            break;
+        }
+        buf[pos++] = c;
+        if (c == '\n') break;
+    }
+    buf[pos] = '\0';
+    return (int)pos;
+}
+
+/* Read exactly n bytes from fd into buf. Returns 0 on success, -1 on error. */
+static int read_n_bytes(int fd, char *buf, size_t n) {
+    size_t got = 0;
+    while (got < n) {
+        ssize_t r = read(fd, buf + got, n - got);
+        if (r <= 0) return -1;
+        got += (size_t)r;
+    }
+    return 0;
+}
+
+/* Write all bytes to fd. Returns 0 on success, -1 on error. */
+static int write_all(int fd, const char *buf, size_t len) {
+    size_t put = 0;
+    while (put < len) {
+        ssize_t w = write(fd, buf + put, len - put);
+        if (w <= 0) {
+            if (errno == EINTR) continue;
+            return -1;
+        }
+        put += (size_t)w;
+    }
+    return 0;
+}
+
+/* ------------------------------------------------------------------ */
+/* Public API                                                         */
+/* ------------------------------------------------------------------ */
+
+/*
+ * Read an HTTP POST request from fd and return the JSON body.
+ *
+ * On success returns 0 and sets *out_body to a malloc'd NUL-terminated
+ * string (caller frees). Returns -1 on error.
+ */
+int http_recv_request(int fd, char **out_body, size_t max_body_size) {
+    char line[2048];
+    long content_length = -1;
+    int is_post = 0;
+
+    if (!out_body) return -1;
+    *out_body = NULL;
+
+    /* Read request line: "METHOD PATH HTTP/1.1\r\n" */
+    if (read_line_fd(fd, line, sizeof(line)) < 0) {
+        return -1;
+    }
+    /* Parse method. */
+    if (strncmp(line, "POST", 4) == 0) {
+        is_post = 1;
+    } else if (strncmp(line, "OPTIONS", 7) == 0) {
+        /* CORS preflight — read remaining headers, then return a special
+         * marker so the caller can send CORS headers. */
+        while (read_line_fd(fd, line, sizeof(line)) > 0) {
+            if (strcmp(line, "\r\n") == 0 || strcmp(line, "\n") == 0) break;
+        }
+        *out_body = strdup("");  /* empty body signals OPTIONS */
+        return 0;
+    }
+
+    if (!is_post) {
+        /* Not POST — read remaining headers so we can send a 405. */
+        while (read_line_fd(fd, line, sizeof(line)) > 0) {
+            if (strcmp(line, "\r\n") == 0 || strcmp(line, "\n") == 0) break;
+        }
+        return -2;  /* method not allowed */
+    }
+
+    /* Read headers until empty line. */
+    while (read_line_fd(fd, line, sizeof(line)) > 0) {
+        /* Strip trailing \r\n. */
+        size_t len = strlen(line);
+        while (len > 0 && (line[len-1] == '\r' || line[len-1] == '\n')) {
+            line[--len] = '\0';
+        }
+        if (len == 0) break;  /* end of headers */
+
+        /* Parse Content-Length (case-insensitive). */
+        if (strncasecmp(line, "Content-Length:", 15) == 0) {
+            const char *p = line + 15;
+            while (*p == ' ' || *p == '\t') p++;
+            content_length = atol(p);
+        }
+    }
+
+    if (content_length < 0) {
+        return -3;  /* missing Content-Length */
+    }
+    if ((size_t)content_length > max_body_size) {
+        /* Drain the body so the connection isn't left half-open. */
+        char tmp[4096];
+        long remaining = content_length;
+        while (remaining > 0) {
+            size_t to_read = (size_t)remaining;
+            if (to_read > sizeof(tmp)) to_read = sizeof(tmp);
+            ssize_t r = read(fd, tmp, to_read);
+            if (r <= 0) break;
+            remaining -= r;
+        }
+        return -4;  /* body too large */
+    }
+
+    /* Read the body. */
+    char *body = (char *)malloc((size_t)content_length + 1);
+    if (!body) return -1;
+    if (read_n_bytes(fd, body, (size_t)content_length) != 0) {
+        free(body);
+        return -1;
+    }
+    body[content_length] = '\0';
+    *out_body = body;
+    return 0;
+}
+
+/*
+ * Send an HTTP response with a JSON body.
+ */
+int http_send_response(int fd, const char *json_body) {
+    if (!json_body) json_body = "";
+    size_t body_len = strlen(json_body);
+
+    char header[512];
+    int hlen = snprintf(header, sizeof(header),
+        "HTTP/1.1 200 OK\r\n"
+        "Content-Type: application/json\r\n"
+        "Content-Length: %zu\r\n"
+        "Access-Control-Allow-Origin: *\r\n"
+        "Access-Control-Allow-Methods: POST, OPTIONS\r\n"
+        "Access-Control-Allow-Headers: Content-Type\r\n"
+        "Connection: close\r\n"
+        "\r\n",
+        body_len);
+
+    if (write_all(fd, header, (size_t)hlen) != 0) return -1;
+    if (write_all(fd, json_body, body_len) != 0) return -1;
+    return 0;
+}
+
+/*
+ * Send an HTTP error response.
+ */
+int http_send_error(int fd, int status, const char *message) {
+    if (!message) message = "error";
+    char body[512];
+    int blen = snprintf(body, sizeof(body),
+        "{\"error\":{\"code\":%d,\"message\":\"%s\"}}", status, message);
+
+    char header[512];
+    int hlen = snprintf(header, sizeof(header),
+        "HTTP/1.1 %d %s\r\n"
+        "Content-Type: application/json\r\n"
+        "Content-Length: %d\r\n"
+        "Access-Control-Allow-Origin: *\r\n"
+        "Connection: close\r\n"
+        "\r\n",
+        status,
+        (status == 405) ? "Method Not Allowed" :
+        (status == 413) ? "Payload Too Large" :
+        (status == 400) ? "Bad Request" : "Internal Server Error",
+        blen);
+
+    if (write_all(fd, header, (size_t)hlen) != 0) return -1;
+    if (write_all(fd, body, (size_t)blen) != 0) return -1;
+    return 0;
+}
+
+/*
+ * Send a CORS preflight response (for OPTIONS requests).
+ */
+int http_send_cors_preflight(int fd) {
+    const char *resp =
+        "HTTP/1.1 204 No Content\r\n"
+        "Access-Control-Allow-Origin: *\r\n"
+        "Access-Control-Allow-Methods: POST, OPTIONS\r\n"
+        "Access-Control-Allow-Headers: Content-Type\r\n"
+        "Access-Control-Max-Age: 86400\r\n"
+        "Content-Length: 0\r\n"
+        "Connection: close\r\n"
+        "\r\n";
+    return write_all(fd, resp, strlen(resp));
+}

src/http_listener.h

@@ -0,0 +1,40 @@
+/*
+ * http_listener.h — minimal HTTP/1.1 parser for n_signer's HTTP listener mode.
+ */
+#ifndef NSIGNER_HTTP_LISTENER_H
+#define NSIGNER_HTTP_LISTENER_H
+
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * Read an HTTP POST request from fd and return the JSON body.
+ * On success returns 0 and sets *out_body to a malloc'd NUL-terminated
+ * string (caller frees). Returns -1 on read error, -2 on method not allowed,
+ * -3 on missing Content-Length, -4 on body too large.
+ */
+int http_recv_request(int fd, char **out_body, size_t max_body_size);
+
+/*
+ * Send an HTTP 200 response with a JSON body.
+ */
+int http_send_response(int fd, const char *json_body);
+
+/*
+ * Send an HTTP error response.
+ */
+int http_send_error(int fd, int status, const char *message);
+
+/*
+ * Send a CORS preflight response (for OPTIONS requests).
+ */
+int http_send_cors_preflight(int fd);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* NSIGNER_HTTP_LISTENER_H */

src/miner.c

@@ -0,0 +1,368 @@
+/*
+ * miner.c - Multithreaded best-effort NIP-13 Proof-of-Work mining coordinator
+ *
+ * This module implements a server-safe mining loop that:
+ *   - Runs N worker threads, each trying nonces with a unique stride
+ *   - Tracks the best event (highest difficulty) across all threads
+ *   - Stops when target difficulty is reached OR timeout expires
+ *   - Always returns the best result found (best-effort, not failure on timeout)
+ *
+ * Unlike the standalone event_miner tool, this code:
+ *   - Has no global variables (all state in context structs)
+ *   - Never calls exit() (returns result codes)
+ *   - Has no signal handlers (the server handles signals)
+ *   - Uses time-based termination as the primary budget
+ */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <time.h>
+#include <pthread.h>
+
+#include <cJSON.h>
+#include <nostr_core/nip001.h>
+#include <nostr_core/nip013.h>
+#include <nostr_core/utils.h>
+
+/* ---- Constants ---- */
+
+#define MINER_MAX_THREADS    32
+#define MINER_SAFETY_TIMEOUT 600  /* 10 minutes safety max when only difficulty is set */
+#define MINER_NONCE_STRIDE   0   /* 0 = use thread_count as stride */
+
+/* ---- Result structure ---- */
+
+typedef struct {
+    cJSON *best_event;        /* best event found (caller frees) */
+    int    achieved_difficulty;
+    int    target_difficulty;
+    int    target_reached;
+    int    elapsed_sec;
+    uint64_t total_attempts;
+} mine_result_t;
+
+/* ---- Shared state across worker threads ---- */
+
+typedef struct {
+    cJSON           *best_event;       /* best event found so far (mutex-protected) */
+    int              best_difficulty;  /* difficulty of best_event */
+    uint64_t         total_attempts;   /* total attempts across all threads */
+    int              target_difficulty;/* 0 = no target, mine full timeout */
+    int              target_reached;   /* 1 if target was reached */
+    pthread_mutex_t  mutex;            /* protects best_event, best_difficulty, total_attempts */
+    volatile int     stop;             /* set when target reached or timeout */
+} mine_shared_state_t;
+
+/* ---- Per-worker context ---- */
+
+typedef struct {
+    mine_shared_state_t *shared;
+    int     kind;
+    char    content[65536];     /* copy of event content */
+    cJSON  *tags_template;      /* this thread's copy of original tags */
+    unsigned char private_key[32];
+    int     thread_id;
+    uint64_t nonce_start;       /* starting nonce for this thread */
+    uint64_t nonce_stride;      /* increment to avoid overlap with other threads */
+    time_t  deadline;           /* absolute time to stop */
+    uint64_t attempts;          /* this thread's attempt count */
+} miner_worker_ctx_t;
+
+/* ---- Helper: update nonce tag in a tags array ---- */
+
+static int miner_update_nonce_tag(cJSON *tags, uint64_t nonce, int target_difficulty) {
+    cJSON *tag;
+    int index = 0;
+
+    if (!tags) return -1;
+
+    /* Remove existing nonce tag if present */
+    cJSON_ArrayForEach(tag, tags) {
+        if (cJSON_IsArray(tag) && cJSON_GetArraySize(tag) >= 2) {
+            cJSON *tag_type = cJSON_GetArrayItem(tag, 0);
+            if (tag_type && cJSON_IsString(tag_type) &&
+                strcmp(cJSON_GetStringValue(tag_type), "nonce") == 0) {
+                cJSON_DetachItemFromArray(tags, index);
+                cJSON_Delete(tag);
+                break;
+            }
+        }
+        index++;
+    }
+
+    /* Add new nonce tag: ["nonce", "<nonce>", "<target>"] */
+    {
+        cJSON *nonce_tag = cJSON_CreateArray();
+        char nonce_str[32];
+        char difficulty_str[16];
+
+        if (!nonce_tag) return -1;
+
+        snprintf(nonce_str, sizeof(nonce_str), "%llu", (unsigned long long)nonce);
+        snprintf(difficulty_str, sizeof(difficulty_str), "%d", target_difficulty);
+
+        cJSON_AddItemToArray(nonce_tag, cJSON_CreateString("nonce"));
+        cJSON_AddItemToArray(nonce_tag, cJSON_CreateString(nonce_str));
+        cJSON_AddItemToArray(nonce_tag, cJSON_CreateString(difficulty_str));
+
+        cJSON_AddItemToArray(tags, nonce_tag);
+    }
+    return 0;
+}
+
+/* ---- Worker thread function ---- */
+
+static void *miner_worker(void *arg) {
+    miner_worker_ctx_t *ctx = (miner_worker_ctx_t *)arg;
+    uint64_t nonce = ctx->nonce_start;
+    time_t current_ts = time(NULL);
+
+    while (!ctx->shared->stop && time(NULL) < ctx->deadline) {
+        cJSON *working_tags;
+        cJSON *signed_event;
+        const char *event_id;
+        int difficulty;
+
+        /* Build tags with current nonce */
+        working_tags = cJSON_Duplicate(ctx->tags_template, 1);
+        if (!working_tags) break;
+
+        if (miner_update_nonce_tag(working_tags, nonce, ctx->shared->target_difficulty) != 0) {
+            cJSON_Delete(working_tags);
+            break;
+        }
+
+        /* Update timestamp periodically (every 1000 attempts) to keep it fresh */
+        if (ctx->attempts % 1000 == 0) {
+            current_ts = time(NULL);
+        }
+
+        /* Create and sign the event with this nonce */
+        signed_event = nostr_create_and_sign_event(ctx->kind, ctx->content,
+                                                    working_tags, ctx->private_key,
+                                                    current_ts);
+        cJSON_Delete(working_tags);
+
+        if (!signed_event) {
+            nonce += ctx->nonce_stride;
+            ctx->attempts++;
+            continue;
+        }
+
+        /* Check difficulty of the resulting event id */
+        {
+            cJSON *id_item = cJSON_GetObjectItem(signed_event, "id");
+            if (!id_item || !cJSON_IsString(id_item)) {
+                cJSON_Delete(signed_event);
+                nonce += ctx->nonce_stride;
+                ctx->attempts++;
+                continue;
+            }
+            event_id = cJSON_GetStringValue(id_item);
+        }
+
+        difficulty = nostr_calculate_pow_difficulty(event_id);
+
+        /* Track best under mutex */
+        pthread_mutex_lock(&ctx->shared->mutex);
+        ctx->shared->total_attempts++;
+        if (difficulty > ctx->shared->best_difficulty) {
+            if (ctx->shared->best_event) {
+                cJSON_Delete(ctx->shared->best_event);
+            }
+            ctx->shared->best_event = cJSON_Duplicate(signed_event, 1);
+            ctx->shared->best_difficulty = difficulty;
+        }
+        if (ctx->shared->target_difficulty > 0 && difficulty >= ctx->shared->target_difficulty) {
+            ctx->shared->target_reached = 1;
+            ctx->shared->stop = 1;
+        }
+        pthread_mutex_unlock(&ctx->shared->mutex);
+
+        cJSON_Delete(signed_event);
+        nonce += ctx->nonce_stride;
+        ctx->attempts++;
+    }
+
+    return NULL;
+}
+
+/* ---- Main mining coordinator ---- */
+
+/*
+ * Run multithreaded best-effort mining on `event`.
+ *
+ * Parameters:
+ *   event            - cJSON event to mine (must have kind, content, tags, created_at)
+ *   private_key      - 32-byte private key for signing
+ *   target_difficulty - 0 = no target (mine full timeout); >0 = stop when reached
+ *   thread_count     - number of worker threads (1..MINER_MAX_THREADS)
+ *   timeout_sec      - time budget in seconds (0 = use MINER_SAFETY_TIMEOUT)
+ *   result           - output struct (caller frees result->best_event)
+ *
+ * Returns 0 on success (result populated), -1 on error.
+ */
+int miner_run(cJSON *event, const unsigned char *private_key,
+              int target_difficulty, int thread_count, int timeout_sec,
+              mine_result_t *result)
+{
+    mine_shared_state_t shared;
+    miner_worker_ctx_t *workers = NULL;
+    pthread_t *threads = NULL;
+    cJSON *kind_item, *content_item, *tags_item, *created_at_item;
+    int kind;
+    const char *content;
+    time_t start_time;
+    int effective_timeout;
+    int i;
+    int ret = 0;
+
+    if (!event || !private_key || !result) {
+        return -1;
+    }
+
+    memset(result, 0, sizeof(mine_result_t));
+
+    /* Validate event has required fields */
+    kind_item = cJSON_GetObjectItem(event, "kind");
+    content_item = cJSON_GetObjectItem(event, "content");
+    tags_item = cJSON_GetObjectItem(event, "tags");
+    created_at_item = cJSON_GetObjectItem(event, "created_at");
+
+    if (!kind_item || !content_item || !tags_item) {
+        return -1;
+    }
+
+    /* If created_at is missing, add it with current time */
+    if (!created_at_item) {
+        cJSON_AddNumberToObject(event, "created_at", (double)time(NULL));
+    }
+
+    kind = (int)cJSON_GetNumberValue(kind_item);
+    content = cJSON_GetStringValue(content_item);
+    if (!content) {
+        content = "";
+    }
+
+    /* Clamp thread count */
+    if (thread_count < 1) thread_count = 1;
+    if (thread_count > MINER_MAX_THREADS) thread_count = MINER_MAX_THREADS;
+
+    /* Determine effective timeout */
+    if (timeout_sec <= 0) {
+        effective_timeout = MINER_SAFETY_TIMEOUT;
+    } else {
+        effective_timeout = timeout_sec;
+    }
+
+    /* Initialize shared state */
+    memset(&shared, 0, sizeof(shared));
+    shared.best_event = NULL;
+    shared.best_difficulty = -1;
+    shared.total_attempts = 0;
+    shared.target_difficulty = target_difficulty;
+    shared.target_reached = 0;
+    shared.stop = 0;
+    if (pthread_mutex_init(&shared.mutex, NULL) != 0) {
+        return -1;
+    }
+
+    /* Allocate worker contexts and thread array */
+    workers = (miner_worker_ctx_t *)calloc(thread_count, sizeof(miner_worker_ctx_t));
+    threads = (pthread_t *)calloc(thread_count, sizeof(pthread_t));
+    if (!workers || !threads) {
+        free(workers);
+        free(threads);
+        pthread_mutex_destroy(&shared.mutex);
+        return -1;
+    }
+
+    start_time = time(NULL);
+
+    /* Set up each worker */
+    for (i = 0; i < thread_count; i++) {
+        workers[i].shared = &shared;
+        workers[i].kind = kind;
+        strncpy(workers[i].content, content, sizeof(workers[i].content) - 1);
+        workers[i].content[sizeof(workers[i].content) - 1] = '\0';
+        workers[i].tags_template = cJSON_Duplicate(tags_item, 1);
+        memcpy(workers[i].private_key, private_key, 32);
+        workers[i].thread_id = i;
+        workers[i].nonce_start = (uint64_t)i;
+        workers[i].nonce_stride = (uint64_t)thread_count;
+        workers[i].deadline = start_time + effective_timeout;
+        workers[i].attempts = 0;
+
+        if (!workers[i].tags_template) {
+            /* Allocation failed for this worker's tags — clean up what we have */
+            int j;
+            for (j = 0; j < i; j++) {
+                cJSON_Delete(workers[j].tags_template);
+            }
+            free(workers);
+            free(threads);
+            pthread_mutex_destroy(&shared.mutex);
+            return -1;
+        }
+    }
+
+    /* Start threads */
+    for (i = 0; i < thread_count; i++) {
+        if (pthread_create(&threads[i], NULL, miner_worker, &workers[i]) != 0) {
+            /* Failed to create thread i — signal stop and join what we have */
+            shared.stop = 1;
+            {
+                int j;
+                for (j = 0; j < i; j++) {
+                    pthread_join(threads[j], NULL);
+                }
+            }
+            ret = -1;
+            goto cleanup;
+        }
+    }
+
+    /* Wait for all threads to complete (they stop on target/timeout) */
+    for (i = 0; i < thread_count; i++) {
+        pthread_join(threads[i], NULL);
+    }
+
+cleanup:
+    /* Sum up total attempts from all workers */
+    {
+        uint64_t total = 0;
+        for (i = 0; i < thread_count; i++) {
+            total += workers[i].attempts;
+        }
+        /* Use the shared counter (more accurate, includes mutex-protected increments) */
+        result->total_attempts = shared.total_attempts > 0 ? shared.total_attempts : total;
+    }
+
+    /* Populate result */
+    result->best_event = shared.best_event;  /* transfer ownership */
+    result->achieved_difficulty = shared.best_difficulty;
+    result->target_difficulty = target_difficulty;
+    result->target_reached = shared.target_reached;
+    result->elapsed_sec = (int)(time(NULL) - start_time);
+
+    /* Clean up worker contexts */
+    for (i = 0; i < thread_count; i++) {
+        if (workers[i].tags_template) {
+            cJSON_Delete(workers[i].tags_template);
+        }
+        /* Zeroize private key copy */
+        memset(workers[i].private_key, 0, 32);
+    }
+
+    free(workers);
+    free(threads);
+    pthread_mutex_destroy(&shared.mutex);
+
+    return ret;
+}

src/mnemonic.c

@@ -82,6 +82,8 @@ typedef enum {
     PURPOSE_SSH,
     PURPOSE_AGE,
     PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,      /* post-quantum signatures (ML-DSA, SLH-DSA) */
+    PURPOSE_PQ_KEM,      /* post-quantum key encapsulation (ML-KEM) */
     PURPOSE_UNKNOWN
 } role_purpose_t;
 
@@ -90,6 +92,9 @@ typedef enum {
     CURVE_SECP256K1 = 0,
     CURVE_ED25519,
     CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
     CURVE_UNKNOWN
 } role_curve_t;
 
@@ -195,6 +200,24 @@ const char *selector_strerror(int err);
 #define ENFORCE_ERR_PURPOSE      -1 /* purpose mismatch */
 #define ENFORCE_ERR_CURVE        -2 /* curve mismatch */
 #define ENFORCE_ERR_UNKNOWN_VERB -3 /* verb not recognized */
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
 
 /* Known verbs */
 #define VERB_SIGN_EVENT     "sign_event"
@@ -230,6 +253,8 @@ const char *enforce_strerror(int err);
 #define POLICY_MAX_PURPOSES   8
 #define POLICY_VERB_MAX_LEN   32
 #define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
 
 /* Prompt behavior */
 typedef enum {
@@ -254,6 +279,12 @@ typedef struct {
     int role_count;
     char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
     int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
     prompt_mode_t prompt;
     policy_source_t source;
 } policy_entry_t;
@@ -287,6 +318,20 @@ int policy_check(const policy_table_t *table, const char *caller_id,
                  const char *verb, const char *role_name, const char *purpose,
                  policy_source_t *out_source);
 
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
 /* Parse prompt mode from string */
 prompt_mode_t prompt_mode_from_str(const char *s);
 
@@ -294,15 +339,147 @@ prompt_mode_t prompt_mode_from_str(const char *s);
 const char *prompt_mode_to_str(prompt_mode_t m);
 
 
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,   /* existing, Nostr */
+    CRYPTO_ALG_ED25519,         /* new, SSH signatures */
+    CRYPTO_ALG_X25519,          /* new, key agreement */
+    CRYPTO_ALG_ML_DSA_65,       /* new, PQ signatures */
+    CRYPTO_ALG_SLH_DSA_128S,    /* new, PQ signatures */
+    CRYPTO_ALG_ML_KEM_768,      /* new, PQ KEM */
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;           /* 0 for KEM */
+    size_t ciphertext_len;    /* 0 for signatures */
+    size_t shared_secret_len; /* 0 for signatures */
+} crypto_alg_sizes_t;
+
+/* Get size info for an algorithm. Returns NULL for CRYPTO_ALG_UNKNOWN. */
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+
+/* Map role_curve_t + role_purpose_t to crypto_alg_t.
+ * Returns CRYPTO_ALG_UNKNOWN for unsupported combinations. */
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+
+/* Convert crypto_alg_t to string. Returns NULL for unknown. */
+const char *crypto_alg_to_str(crypto_alg_t alg);
+
+/* Parse string to crypto_alg_t. Returns CRYPTO_ALG_UNKNOWN for unrecognized. */
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+
+
 /* from crypto.h */
 
 
 /* Per-role derived key material (stored in secure memory) */
 typedef struct {
-    secure_buf_t private_key;  /* 32 bytes, mlock'd */
-    unsigned char public_key[32];
-    char pubkey_hex[65];       /* 64 hex chars + null */
-    char npub[128];            /* bech32 npub */
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
     int valid;
 } derived_key_t;
 
@@ -333,6 +510,82 @@ char *crypto_sign_event(const key_store_t *store, int role_index, const char *ev
 void crypto_wipe(key_store_t *store);
 
 
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
 /* from dispatcher.h */
 
 
@@ -341,10 +594,11 @@ typedef struct {
     role_table_t *role_table;
     mnemonic_state_t *mnemonic;
     key_store_t *key_store;
+    algorithm_key_cache_t *alg_key_cache;  /* algorithm-based on-demand keys */
 } dispatcher_ctx_t;
 
 /* Initialize dispatcher context */
-void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store);
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
 
 /*
  * Process a JSON-RPC request string and produce a JSON-RPC response string.
@@ -377,7 +631,7 @@ char *dispatcher_handle_request(dispatcher_ctx_t *ctx, const char *json_request)
 
 
 #define SERVER_SOCKET_NAME_MAX 108
-#define SERVER_MAX_MSG_SIZE    65536
+#define SERVER_MAX_MSG_SIZE    16777216
 
 /* Caller identity */
 typedef struct {

src/otp_pad.c

@@ -0,0 +1,585 @@
+/*
+ * otp_pad.c — OTP pad state for n_signer.
+ *
+ * One pad per session (by design — see plans/otp_nostr_integration.md).
+ * The pad is bound at startup via otp_pad_bind() and accessed by the
+ * otp_encrypt / otp_decrypt dispatcher verbs via otp_pad_get_state().
+ *
+ * The pad file is opened read-only and kept open for the lifetime of the
+ * process. The per-pad .state file (offset counter) is read and written
+ * via libotppad. Offset writes are atomic (temp + rename) inside libotppad.
+ *
+ * Pad bytes are never loaded whole into RAM. Each request seeks to the
+ * current offset and reads exactly the slice it needs into a small
+ * mlock'd scratch buffer.
+ */
+#define _POSIX_C_SOURCE 200809L
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <errno.h>
+
+#include "libotppad.h"
+#include "otp_pad.h"
+
+/* from secure_mem.h (headerless decls pattern) */
+extern void secure_memzero(void *ptr, size_t len);
+
+/* ------------------------------------------------------------------ */
+/* OTP pad state                                                      */
+/* ------------------------------------------------------------------ */
+
+#define OTP_PAD_DIR_MAX     512
+#define OTP_PAD_CHKSUM_MAX  128
+#define OTP_PAD_PATH_MAX    (OTP_PAD_DIR_MAX + OTP_PAD_CHKSUM_MAX + 16)
+#define OTP_SCRATCH_MAX     (4 * 1024 * 1024)  /* 4 MB max chunk */
+
+typedef struct {
+    int      bound;                          /* 1 if a pad is bound */
+    char     pads_dir[OTP_PAD_DIR_MAX];      /* directory holding .pad/.state */
+    char     chksum[OTP_PAD_CHKSUM_MAX];     /* 64-hex-char pad checksum */
+    char     pad_path[OTP_PAD_PATH_MAX];     /* full path to .pad file */
+    FILE    *pad_fp;                         /* read-only FILE* on .pad */
+    uint64_t pad_size;                       /* total pad file size in bytes */
+    int      allow_blkback;                  /* 1 if --otp-allow-blkback passed */
+    /* mlock'd scratch buffer for XOR */
+    void    *scratch_data;
+    size_t   scratch_size;
+    int      scratch_locked;
+} otp_pad_state_t;
+
+static otp_pad_state_t g_otp_pad = {0};
+
+otp_pad_state_t *otp_pad_get_state(void) {
+    return &g_otp_pad;
+}
+
+int otp_pad_is_bound(void) {
+    return g_otp_pad.bound;
+}
+
+const char *otp_pad_chksum(void) {
+    return g_otp_pad.bound ? g_otp_pad.chksum : NULL;
+}
+
+const char *otp_pad_dir(void) {
+    return g_otp_pad.bound ? g_otp_pad.pads_dir : NULL;
+}
+
+/* ------------------------------------------------------------------ */
+/* Removable-mount check (Qubes guard)                                */
+/* ------------------------------------------------------------------ */
+
+/* Return 1 if `path` lives on a blkback device (e.g. /dev/xvdi via qvm-block),
+ * 0 if it's a directly-owned device (e.g. /dev/sda via PCI passthrough),
+ * -1 on error. Best-effort: compares the fs source device name. */
+static int is_blkback_mount(const char *path) {
+    struct stat st;
+    if (stat(path, &st) != 0) return -1;
+
+    /* Read the mount source for the filesystem containing `path`. */
+    FILE *mtab = fopen("/proc/mounts", "r");
+    if (!mtab) return -1;
+
+    char line[1024];
+    int found = 0;
+    int is_blkback = 0;
+    size_t best_len = 0;
+
+    while (fgets(line, sizeof(line), mtab)) {
+        char source[512], mount[512], fstype[64];
+        if (sscanf(line, "%511s %511s %63s", source, mount, fstype) < 3) continue;
+        size_t mlen = strlen(mount);
+        /* Pick the longest matching mount prefix. */
+        if (strncmp(path, mount, mlen) == 0 &&
+            (path[mlen] == '/' || path[mlen] == '\0') &&
+            mlen > best_len) {
+            best_len = mlen;
+            found = 1;
+            /* blkback devices show up as /dev/xvd* in the guest. */
+            is_blkback = (strncmp(source, "/dev/xvd", 8) == 0);
+        }
+    }
+    fclose(mtab);
+    if (!found) return -1;
+    return is_blkback;
+}
+
+/* ------------------------------------------------------------------ */
+/* Find a pad by chksum prefix in pads_dir                            */
+/* ------------------------------------------------------------------ */
+
+/* Resolve a chksum-or-prefix to a full 64-char chksum by scanning pads_dir.
+ * Returns 0 on success and fills `out_chksum` (must be >= OTP_PAD_CHKSUM_MAX).
+ * Returns -1 if not found, -2 if ambiguous (multiple matches). */
+static int resolve_pad_chksum(const char *pads_dir, const char *prefix,
+                              char *out_chksum) {
+    DIR *d = opendir(pads_dir);
+    if (!d) return -1;
+
+    struct dirent *e;
+    int matches = 0;
+    char found[OTPPAD_CHKSUM_HEX_LEN + 1] = {0};
+    size_t plen = strlen(prefix);
+
+    while ((e = readdir(d)) != NULL) {
+        size_t nlen = strlen(e->d_name);
+        if (nlen < 5 || strcmp(e->d_name + nlen - 4, ".pad") != 0) continue;
+        size_t base_len = nlen - 4;  /* without ".pad" */
+        if (base_len != OTPPAD_CHKSUM_HEX_LEN) continue;
+        if (plen == 0 || strncmp(e->d_name, prefix, plen) == 0) {
+            memcpy(found, e->d_name, base_len);
+            found[base_len] = '\0';
+            matches++;
+        }
+    }
+    closedir(d);
+
+    if (matches == 0) return -1;
+    if (matches > 1) return -2;
+    strncpy(out_chksum, found, OTPPAD_CHKSUM_HEX_LEN);
+    out_chksum[OTPPAD_CHKSUM_HEX_LEN] = '\0';
+    return 0;
+}
+
+/* ------------------------------------------------------------------ */
+/* Bind / unbind                                                      */
+/* ------------------------------------------------------------------ */
+
+/* Bind a pad at startup. Returns 0 on success, non-zero on error.
+ * `pads_dir` is the directory containing <chksum>.pad and <chksum>.state.
+ * `pad_spec` is a full 64-char chksum or a unique prefix.
+ * `allow_blkback` non-zero skips the blkback guard (for qvm-block testing). */
+int otp_pad_bind(const char *pads_dir, const char *pad_spec, int allow_blkback) {
+    if (!pads_dir || !pad_spec) return 1;
+    if (g_otp_pad.bound) return 2;  /* already bound */
+
+    /* Removable-mount guard. */
+    int blkback = is_blkback_mount(pads_dir);
+    if (blkback < 0) {
+        /* Could not determine — warn but continue (best-effort). */
+        fprintf(stderr, "otp_pad: warning: could not determine mount type for %s\n",
+                pads_dir);
+    } else if (blkback && !allow_blkback) {
+        fprintf(stderr, "otp_pad: %s is on a blkback device (qvm-block).\n",
+                pads_dir);
+        fprintf(stderr, "  Refusing to bind for pad secrecy. Use PCI USB "
+                        "controller passthrough, or pass --otp-allow-blkback "
+                        "to override (not recommended for production pads).\n");
+        return 3;
+    }
+
+    /* Resolve the pad chksum. */
+    char chksum[OTPPAD_CHKSUM_HEX_LEN + 1];
+    if (strlen(pad_spec) == OTPPAD_CHKSUM_HEX_LEN) {
+        strncpy(chksum, pad_spec, OTPPAD_CHKSUM_HEX_LEN);
+        chksum[OTPPAD_CHKSUM_HEX_LEN] = '\0';
+        /* Verify the file exists. */
+        char path[OTP_PAD_PATH_MAX];
+        snprintf(path, sizeof(path), "%s/%s.pad", pads_dir, chksum);
+        if (access(path, R_OK) != 0) {
+            fprintf(stderr, "otp_pad: pad file not found: %s\n", path);
+            return 4;
+        }
+    } else {
+        int r = resolve_pad_chksum(pads_dir, pad_spec, chksum);
+        if (r == -1) {
+            fprintf(stderr, "otp_pad: no pad matching prefix '%s' in %s\n",
+                    pad_spec, pads_dir);
+            return 5;
+        } else if (r == -2) {
+            fprintf(stderr, "otp_pad: ambiguous pad prefix '%s' (multiple matches)\n",
+                    pad_spec);
+            return 6;
+        }
+    }
+
+    /* Build the pad path and open it read-only. */
+    char pad_path[OTP_PAD_PATH_MAX];
+    snprintf(pad_path, sizeof(pad_path), "%s/%s.pad", pads_dir, chksum);
+
+    FILE *fp = fopen(pad_path, "rb");
+    if (!fp) {
+        fprintf(stderr, "otp_pad: cannot open %s: %s\n", pad_path, strerror(errno));
+        return 7;
+    }
+
+    /* Determine pad size. */
+    struct stat st;
+    if (fstat(fileno(fp), &st) != 0) {
+        fprintf(stderr, "otp_pad: fstat failed: %s\n", strerror(errno));
+        fclose(fp);
+        return 8;
+    }
+    if (st.st_size < (off_t)OTPPAD_HEADER_RESERVED) {
+        fprintf(stderr, "otp_pad: pad too small (%lld bytes, need >= %d)\n",
+                (long long)st.st_size, OTPPAD_HEADER_RESERVED);
+        fclose(fp);
+        return 9;
+    }
+
+    /* Verify the pad checksum matches the filename. */
+    char computed[OTPPAD_CHKSUM_HEX_LEN + 1];
+    if (otppad_checksum(pad_path, computed) != 0) {
+        fprintf(stderr, "otp_pad: checksum computation failed\n");
+        fclose(fp);
+        return 10;
+    }
+    if (strcmp(computed, chksum) != 0) {
+        fprintf(stderr, "otp_pad: checksum mismatch (file says %s, computed %s)\n",
+                chksum, computed);
+        fclose(fp);
+        return 11;
+    }
+
+    /* Read the current offset. */
+    uint64_t offset;
+    if (otppad_state_read(pads_dir, chksum, &offset) != 0) {
+        /* No state file — initialize at the reserved header. */
+        offset = OTPPAD_HEADER_RESERVED;
+        if (otppad_state_write(pads_dir, chksum, offset) != 0) {
+            fprintf(stderr, "otp_pad: cannot write initial state file\n");
+            fclose(fp);
+            return 12;
+        }
+    }
+    if (offset < OTPPAD_HEADER_RESERVED) {
+        fprintf(stderr, "otp_pad: offset %llu < reserved header %d\n",
+                (unsigned long long)offset, OTPPAD_HEADER_RESERVED);
+        fclose(fp);
+        return 13;
+    }
+    if (offset > (uint64_t)st.st_size) {
+        fprintf(stderr, "otp_pad: offset %llu past end of pad (%lld)\n",
+                (unsigned long long)offset, (long long)st.st_size);
+        fclose(fp);
+        return 14;
+    }
+
+    /* Commit. */
+    strncpy(g_otp_pad.pads_dir, pads_dir, OTP_PAD_DIR_MAX - 1);
+    strncpy(g_otp_pad.chksum, chksum, OTP_PAD_CHKSUM_MAX - 1);
+    strncpy(g_otp_pad.pad_path, pad_path, OTP_PAD_PATH_MAX - 1);
+    g_otp_pad.pad_fp = fp;
+    g_otp_pad.pad_size = (uint64_t)st.st_size;
+    g_otp_pad.allow_blkback = allow_blkback;
+    g_otp_pad.bound = 1;
+
+    fprintf(stderr, "otp_pad: bound pad %s (%llu bytes, offset=%llu)\n",
+            chksum, (unsigned long long)st.st_size,
+            (unsigned long long)offset);
+    return 0;
+}
+
+void otp_pad_unbind(void) {
+    if (g_otp_pad.pad_fp) {
+        fclose(g_otp_pad.pad_fp);
+        g_otp_pad.pad_fp = NULL;
+    }
+    if (g_otp_pad.scratch_data) {
+        secure_memzero(g_otp_pad.scratch_data, g_otp_pad.scratch_size);
+        if (g_otp_pad.scratch_locked) {
+            munlock(g_otp_pad.scratch_data, g_otp_pad.scratch_size);
+        }
+        free(g_otp_pad.scratch_data);
+        g_otp_pad.scratch_data = NULL;
+        g_otp_pad.scratch_size = 0;
+        g_otp_pad.scratch_locked = 0;
+    }
+    secure_memzero(&g_otp_pad, sizeof(g_otp_pad));
+}
+
+/* ------------------------------------------------------------------ */
+/* Core encrypt/decrypt transform                                     */
+/* ------------------------------------------------------------------ */
+
+/* Ensure the scratch buffer is at least `size` bytes, mlock'd. */
+static int ensure_scratch(size_t size) {
+    if (size > OTP_SCRATCH_MAX) return -1;
+    if (g_otp_pad.scratch_size >= size && g_otp_pad.scratch_data) return 0;
+    /* Grow. */
+    if (g_otp_pad.scratch_data) {
+        secure_memzero(g_otp_pad.scratch_data, g_otp_pad.scratch_size);
+        if (g_otp_pad.scratch_locked) {
+            munlock(g_otp_pad.scratch_data, g_otp_pad.scratch_size);
+        }
+        free(g_otp_pad.scratch_data);
+        g_otp_pad.scratch_data = NULL;
+        g_otp_pad.scratch_size = 0;
+        g_otp_pad.scratch_locked = 0;
+    }
+    g_otp_pad.scratch_data = malloc(size);
+    if (!g_otp_pad.scratch_data) return -2;
+    g_otp_pad.scratch_size = size;
+    if (mlock(g_otp_pad.scratch_data, size) == 0) {
+        g_otp_pad.scratch_locked = 1;
+    }
+    return 0;
+}
+
+/* Read `len` bytes from the pad at `offset` into `out` (must be mlock'd by
+ * caller). Returns 0 on success, non-zero on error. */
+static int read_pad_slice(uint64_t offset, size_t len, unsigned char *out) {
+    if (!g_otp_pad.pad_fp) return -1;
+    if (fseek(g_otp_pad.pad_fp, (long)offset, SEEK_SET) != 0) return -2;
+    size_t got = fread(out, 1, len, g_otp_pad.pad_fp);
+    if (got != len) return -3;
+    return 0;
+}
+
+/* ------------------------------------------------------------------ */
+/* Public encrypt/decrypt entrypoints (called by dispatcher verbs)   */
+/* ------------------------------------------------------------------ */
+
+/* OTPPAD_ENCRYPT_OK etc. are returned via *out_result. */
+
+/* Encrypt: takes plaintext bytes, returns malloc'd ASCII armor or binary blob.
+ *
+ * `encoding` is "ascii" or "binary".
+ * On success returns 0 and sets *out_payload (malloc'd, caller frees),
+ * *out_payload_len, and *out_new_offset.
+ */
+int otp_pad_encrypt(const unsigned char *plaintext, size_t pt_len,
+                    const char *encoding,
+                    char **out_payload, size_t *out_payload_len,
+                    uint64_t *out_new_offset) {
+    if (!g_otp_pad.bound) return 1;  /* not bound */
+    if (!plaintext || !out_payload || !out_payload_len || !out_new_offset) return 2;
+    *out_payload = NULL;
+    *out_payload_len = 0;
+
+    /* Pad the plaintext. */
+    size_t chunk = otppad_chunk_size(pt_len);
+    if (ensure_scratch(chunk) != 0) return 3;
+    unsigned char *buf = (unsigned char *)g_otp_pad.scratch_data;
+    memcpy(buf, plaintext, pt_len);
+    if (otppad_pad_apply(buf, pt_len, chunk) != 0) return 4;
+
+    /* Read current offset. */
+    uint64_t offset;
+    if (otppad_state_read(g_otp_pad.pads_dir, g_otp_pad.chksum, &offset) != 0) {
+        return 5;
+    }
+    if (offset + chunk > g_otp_pad.pad_size) {
+        return 6;  /* pad exhausted */
+    }
+
+    /* Read the pad slice into a second scratch buffer. */
+    /* Reuse the same scratch: read pad into second half, XOR in place.
+     * For simplicity, allocate a separate pad-slice buffer. */
+    unsigned char *pad_slice = (unsigned char *)malloc(chunk);
+    if (!pad_slice) return 7;
+    if (read_pad_slice(offset, chunk, pad_slice) != 0) {
+        free(pad_slice);
+        return 8;
+    }
+
+    /* XOR. */
+    for (size_t i = 0; i < chunk; i++) {
+        buf[i] ^= pad_slice[i];
+    }
+    secure_memzero(pad_slice, chunk);
+    free(pad_slice);
+
+    /* Advance offset atomically. */
+    uint64_t new_offset = offset + chunk;
+    if (otppad_state_write(g_otp_pad.pads_dir, g_otp_pad.chksum, new_offset) != 0) {
+        return 9;
+    }
+
+    /* Encode output. */
+    if (encoding && strcmp(encoding, "binary") == 0) {
+        /* Binary .otp: header + encrypted (padded) data. */
+        otppad_bin_header_t hdr;
+        memset(&hdr, 0, sizeof(hdr));
+        memcpy(hdr.magic, OTPPAD_MAGIC, OTPPAD_MAGIC_LEN);
+        hdr.version = OTPPAD_FORMAT_VERSION;
+        /* pad_chksum is binary 32 bytes — convert hex to bytes. */
+        for (int i = 0; i < OTPPAD_CHKSUM_BIN_LEN; i++) {
+            unsigned int byte;
+            sscanf(g_otp_pad.chksum + i * 2, "%02x", &byte);
+            hdr.pad_chksum[i] = (unsigned char)byte;
+        }
+        hdr.pad_offset = offset;
+        hdr.file_mode = 0644;
+        hdr.file_size = pt_len;  /* original (unpadded) size */
+
+        /* Build the blob in memory (avoid fmemopen — it can misbehave
+         * with NUL bytes on some platforms). */
+        size_t blob_size = 58 + chunk;
+        unsigned char *blob = (unsigned char *)malloc(blob_size);
+        if (!blob) return 10;
+        unsigned char *p = blob;
+        memcpy(p, OTPPAD_MAGIC, 4); p += 4;
+        memcpy(p, &hdr.version, 2); p += 2;
+        memcpy(p, hdr.pad_chksum, OTPPAD_CHKSUM_BIN_LEN); p += OTPPAD_CHKSUM_BIN_LEN;
+        memcpy(p, &hdr.pad_offset, 8); p += 8;
+        memcpy(p, &hdr.file_mode, 4); p += 4;
+        memcpy(p, &hdr.file_size, 8); p += 8;
+        /* p is now at byte 58. Copy the encrypted (padded) data. */
+        memcpy(p, buf, chunk);
+        *out_payload = (char *)blob;
+        *out_payload_len = blob_size;
+    } else {
+        /* ASCII armor. */
+        char *armor = NULL;
+        if (otppad_armor_generate(NSIGNER_OTP_VERSION, g_otp_pad.chksum, offset,
+                                  buf, chunk, &armor) != 0) {
+            return 14;
+        }
+        *out_payload = armor;
+        *out_payload_len = strlen(armor);
+    }
+
+    *out_new_offset = new_offset;
+    secure_memzero(g_otp_pad.scratch_data, g_otp_pad.scratch_size);
+    return 0;
+}
+
+/* Decrypt: takes ASCII armor or binary blob, returns malloc'd plaintext.
+ *
+ * `encoding` is "ascii" or "binary" (auto-detected if NULL).
+ * On success returns 0 and sets *out_plaintext (malloc'd, caller frees),
+ * *out_pt_len.
+ */
+int otp_pad_decrypt(const char *input, size_t input_len,
+                    const char *encoding,
+                    unsigned char **out_plaintext, size_t *out_pt_len) {
+    if (!g_otp_pad.bound) return 1;
+    if (!input || !out_plaintext || !out_pt_len) return 2;
+    *out_plaintext = NULL;
+    *out_pt_len = 0;
+
+    uint64_t offset;
+    size_t chunk;
+    unsigned char *ciphertext = NULL;
+    size_t ct_len = 0;
+
+    int is_binary;
+    if (encoding && strcmp(encoding, "binary") == 0) {
+        is_binary = 1;
+    } else if (encoding && strcmp(encoding, "ascii") == 0) {
+        is_binary = 0;
+    } else {
+        /* Auto-detect by magic bytes. */
+        is_binary = (input_len >= 4 && memcmp(input, OTPPAD_MAGIC, 4) == 0);
+    }
+
+    if (!is_binary) {
+        /* ASCII armor. */
+        char chksum[OTPPAD_CHKSUM_HEX_LEN + 1];
+        char b64[65536];
+        if (otppad_armor_parse(input, chksum, &offset, b64, sizeof(b64)) != 0) {
+            return 3;
+        }
+        if (strcmp(chksum, g_otp_pad.chksum) != 0) {
+            return 4;  /* pad mismatch */
+        }
+        int dlen = 0;
+        ciphertext = otppad_base64_decode(b64, &dlen);
+        if (!ciphertext) return 5;
+        ct_len = (size_t)dlen;
+        chunk = ct_len;
+    } else {
+        /* Binary .otp blob — parse directly from the buffer (avoid fmemopen
+         * which can misbehave with NUL bytes on some platforms). */
+        if (input_len < 58) return 6;
+        const unsigned char *p = (const unsigned char *)input;
+        otppad_bin_header_t hdr;
+        memset(&hdr, 0, sizeof(hdr));
+        memcpy(hdr.magic, p, 4); p += 4;
+        memcpy(&hdr.version, p, 2); p += 2;
+        memcpy(hdr.pad_chksum, p, OTPPAD_CHKSUM_BIN_LEN); p += OTPPAD_CHKSUM_BIN_LEN;
+        memcpy(&hdr.pad_offset, p, 8); p += 8;
+        memcpy(&hdr.file_mode, p, 4); p += 4;
+        memcpy(&hdr.file_size, p, 8); p += 8;
+        /* p is now at byte 58. */
+        if (memcmp(hdr.magic, OTPPAD_MAGIC, OTPPAD_MAGIC_LEN) != 0) {
+            return 8;
+        }
+        /* Convert binary chksum to hex for comparison. */
+        char chksum_hex[OTPPAD_CHKSUM_HEX_LEN + 1];
+        for (int i = 0; i < OTPPAD_CHKSUM_BIN_LEN; i++) {
+            sprintf(chksum_hex + i * 2, "%02x", hdr.pad_chksum[i]);
+        }
+        chksum_hex[OTPPAD_CHKSUM_HEX_LEN] = '\0';
+        if (strcmp(chksum_hex, g_otp_pad.chksum) != 0) {
+            return 9;
+        }
+        offset = hdr.pad_offset;
+        /* Remaining bytes after the 58-byte header are the ciphertext. */
+        ct_len = input_len - 58;
+        chunk = ct_len;
+        ciphertext = (unsigned char *)malloc(ct_len);
+        if (!ciphertext) return 10;
+        memcpy(ciphertext, p, ct_len);
+    }
+
+    if (ensure_scratch(chunk) != 0) {
+        free(ciphertext); return 12;
+    }
+    unsigned char *buf = (unsigned char *)g_otp_pad.scratch_data;
+
+    /* Read pad slice. */
+    unsigned char *pad_slice = (unsigned char *)malloc(chunk);
+    if (!pad_slice) { free(ciphertext); return 13; }
+    if (read_pad_slice(offset, chunk, pad_slice) != 0) {
+        free(pad_slice); free(ciphertext); return 14;
+    }
+
+    /* XOR (in-place into scratch). */
+    for (size_t i = 0; i < chunk; i++) {
+        buf[i] = ciphertext[i] ^ pad_slice[i];
+    }
+    secure_memzero(pad_slice, chunk);
+    free(pad_slice);
+    secure_memzero(ciphertext, ct_len);
+    free(ciphertext);
+
+    /* Strip padding. */
+    size_t pt_len;
+    if (otppad_pad_remove(buf, chunk, &pt_len) != 0) {
+        secure_memzero(g_otp_pad.scratch_data, g_otp_pad.scratch_size);
+        return 15;
+    }
+
+    /* Return plaintext. */
+    unsigned char *pt = (unsigned char *)malloc(pt_len ? pt_len : 1);
+    if (!pt) {
+        secure_memzero(g_otp_pad.scratch_data, g_otp_pad.scratch_size);
+        return 16;
+    }
+    memcpy(pt, buf, pt_len);
+    secure_memzero(g_otp_pad.scratch_data, g_otp_pad.scratch_size);
+
+    *out_plaintext = pt;
+    *out_pt_len = pt_len;
+    return 0;
+}
+
+/* ------------------------------------------------------------------ */
+/* Helpers for the dispatcher                                         */
+/* ------------------------------------------------------------------ */
+
+uint64_t otp_pad_current_offset(void) {
+    if (!g_otp_pad.bound) return 0;
+    uint64_t off;
+    if (otppad_state_read(g_otp_pad.pads_dir, g_otp_pad.chksum, &off) != 0) {
+        return 0;
+    }
+    return off;
+}
+
+uint64_t otp_pad_size(void) {
+    return g_otp_pad.bound ? g_otp_pad.pad_size : 0;
+}

src/otp_pad.h

@@ -0,0 +1,76 @@
+/*
+ * otp_pad.h — OTP pad state for n_signer (one pad per session).
+ *
+ * Bound at startup via otp_pad_bind(); accessed by the otp_encrypt /
+ * otp_decrypt dispatcher verbs. See plans/otp_nostr_integration.md.
+ */
+#ifndef NSIGNER_OTP_PAD_H
+#define NSIGNER_OTP_PAD_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Version string stamped into ASCII-armored output. */
+#define NSIGNER_OTP_VERSION "v0.0.2-otp"
+
+/* Returns 1 if a pad has been bound at startup, 0 otherwise. */
+int otp_pad_is_bound(void);
+
+/* Return the bound pad's 64-char hex checksum, or NULL if unbound. */
+const char *otp_pad_chksum(void);
+
+/* Return the bound pad's directory, or NULL if unbound. */
+const char *otp_pad_dir(void);
+
+/* Current offset (bytes consumed) of the bound pad, or 0 if unbound. */
+uint64_t otp_pad_current_offset(void);
+
+/* Total size in bytes of the bound pad, or 0 if unbound. */
+uint64_t otp_pad_size(void);
+
+/*
+ * Bind a pad at startup. Returns 0 on success, non-zero on error.
+ * `pads_dir` is the directory containing <chksum>.pad and <chksum>.state.
+ * `pad_spec` is a full 64-char chksum or a unique prefix.
+ * `allow_blkback` non-zero skips the blkback guard (for qvm-block testing).
+ */
+int otp_pad_bind(const char *pads_dir, const char *pad_spec, int allow_blkback);
+
+/* Unbind and zeroize all pad state. Idempotent. */
+void otp_pad_unbind(void);
+
+/*
+ * Encrypt plaintext bytes with the bound pad.
+ *
+ * `encoding` is "ascii" (default) or "binary".
+ * On success returns 0 and sets:
+ *   *out_payload     — malloc'd, caller frees (NUL-terminated for ascii)
+ *   *out_payload_len — length of payload
+ *   *out_new_offset  — pad offset after this encryption
+ */
+int otp_pad_encrypt(const unsigned char *plaintext, size_t pt_len,
+                    const char *encoding,
+                    char **out_payload, size_t *out_payload_len,
+                    uint64_t *out_new_offset);
+
+/*
+ * Decrypt a ciphertext (ASCII armor or binary .otp blob) with the bound pad.
+ *
+ * `encoding` is "ascii", "binary", or NULL (auto-detect by magic bytes).
+ * On success returns 0 and sets:
+ *   *out_plaintext — malloc'd, caller frees
+ *   *out_pt_len    — length of plaintext
+ */
+int otp_pad_decrypt(const char *input, size_t input_len,
+                    const char *encoding,
+                    unsigned char **out_plaintext, size_t *out_pt_len);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* NSIGNER_OTP_PAD_H */

src/policy.c

@@ -82,6 +82,8 @@ typedef enum {
     PURPOSE_SSH,
     PURPOSE_AGE,
     PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,      /* post-quantum signatures (ML-DSA, SLH-DSA) */
+    PURPOSE_PQ_KEM,      /* post-quantum key encapsulation (ML-KEM) */
     PURPOSE_UNKNOWN
 } role_purpose_t;
 
@@ -90,6 +92,9 @@ typedef enum {
     CURVE_SECP256K1 = 0,
     CURVE_ED25519,
     CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
     CURVE_UNKNOWN
 } role_curve_t;
 
@@ -195,6 +200,24 @@ const char *selector_strerror(int err);
 #define ENFORCE_ERR_PURPOSE      -1 /* purpose mismatch */
 #define ENFORCE_ERR_CURVE        -2 /* curve mismatch */
 #define ENFORCE_ERR_UNKNOWN_VERB -3 /* verb not recognized */
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
 
 /* Known verbs */
 #define VERB_SIGN_EVENT     "sign_event"
@@ -230,6 +253,8 @@ const char *enforce_strerror(int err);
 #define POLICY_MAX_PURPOSES   8
 #define POLICY_VERB_MAX_LEN   32
 #define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
 
 /* Prompt behavior */
 typedef enum {
@@ -254,6 +279,12 @@ typedef struct {
     int role_count;
     char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
     int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
     prompt_mode_t prompt;
     policy_source_t source;
 } policy_entry_t;
@@ -287,6 +318,20 @@ int policy_check(const policy_table_t *table, const char *caller_id,
                  const char *verb, const char *role_name, const char *purpose,
                  policy_source_t *out_source);
 
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
 /* Parse prompt mode from string */
 prompt_mode_t prompt_mode_from_str(const char *s);
 
@@ -294,15 +339,147 @@ prompt_mode_t prompt_mode_from_str(const char *s);
 const char *prompt_mode_to_str(prompt_mode_t m);
 
 
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,   /* existing, Nostr */
+    CRYPTO_ALG_ED25519,         /* new, SSH signatures */
+    CRYPTO_ALG_X25519,          /* new, key agreement */
+    CRYPTO_ALG_ML_DSA_65,       /* new, PQ signatures */
+    CRYPTO_ALG_SLH_DSA_128S,    /* new, PQ signatures */
+    CRYPTO_ALG_ML_KEM_768,      /* new, PQ KEM */
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;           /* 0 for KEM */
+    size_t ciphertext_len;    /* 0 for signatures */
+    size_t shared_secret_len; /* 0 for signatures */
+} crypto_alg_sizes_t;
+
+/* Get size info for an algorithm. Returns NULL for CRYPTO_ALG_UNKNOWN. */
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+
+/* Map role_curve_t + role_purpose_t to crypto_alg_t.
+ * Returns CRYPTO_ALG_UNKNOWN for unsupported combinations. */
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+
+/* Convert crypto_alg_t to string. Returns NULL for unknown. */
+const char *crypto_alg_to_str(crypto_alg_t alg);
+
+/* Parse string to crypto_alg_t. Returns CRYPTO_ALG_UNKNOWN for unrecognized. */
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+
+
 /* from crypto.h */
 
 
 /* Per-role derived key material (stored in secure memory) */
 typedef struct {
-    secure_buf_t private_key;  /* 32 bytes, mlock'd */
-    unsigned char public_key[32];
-    char pubkey_hex[65];       /* 64 hex chars + null */
-    char npub[128];            /* bech32 npub */
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
     int valid;
 } derived_key_t;
 
@@ -333,6 +510,82 @@ char *crypto_sign_event(const key_store_t *store, int role_index, const char *ev
 void crypto_wipe(key_store_t *store);
 
 
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
 /* from dispatcher.h */
 
 
@@ -341,10 +594,11 @@ typedef struct {
     role_table_t *role_table;
     mnemonic_state_t *mnemonic;
     key_store_t *key_store;
+    algorithm_key_cache_t *alg_key_cache;  /* algorithm-based on-demand keys */
 } dispatcher_ctx_t;
 
 /* Initialize dispatcher context */
-void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store);
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
 
 /*
  * Process a JSON-RPC request string and produce a JSON-RPC response string.
@@ -377,7 +631,7 @@ char *dispatcher_handle_request(dispatcher_ctx_t *ctx, const char *json_request)
 
 
 #define SERVER_SOCKET_NAME_MAX 108
-#define SERVER_MAX_MSG_SIZE    65536
+#define SERVER_MAX_MSG_SIZE    16777216
 
 /* Caller identity */
 typedef struct {
@@ -515,6 +769,22 @@ static int string_in_purposes(const char *needle, char haystack[][ROLE_PURPOSE_M
     return 0;
 }
 
+static int string_in_algorithms(const char *needle, char haystack[][32], int count) {
+    int i;
+
+    if (needle == NULL) {
+        return 0;
+    }
+
+    for (i = 0; i < count; ++i) {
+        if (strcmp(haystack[i], needle) == 0 || strcmp(haystack[i], "*") == 0) {
+            return 1;
+        }
+    }
+
+    return 0;
+}
+
 prompt_mode_t prompt_mode_from_str(const char *s) {
     if (s == NULL) {
         return PROMPT_DENY;
@@ -558,6 +828,12 @@ int parse_preapprove_spec(const char *spec, policy_entry_t *out_entry, int *out_
     int nostr_index = -1;
     int has_role = 0;
     int has_nostr_index = 0;
+    /* Algorithm-based fields */
+    int has_algorithm = 0;
+    int has_index = 0;
+    int alg_index_min = -1;
+    int alg_index_max = -1;
+    int verb_count = 0;
 
     if (out_nostr_index != NULL) {
         *out_nostr_index = -1;
@@ -603,6 +879,67 @@ int parse_preapprove_spec(const char *spec, policy_entry_t *out_entry, int *out_
             }
             nostr_index = (int)val;
             has_nostr_index = 1;
+        } else if (strcmp(token, "algorithm") == 0) {
+            /* algorithm=<name> — algorithm-based preapprove */
+            if (verb_count >= 0 && out_entry->alg_count < 16) {
+                strncpy(out_entry->algorithms[out_entry->alg_count], eq + 1, 31);
+                out_entry->algorithms[out_entry->alg_count][31] = '\0';
+                out_entry->alg_count++;
+            }
+            has_algorithm = 1;
+        } else if (strcmp(token, "index") == 0) {
+            /* index=<N> or index=<N-M> or index=* */
+            char *val = eq + 1;
+            if (strcmp(val, "*") == 0) {
+                alg_index_min = -1;
+                alg_index_max = -1;
+            } else {
+                char *dash = strchr(val, '-');
+                if (dash != NULL) {
+                    char *endptr = NULL;
+                    long lo, hi;
+                    *dash = '\0';
+                    errno = 0;
+                    lo = strtol(val, &endptr, 10);
+                    if (errno != 0 || endptr == val || *endptr != '\0' || lo < 0) {
+                        fprintf(stderr, "ERROR: --preapprove spec has invalid index= range: %s\n", spec);
+                        free(spec_copy);
+                        return -1;
+                    }
+                    errno = 0;
+                    hi = strtol(dash + 1, &endptr, 10);
+                    if (errno != 0 || endptr == dash + 1 || *endptr != '\0' || hi < lo) {
+                        fprintf(stderr, "ERROR: --preapprove spec has invalid index= range: %s\n", spec);
+                        free(spec_copy);
+                        return -1;
+                    }
+                    alg_index_min = (int)lo;
+                    alg_index_max = (int)hi;
+                } else {
+                    char *endptr = NULL;
+                    long val_num;
+                    errno = 0;
+                    val_num = strtol(val, &endptr, 10);
+                    if (errno != 0 || endptr == val || *endptr != '\0' || val_num < 0) {
+                        fprintf(stderr, "ERROR: --preapprove spec has invalid index= value: %s\n", spec);
+                        free(spec_copy);
+                        return -1;
+                    }
+                    alg_index_min = (int)val_num;
+                    alg_index_max = (int)val_num;
+                }
+            }
+    
+        } else if (strcmp(token, "verb") == 0) {
+            /* verb=<name> — can be repeated or comma-separated within the value.
+             * Since we split on commas already, each verb= is a single verb. */
+            if (verb_count < POLICY_MAX_VERBS) {
+                strncpy(out_entry->verbs[verb_count], eq + 1, POLICY_VERB_MAX_LEN - 1);
+                out_entry->verbs[verb_count][POLICY_VERB_MAX_LEN - 1] = '\0';
+                verb_count++;
+                out_entry->verb_count = verb_count;
+            }
+
         } else {
             fprintf(stderr, "ERROR: unknown --preapprove field '%s' in spec: %s\n", token, spec);
             free(spec_copy);
@@ -618,38 +955,99 @@ int parse_preapprove_spec(const char *spec, policy_entry_t *out_entry, int *out_
         return -1;
     }
 
-    if (!has_role && !has_nostr_index) {
-        fprintf(stderr, "ERROR: --preapprove spec must include 'role=' or 'nostr_index=': %s\n", spec);
+    /* Algorithm-based entries require algorithm= (index= and verb= optional).
+     * Role-based entries require role= or nostr_index=. The two forms are
+     * mutually exclusive. */
+    if (has_algorithm && (has_role || has_nostr_index)) {
+        fprintf(stderr, "ERROR: --preapprove spec has both algorithm= and role=/nostr_index= (use one form): %s\n", spec);
         free(spec_copy);
         return -1;
     }
 
-    if (has_role && has_nostr_index) {
+    if (!has_algorithm && !has_role && !has_nostr_index) {
+        fprintf(stderr, "ERROR: --preapprove spec must include 'algorithm=' or 'role=' or 'nostr_index=': %s\n", spec);
+        free(spec_copy);
+        return -1;
+    }
+
+    if (!has_algorithm && has_role && has_nostr_index) {
         fprintf(stderr, "ERROR: --preapprove spec has both 'role=' and 'nostr_index=' (use one): %s\n", spec);
         free(spec_copy);
         return -1;
     }
 
     memset(out_entry, 0, sizeof(*out_entry));
+    /* Re-set the algorithm/verb fields since memset cleared them. */
+    /* (We parsed into out_entry before the memset, so re-parse is needed.
+     * Actually we parsed algorithm/verb into out_entry directly above.
+     * The memset wiped them. Let's re-apply by re-parsing... but that's
+     * complex. Instead, save them before memset and restore after.) */
+
+    /* Save algorithm-based fields before memset. */
+    {
+        char saved_algs[16][32];
+        int saved_alg_count = 0;
+        char saved_verbs[POLICY_MAX_VERBS][POLICY_VERB_MAX_LEN];
+        int saved_verb_count = 0;
+        int si;
+
+        /* We already populated out_entry->algorithms and out_entry->verbs
+         * during parsing. Save them before the memset below. */
+        saved_alg_count = out_entry->alg_count;
+        for (si = 0; si < saved_alg_count; si++) {
+            memcpy(saved_algs[si], out_entry->algorithms[si], 32);
+        }
+        saved_verb_count = out_entry->verb_count;
+        for (si = 0; si < saved_verb_count; si++) {
+            memcpy(saved_verbs[si], out_entry->verbs[si], POLICY_VERB_MAX_LEN);
+        }
+
+        memset(out_entry, 0, sizeof(*out_entry));
+
+        /* Restore algorithm-based fields. */
+        out_entry->alg_count = saved_alg_count;
+        for (si = 0; si < saved_alg_count; si++) {
+            memcpy(out_entry->algorithms[si], saved_algs[si], 32);
+        }
+        out_entry->verb_count = saved_verb_count;
+        for (si = 0; si < saved_verb_count; si++) {
+            memcpy(out_entry->verbs[si], saved_verbs[si], POLICY_VERB_MAX_LEN);
+        }
+
+        /* Set index range. */
+        if (has_algorithm) {
+            out_entry->index_min = alg_index_min;
+            out_entry->index_max = alg_index_max;
+        } else {
+            out_entry->index_min = -1;
+            out_entry->index_max = -1;
+        }
+    }
+
     strncpy(out_entry->caller, caller, sizeof(out_entry->caller) - 1);
     out_entry->caller[sizeof(out_entry->caller) - 1] = '\0';
 
-    if (has_role) {
+    if (has_algorithm) {
+        /* Algorithm-based entry: no role needed. */
+        out_entry->role_count = 0;
+    } else if (has_role) {
         strncpy(out_entry->roles[0], role, sizeof(out_entry->roles[0]) - 1);
         out_entry->roles[0][sizeof(out_entry->roles[0]) - 1] = '\0';
+        out_entry->role_count = 1;
     } else {
+        /* nostr_index-based: map to role name. */
         if (nostr_index == 0) {
             strncpy(out_entry->roles[0], "main", sizeof(out_entry->roles[0]) - 1);
             out_entry->roles[0][sizeof(out_entry->roles[0]) - 1] = '\0';
         } else {
             (void)snprintf(out_entry->roles[0], sizeof(out_entry->roles[0]), "nostr_idx_%d", nostr_index);
         }
+        out_entry->role_count = 1;
         if (out_nostr_index != NULL) {
             *out_nostr_index = nostr_index;
         }
     }
 
-    out_entry->role_count = 1;
     out_entry->prompt = PROMPT_NEVER;
 
     free(spec_copy);
@@ -774,3 +1172,88 @@ int policy_check(const policy_table_t *table, const char *caller_id,
 
     return POLICY_NO_MATCH;
 }
+
+/* ---- Algorithm-based policy check ----
+ *
+ * policy_check_algorithm() checks whether a caller is allowed to invoke
+ * a verb with a given algorithm and index. Only entries with alg_count > 0
+ * (algorithm-based entries) are considered. Role-based entries are
+ * ignored here (they're handled by policy_check()).
+ *
+ * Matching criteria:
+ *   - caller matches (exact or "*")
+ *   - verb matches (or verb_count == 0 = any verb)
+ *   - algorithm matches (or alg_count == 0 = any algorithm, or "*" entry)
+ *   - index is within [index_min, index_max] (or index_min == -1 = any)
+ */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source) {
+    int i;
+
+    if (out_source != NULL) {
+        *out_source = POLICY_SOURCE_DEFAULT;
+    }
+
+    if (table == NULL || caller_id == NULL || verb == NULL || algorithm == NULL) {
+        return POLICY_NO_MATCH;
+    }
+
+    for (i = 0; i < table->count; ++i) {
+        const policy_entry_t *entry = &table->entries[i];
+        int caller_ok;
+        int verb_ok;
+        int alg_ok;
+        int index_ok;
+
+        /* Only consider algorithm-based entries. */
+        if (entry->alg_count == 0) {
+            continue;
+        }
+
+        caller_ok = (strcmp(entry->caller, "*") == 0) || (strcmp(entry->caller, caller_id) == 0);
+        if (!caller_ok) {
+            continue;
+        }
+
+        verb_ok = (entry->verb_count == 0) ||
+                  string_in_verbs(verb, (char (*)[POLICY_VERB_MAX_LEN])entry->verbs, entry->verb_count);
+        if (!verb_ok) {
+            continue;
+        }
+
+        alg_ok = string_in_algorithms(algorithm,
+                                        (char (*)[32])entry->algorithms, entry->alg_count);
+        if (!alg_ok) {
+            continue;
+        }
+
+        /* Index check: -1 means any index is allowed. */
+        if (entry->index_min < 0 || entry->index_max < 0) {
+            index_ok = 1;
+        } else {
+            index_ok = (index >= entry->index_min && index <= entry->index_max);
+        }
+        if (!index_ok) {
+            continue;
+        }
+
+        if (out_source != NULL) {
+            *out_source = entry->source;
+        }
+
+        if (entry->prompt == PROMPT_DENY) {
+            return POLICY_DENY;
+        }
+        if (entry->prompt == PROMPT_NEVER) {
+            return POLICY_ALLOW;
+        }
+
+        if (out_source != NULL) {
+            *out_source = POLICY_SOURCE_DEFAULT;
+        }
+        return POLICY_PROMPT;
+    }
+
+    return POLICY_NO_MATCH;
+}

src/pq_drbg.c

@@ -0,0 +1,134 @@
+/* pq_drbg.c — Deterministic PRNG for post-quantum key generation.
+ *
+ * Implements a SHAKE-256-based deterministic PRNG that replaces PQClean's
+ * randombytes() function. This allows deterministic PQ key generation from
+ * a mnemonic-derived seed: same seed → same randombytes output sequence.
+ *
+ * The PRNG is simple: SHAKE-256(seed || counter) produces a stream of
+ * pseudo-random bytes. The counter is a 64-bit little-endian integer that
+ * increments each time we need more output. This is not a NIST SP 800-90A
+ * compliant DRBG, but it is deterministic and sufficient for PQ keygen
+ * (which only needs the output to be uniformly distributed, which SHAKE
+ * provides).
+ *
+ * Security argument: SHAKE-256 is a XOF (extendable output function) based
+ * on Keccak. Given a 256-bit seed, the output is computationally
+ * indistinguishable from random. The counter prevents reuse of output
+ * blocks. This is the same approach used by PQM4 for deterministic test
+ * vectors.
+ */
+#include <string.h>
+#include <openssl/evp.h>
+
+/* --- DRBG state --- */
+
+static unsigned char g_seed[32];
+static int g_seed_len = 0;
+static uint64_t g_counter = 0;
+static unsigned char g_buffer[168]; /* SHAKE-256 rate = 136, but we use 168 for safety */
+static size_t g_buffer_pos = sizeof(g_buffer);
+static int g_initialized = 0;
+
+/* --- internal: squeeze more bytes from SHAKE-256 --- */
+
+static void drbg_refill(void) {
+    EVP_MD_CTX *ctx;
+    unsigned char seed_block[32 + 8]; /* seed + counter (8 bytes LE) */
+    size_t outlen = sizeof(g_buffer);
+
+    /* Build input: seed || counter (little-endian) */
+    memcpy(seed_block, g_seed, (size_t)g_seed_len);
+    seed_block[g_seed_len + 0] = (unsigned char)(g_counter & 0xFF);
+    seed_block[g_seed_len + 1] = (unsigned char)((g_counter >> 8) & 0xFF);
+    seed_block[g_seed_len + 2] = (unsigned char)((g_counter >> 16) & 0xFF);
+    seed_block[g_seed_len + 3] = (unsigned char)((g_counter >> 24) & 0xFF);
+    seed_block[g_seed_len + 4] = (unsigned char)((g_counter >> 32) & 0xFF);
+    seed_block[g_seed_len + 5] = (unsigned char)((g_counter >> 40) & 0xFF);
+    seed_block[g_seed_len + 6] = (unsigned char)((g_counter >> 48) & 0xFF);
+    seed_block[g_seed_len + 7] = (unsigned char)((g_counter >> 56) & 0xFF);
+
+    ctx = EVP_MD_CTX_new();
+    if (ctx == NULL) {
+        return;
+    }
+
+    if (EVP_DigestInit_ex(ctx, EVP_shake256(), NULL) != 1) {
+        EVP_MD_CTX_free(ctx);
+        return;
+    }
+    if (EVP_DigestUpdate(ctx, seed_block, (size_t)g_seed_len + 8) != 1) {
+        EVP_MD_CTX_free(ctx);
+        return;
+    }
+    if (EVP_DigestFinalXOF(ctx, g_buffer, outlen) != 1) {
+        EVP_MD_CTX_free(ctx);
+        return;
+    }
+
+    EVP_MD_CTX_free(ctx);
+
+    g_counter++;
+    g_buffer_pos = 0;
+}
+
+/* --- public API --- */
+
+void pq_drbg_init(const unsigned char *seed, size_t seed_len) {
+    if (seed == NULL || seed_len == 0) {
+        return;
+    }
+
+    /* Copy seed (up to 32 bytes; if shorter, zero-pad) */
+    memset(g_seed, 0, sizeof(g_seed));
+    if (seed_len > sizeof(g_seed)) {
+        seed_len = sizeof(g_seed);
+    }
+    memcpy(g_seed, seed, seed_len);
+    g_seed_len = (int)sizeof(g_seed); /* always use 32-byte seed (zero-padded) */
+
+    g_counter = 0;
+    g_buffer_pos = sizeof(g_buffer);
+    g_initialized = 1;
+}
+
+int pq_drbg_randombytes(unsigned char *buf, size_t len) {
+    if (buf == NULL || !g_initialized) {
+        return -1;
+    }
+
+    while (len > 0) {
+        size_t avail;
+        size_t to_copy;
+
+        if (g_buffer_pos >= sizeof(g_buffer)) {
+            drbg_refill();
+            if (g_buffer_pos >= sizeof(g_buffer)) {
+                return -1; /* refill failed */
+            }
+        }
+
+        avail = sizeof(g_buffer) - g_buffer_pos;
+        to_copy = (len < avail) ? len : avail;
+        memcpy(buf, g_buffer + g_buffer_pos, to_copy);
+        g_buffer_pos += to_copy;
+        buf += to_copy;
+        len -= to_copy;
+    }
+
+    return 0;
+}
+
+void pq_drbg_zeroize(void) {
+    memset(g_seed, 0, sizeof(g_seed));
+    memset(g_buffer, 0, sizeof(g_buffer));
+    g_seed_len = 0;
+    g_counter = 0;
+    g_buffer_pos = sizeof(g_buffer);
+    g_initialized = 0;
+}
+
+/* --- randombytes() — the function PQClean calls --- */
+
+int randombytes(unsigned char *buf, size_t len) {
+    return pq_drbg_randombytes(buf, len);
+}

src/role_table.c

@@ -82,6 +82,8 @@ typedef enum {
     PURPOSE_SSH,
     PURPOSE_AGE,
     PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,      /* post-quantum signatures (ML-DSA, SLH-DSA) */
+    PURPOSE_PQ_KEM,      /* post-quantum key encapsulation (ML-KEM) */
     PURPOSE_UNKNOWN
 } role_purpose_t;
 
@@ -90,6 +92,9 @@ typedef enum {
     CURVE_SECP256K1 = 0,
     CURVE_ED25519,
     CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
     CURVE_UNKNOWN
 } role_curve_t;
 
@@ -198,6 +203,24 @@ const char *selector_strerror(int err);
 #define ENFORCE_ERR_PURPOSE      -1 /* purpose mismatch */
 #define ENFORCE_ERR_CURVE        -2 /* curve mismatch */
 #define ENFORCE_ERR_UNKNOWN_VERB -3 /* verb not recognized */
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
 
 /* Known verbs */
 #define VERB_SIGN_EVENT     "sign_event"
@@ -233,6 +256,8 @@ const char *enforce_strerror(int err);
 #define POLICY_MAX_PURPOSES   8
 #define POLICY_VERB_MAX_LEN   32
 #define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
 
 /* Prompt behavior */
 typedef enum {
@@ -257,6 +282,12 @@ typedef struct {
     int role_count;
     char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
     int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
     prompt_mode_t prompt;
     policy_source_t source;
 } policy_entry_t;
@@ -290,6 +321,20 @@ int policy_check(const policy_table_t *table, const char *caller_id,
                  const char *verb, const char *role_name, const char *purpose,
                  policy_source_t *out_source);
 
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
 /* Parse prompt mode from string */
 prompt_mode_t prompt_mode_from_str(const char *s);
 
@@ -297,15 +342,147 @@ prompt_mode_t prompt_mode_from_str(const char *s);
 const char *prompt_mode_to_str(prompt_mode_t m);
 
 
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,   /* existing, Nostr */
+    CRYPTO_ALG_ED25519,         /* new, SSH signatures */
+    CRYPTO_ALG_X25519,          /* new, key agreement */
+    CRYPTO_ALG_ML_DSA_65,       /* new, PQ signatures */
+    CRYPTO_ALG_SLH_DSA_128S,    /* new, PQ signatures */
+    CRYPTO_ALG_ML_KEM_768,      /* new, PQ KEM */
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;           /* 0 for KEM */
+    size_t ciphertext_len;    /* 0 for signatures */
+    size_t shared_secret_len; /* 0 for signatures */
+} crypto_alg_sizes_t;
+
+/* Get size info for an algorithm. Returns NULL for CRYPTO_ALG_UNKNOWN. */
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+
+/* Map role_curve_t + role_purpose_t to crypto_alg_t.
+ * Returns CRYPTO_ALG_UNKNOWN for unsupported combinations. */
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+
+/* Convert crypto_alg_t to string. Returns NULL for unknown. */
+const char *crypto_alg_to_str(crypto_alg_t alg);
+
+/* Parse string to crypto_alg_t. Returns CRYPTO_ALG_UNKNOWN for unrecognized. */
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+
+
 /* from crypto.h */
 
 
 /* Per-role derived key material (stored in secure memory) */
 typedef struct {
-    secure_buf_t private_key;  /* 32 bytes, mlock'd */
-    unsigned char public_key[32];
-    char pubkey_hex[65];       /* 64 hex chars + null */
-    char npub[128];            /* bech32 npub */
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
     int valid;
 } derived_key_t;
 
@@ -336,6 +513,82 @@ char *crypto_sign_event(const key_store_t *store, int role_index, const char *ev
 void crypto_wipe(key_store_t *store);
 
 
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
 /* from dispatcher.h */
 
 
@@ -344,10 +597,11 @@ typedef struct {
     role_table_t *role_table;
     mnemonic_state_t *mnemonic;
     key_store_t *key_store;
+    algorithm_key_cache_t *alg_key_cache;  /* algorithm-based on-demand keys */
 } dispatcher_ctx_t;
 
 /* Initialize dispatcher context */
-void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store);
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
 
 /*
  * Process a JSON-RPC request string and produce a JSON-RPC response string.
@@ -380,7 +634,7 @@ char *dispatcher_handle_request(dispatcher_ctx_t *ctx, const char *json_request)
 
 
 #define SERVER_SOCKET_NAME_MAX 108
-#define SERVER_MAX_MSG_SIZE    65536
+#define SERVER_MAX_MSG_SIZE    16777216
 
 /* Caller identity */
 typedef struct {
@@ -591,6 +845,12 @@ role_purpose_t role_purpose_from_str(const char *s) {
     if (str_eq(s, "fips")) {
         return PURPOSE_FIPS;
     }
+    if (str_eq(s, "pq-sig")) {
+        return PURPOSE_PQ_SIG;
+    }
+    if (str_eq(s, "pq-kem")) {
+        return PURPOSE_PQ_KEM;
+    }
     return PURPOSE_UNKNOWN;
 }
 
@@ -604,6 +864,15 @@ role_curve_t role_curve_from_str(const char *s) {
     if (str_eq(s, "x25519")) {
         return CURVE_X25519;
     }
+    if (str_eq(s, "ml-dsa-65")) {
+        return CURVE_ML_DSA_65;
+    }
+    if (str_eq(s, "slh-dsa-128s")) {
+        return CURVE_SLH_DSA_128S;
+    }
+    if (str_eq(s, "ml-kem-768")) {
+        return CURVE_ML_KEM_768;
+    }
     return CURVE_UNKNOWN;
 }
 
@@ -619,6 +888,10 @@ const char *role_purpose_to_str(role_purpose_t p) {
             return "age";
         case PURPOSE_FIPS:
             return "fips";
+        case PURPOSE_PQ_SIG:
+            return "pq-sig";
+        case PURPOSE_PQ_KEM:
+            return "pq-kem";
         case PURPOSE_UNKNOWN:
         default:
             return "unknown";
@@ -633,6 +906,12 @@ const char *role_curve_to_str(role_curve_t c) {
             return "ed25519";
         case CURVE_X25519:
             return "x25519";
+        case CURVE_ML_DSA_65:
+            return "ml-dsa-65";
+        case CURVE_SLH_DSA_128S:
+            return "slh-dsa-128s";
+        case CURVE_ML_KEM_768:
+            return "ml-kem-768";
         case CURVE_UNKNOWN:
         default:
             return "unknown";

src/secure_mem.c

@@ -84,6 +84,8 @@ typedef enum {
     PURPOSE_SSH,
     PURPOSE_AGE,
     PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,      /* post-quantum signatures (ML-DSA, SLH-DSA) */
+    PURPOSE_PQ_KEM,      /* post-quantum key encapsulation (ML-KEM) */
     PURPOSE_UNKNOWN
 } role_purpose_t;
 
@@ -92,6 +94,9 @@ typedef enum {
     CURVE_SECP256K1 = 0,
     CURVE_ED25519,
     CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
     CURVE_UNKNOWN
 } role_curve_t;
 
@@ -197,6 +202,24 @@ const char *selector_strerror(int err);
 #define ENFORCE_ERR_PURPOSE      -1 /* purpose mismatch */
 #define ENFORCE_ERR_CURVE        -2 /* curve mismatch */
 #define ENFORCE_ERR_UNKNOWN_VERB -3 /* verb not recognized */
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
 
 /* Known verbs */
 #define VERB_SIGN_EVENT     "sign_event"
@@ -232,6 +255,8 @@ const char *enforce_strerror(int err);
 #define POLICY_MAX_PURPOSES   8
 #define POLICY_VERB_MAX_LEN   32
 #define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
 
 /* Prompt behavior */
 typedef enum {
@@ -256,6 +281,12 @@ typedef struct {
     int role_count;
     char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
     int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
     prompt_mode_t prompt;
     policy_source_t source;
 } policy_entry_t;
@@ -289,6 +320,20 @@ int policy_check(const policy_table_t *table, const char *caller_id,
                  const char *verb, const char *role_name, const char *purpose,
                  policy_source_t *out_source);
 
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
 /* Parse prompt mode from string */
 prompt_mode_t prompt_mode_from_str(const char *s);
 
@@ -296,15 +341,147 @@ prompt_mode_t prompt_mode_from_str(const char *s);
 const char *prompt_mode_to_str(prompt_mode_t m);
 
 
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,   /* existing, Nostr */
+    CRYPTO_ALG_ED25519,         /* new, SSH signatures */
+    CRYPTO_ALG_X25519,          /* new, key agreement */
+    CRYPTO_ALG_ML_DSA_65,       /* new, PQ signatures */
+    CRYPTO_ALG_SLH_DSA_128S,    /* new, PQ signatures */
+    CRYPTO_ALG_ML_KEM_768,      /* new, PQ KEM */
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;           /* 0 for KEM */
+    size_t ciphertext_len;    /* 0 for signatures */
+    size_t shared_secret_len; /* 0 for signatures */
+} crypto_alg_sizes_t;
+
+/* Get size info for an algorithm. Returns NULL for CRYPTO_ALG_UNKNOWN. */
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+
+/* Map role_curve_t + role_purpose_t to crypto_alg_t.
+ * Returns CRYPTO_ALG_UNKNOWN for unsupported combinations. */
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+
+/* Convert crypto_alg_t to string. Returns NULL for unknown. */
+const char *crypto_alg_to_str(crypto_alg_t alg);
+
+/* Parse string to crypto_alg_t. Returns CRYPTO_ALG_UNKNOWN for unrecognized. */
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+
+
 /* from crypto.h */
 
 
 /* Per-role derived key material (stored in secure memory) */
 typedef struct {
-    secure_buf_t private_key;  /* 32 bytes, mlock'd */
-    unsigned char public_key[32];
-    char pubkey_hex[65];       /* 64 hex chars + null */
-    char npub[128];            /* bech32 npub */
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
     int valid;
 } derived_key_t;
 
@@ -335,6 +512,82 @@ char *crypto_sign_event(const key_store_t *store, int role_index, const char *ev
 void crypto_wipe(key_store_t *store);
 
 
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
 /* from dispatcher.h */
 
 
@@ -343,10 +596,11 @@ typedef struct {
     role_table_t *role_table;
     mnemonic_state_t *mnemonic;
     key_store_t *key_store;
+    algorithm_key_cache_t *alg_key_cache;  /* algorithm-based on-demand keys */
 } dispatcher_ctx_t;
 
 /* Initialize dispatcher context */
-void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store);
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
 
 /*
  * Process a JSON-RPC request string and produce a JSON-RPC response string.
@@ -379,7 +633,7 @@ char *dispatcher_handle_request(dispatcher_ctx_t *ctx, const char *json_request)
 
 
 #define SERVER_SOCKET_NAME_MAX 108
-#define SERVER_MAX_MSG_SIZE    65536
+#define SERVER_MAX_MSG_SIZE    16777216
 
 /* Caller identity */
 typedef struct {

src/selector.c

@@ -82,6 +82,8 @@ typedef enum {
     PURPOSE_SSH,
     PURPOSE_AGE,
     PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,      /* post-quantum signatures (ML-DSA, SLH-DSA) */
+    PURPOSE_PQ_KEM,      /* post-quantum key encapsulation (ML-KEM) */
     PURPOSE_UNKNOWN
 } role_purpose_t;
 
@@ -90,6 +92,9 @@ typedef enum {
     CURVE_SECP256K1 = 0,
     CURVE_ED25519,
     CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
     CURVE_UNKNOWN
 } role_curve_t;
 
@@ -195,6 +200,24 @@ const char *selector_strerror(int err);
 #define ENFORCE_ERR_PURPOSE      -1 /* purpose mismatch */
 #define ENFORCE_ERR_CURVE        -2 /* curve mismatch */
 #define ENFORCE_ERR_UNKNOWN_VERB -3 /* verb not recognized */
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
 
 /* Known verbs */
 #define VERB_SIGN_EVENT     "sign_event"
@@ -230,6 +253,8 @@ const char *enforce_strerror(int err);
 #define POLICY_MAX_PURPOSES   8
 #define POLICY_VERB_MAX_LEN   32
 #define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
 
 /* Prompt behavior */
 typedef enum {
@@ -254,6 +279,12 @@ typedef struct {
     int role_count;
     char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
     int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
     prompt_mode_t prompt;
     policy_source_t source;
 } policy_entry_t;
@@ -287,6 +318,20 @@ int policy_check(const policy_table_t *table, const char *caller_id,
                  const char *verb, const char *role_name, const char *purpose,
                  policy_source_t *out_source);
 
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
 /* Parse prompt mode from string */
 prompt_mode_t prompt_mode_from_str(const char *s);
 
@@ -294,15 +339,147 @@ prompt_mode_t prompt_mode_from_str(const char *s);
 const char *prompt_mode_to_str(prompt_mode_t m);
 
 
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,   /* existing, Nostr */
+    CRYPTO_ALG_ED25519,         /* new, SSH signatures */
+    CRYPTO_ALG_X25519,          /* new, key agreement */
+    CRYPTO_ALG_ML_DSA_65,       /* new, PQ signatures */
+    CRYPTO_ALG_SLH_DSA_128S,    /* new, PQ signatures */
+    CRYPTO_ALG_ML_KEM_768,      /* new, PQ KEM */
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;           /* 0 for KEM */
+    size_t ciphertext_len;    /* 0 for signatures */
+    size_t shared_secret_len; /* 0 for signatures */
+} crypto_alg_sizes_t;
+
+/* Get size info for an algorithm. Returns NULL for CRYPTO_ALG_UNKNOWN. */
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+
+/* Map role_curve_t + role_purpose_t to crypto_alg_t.
+ * Returns CRYPTO_ALG_UNKNOWN for unsupported combinations. */
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+
+/* Convert crypto_alg_t to string. Returns NULL for unknown. */
+const char *crypto_alg_to_str(crypto_alg_t alg);
+
+/* Parse string to crypto_alg_t. Returns CRYPTO_ALG_UNKNOWN for unrecognized. */
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+
+
 /* from crypto.h */
 
 
 /* Per-role derived key material (stored in secure memory) */
 typedef struct {
-    secure_buf_t private_key;  /* 32 bytes, mlock'd */
-    unsigned char public_key[32];
-    char pubkey_hex[65];       /* 64 hex chars + null */
-    char npub[128];            /* bech32 npub */
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
     int valid;
 } derived_key_t;
 
@@ -333,6 +510,82 @@ char *crypto_sign_event(const key_store_t *store, int role_index, const char *ev
 void crypto_wipe(key_store_t *store);
 
 
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
 /* from dispatcher.h */
 
 
@@ -341,10 +594,11 @@ typedef struct {
     role_table_t *role_table;
     mnemonic_state_t *mnemonic;
     key_store_t *key_store;
+    algorithm_key_cache_t *alg_key_cache;  /* algorithm-based on-demand keys */
 } dispatcher_ctx_t;
 
 /* Initialize dispatcher context */
-void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store);
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
 
 /*
  * Process a JSON-RPC request string and produce a JSON-RPC response string.
@@ -377,7 +631,7 @@ char *dispatcher_handle_request(dispatcher_ctx_t *ctx, const char *json_request)
 
 
 #define SERVER_SOCKET_NAME_MAX 108
-#define SERVER_MAX_MSG_SIZE    65536
+#define SERVER_MAX_MSG_SIZE    16777216
 
 /* Caller identity */
 typedef struct {

src/server.c

@@ -5,6 +5,7 @@
 #include <stdint.h>
 #include <sys/types.h>
 #include <cJSON.h>
+#include "http_listener.h"
 
 /* from secure_mem.h */
 
@@ -84,6 +85,8 @@ typedef enum {
     PURPOSE_SSH,
     PURPOSE_AGE,
     PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,      /* post-quantum signatures (ML-DSA, SLH-DSA) */
+    PURPOSE_PQ_KEM,      /* post-quantum key encapsulation (ML-KEM) */
     PURPOSE_UNKNOWN
 } role_purpose_t;
 
@@ -92,6 +95,9 @@ typedef enum {
     CURVE_SECP256K1 = 0,
     CURVE_ED25519,
     CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
     CURVE_UNKNOWN
 } role_curve_t;
 
@@ -200,6 +206,24 @@ const char *selector_strerror(int err);
 #define ENFORCE_ERR_PURPOSE      -1 /* purpose mismatch */
 #define ENFORCE_ERR_CURVE        -2 /* curve mismatch */
 #define ENFORCE_ERR_UNKNOWN_VERB -3 /* verb not recognized */
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
 
 /* Known verbs */
 #define VERB_SIGN_EVENT     "sign_event"
@@ -235,6 +259,8 @@ const char *enforce_strerror(int err);
 #define POLICY_MAX_PURPOSES   8
 #define POLICY_VERB_MAX_LEN   32
 #define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
 
 /* Prompt behavior */
 typedef enum {
@@ -259,6 +285,12 @@ typedef struct {
     int role_count;
     char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
     int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
     prompt_mode_t prompt;
     policy_source_t source;
 } policy_entry_t;
@@ -297,6 +329,20 @@ int policy_check(const policy_table_t *table, const char *caller_id,
                  const char *verb, const char *role_name, const char *purpose,
                  policy_source_t *out_source);
 
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
 /* Parse prompt mode from string */
 prompt_mode_t prompt_mode_from_str(const char *s);
 
@@ -304,15 +350,147 @@ prompt_mode_t prompt_mode_from_str(const char *s);
 const char *prompt_mode_to_str(prompt_mode_t m);
 
 
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,   /* existing, Nostr */
+    CRYPTO_ALG_ED25519,         /* new, SSH signatures */
+    CRYPTO_ALG_X25519,          /* new, key agreement */
+    CRYPTO_ALG_ML_DSA_65,       /* new, PQ signatures */
+    CRYPTO_ALG_SLH_DSA_128S,    /* new, PQ signatures */
+    CRYPTO_ALG_ML_KEM_768,      /* new, PQ KEM */
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;           /* 0 for KEM */
+    size_t ciphertext_len;    /* 0 for signatures */
+    size_t shared_secret_len; /* 0 for signatures */
+} crypto_alg_sizes_t;
+
+/* Get size info for an algorithm. Returns NULL for CRYPTO_ALG_UNKNOWN. */
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+
+/* Map role_curve_t + role_purpose_t to crypto_alg_t.
+ * Returns CRYPTO_ALG_UNKNOWN for unsupported combinations. */
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+
+/* Convert crypto_alg_t to string. Returns NULL for unknown. */
+const char *crypto_alg_to_str(crypto_alg_t alg);
+
+/* Parse string to crypto_alg_t. Returns CRYPTO_ALG_UNKNOWN for unrecognized. */
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+
+
 /* from crypto.h */
 
 
 /* Per-role derived key material (stored in secure memory) */
 typedef struct {
-    secure_buf_t private_key;  /* 32 bytes, mlock'd */
-    unsigned char public_key[32];
-    char pubkey_hex[65];       /* 64 hex chars + null */
-    char npub[128];            /* bech32 npub */
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
     int valid;
 } derived_key_t;
 
@@ -346,6 +524,82 @@ char *crypto_sign_event(const key_store_t *store, int role_index, const char *ev
 void crypto_wipe(key_store_t *store);
 
 
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
 /* from dispatcher.h */
 
 
@@ -354,10 +608,11 @@ typedef struct {
     role_table_t *role_table;
     mnemonic_state_t *mnemonic;
     key_store_t *key_store;
+    algorithm_key_cache_t *alg_key_cache;  /* algorithm-based on-demand keys */
 } dispatcher_ctx_t;
 
 /* Initialize dispatcher context */
-void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store);
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
 
 /*
  * Process a JSON-RPC request string and produce a JSON-RPC response string.
@@ -390,12 +645,13 @@ char *dispatcher_handle_request(dispatcher_ctx_t *ctx, const char *json_request)
 
 
 #define SERVER_SOCKET_NAME_MAX 108
-#define SERVER_MAX_MSG_SIZE    65536
+#define SERVER_MAX_MSG_SIZE    16777216
 
 #define NSIGNER_LISTEN_UNIX   0
 #define NSIGNER_LISTEN_STDIO  1
 #define NSIGNER_LISTEN_QREXEC 2
 #define NSIGNER_LISTEN_TCP    3
+#define NSIGNER_LISTEN_HTTP   4
 
 #define NSIGNER_AUTH_OFF      0
 #define NSIGNER_AUTH_OPTIONAL 1
@@ -415,6 +671,9 @@ typedef struct {
 } caller_identity_t;
 
 /* Server context */
+#define INDEX_WHITELIST_MAX 256  /* nostr_index range 0-255 */
+#define INDEX_WHITELIST_BITMAP_SIZE (INDEX_WHITELIST_MAX / 8)  /* 32 bytes */
+
 typedef struct {
     char socket_name[SERVER_SOCKET_NAME_MAX]; /* abstract namespace name (without \0 prefix) */
     char last_error[256];
@@ -428,6 +687,8 @@ typedef struct {
     int auth_mode;
     int auth_skew_seconds;
     int bridge_source_trusted;  /* when set, unix connections send a qrexec_source preamble */
+    int index_whitelist_active;  /* 1 if index whitelist is set (not "all") */
+    unsigned char index_whitelist[INDEX_WHITELIST_BITMAP_SIZE];  /* bitmap of allowed nostr_index values */
 } server_ctx_t;
 
 /* Initialize server context. socket_name is the abstract namespace name (e.g. "nsigner").
@@ -444,6 +705,15 @@ void server_init(server_ctx_t *ctx, const char *socket_name, int socket_name_exp
  * identity is composed as qubes:<vm>. */
 void server_set_bridge_source_trusted(server_ctx_t *ctx, int enabled);
 
+/* Set the nostr_index whitelist from a parsed spec string.
+ * Spec format: "all" (no restriction), or comma-separated list of
+ * indices and ranges, e.g. "1,3,4" or "0-3" or "0-3,7,9".
+ * Returns 0 on success, -1 on parse error. */
+int server_set_index_whitelist(server_ctx_t *ctx, const char *spec);
+
+/* Check if a nostr_index is in the whitelist. Returns 1 if allowed, 0 if not. */
+int server_index_whitelist_allows(const server_ctx_t *ctx, int nostr_index);
+
 /* Start listening. Returns 0 on success, -1 on error. */
 int server_start(server_ctx_t *ctx);
 
@@ -514,6 +784,7 @@ int transport_recv_framed(int fd, char **out_payload, size_t max_size);
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <pthread.h>
 #include <sys/socket.h>
 #include <sys/un.h>
 #include <unistd.h>
@@ -1058,6 +1329,8 @@ void server_init(server_ctx_t *ctx, const char *socket_name, int socket_name_exp
     ctx->auth_mode = auth_mode;
     ctx->auth_skew_seconds = (auth_skew_seconds > 0) ? auth_skew_seconds : AUTH_DEFAULT_SKEW_SECONDS;
     ctx->bridge_source_trusted = 0;
+    ctx->index_whitelist_active = 0;
+    memset(ctx->index_whitelist, 0, sizeof(ctx->index_whitelist));
     if (!g_auth_nonce_cache_inited) {
         auth_nonce_cache_init(&g_auth_nonce_cache);
         g_auth_nonce_cache_inited = 1;
@@ -1071,6 +1344,87 @@ void server_set_bridge_source_trusted(server_ctx_t *ctx, int enabled) {
     ctx->bridge_source_trusted = enabled ? 1 : 0;
 }
 
+static void whitelist_set_bit(unsigned char *bitmap, int index) {
+    if (index >= 0 && index < INDEX_WHITELIST_MAX) {
+        bitmap[index / 8] |= (1 << (index % 8));
+    }
+}
+
+static int whitelist_get_bit(const unsigned char *bitmap, int index) {
+    if (index < 0 || index >= INDEX_WHITELIST_MAX) {
+        return 0;
+    }
+    return (bitmap[index / 8] >> (index % 8)) & 1;
+}
+
+int server_set_index_whitelist(server_ctx_t *ctx, const char *spec) {
+    char buf[256];
+    char *p;
+    char *token;
+
+    if (ctx == NULL || spec == NULL) {
+        return -1;
+    }
+
+    /* "all" means no restriction */
+    if (strcmp(spec, "all") == 0) {
+        ctx->index_whitelist_active = 0;
+        memset(ctx->index_whitelist, 0, sizeof(ctx->index_whitelist));
+        return 0;
+    }
+
+    strncpy(buf, spec, sizeof(buf) - 1);
+    buf[sizeof(buf) - 1] = '\0';
+
+    /* Parse comma-separated entries: "1,3,4" or "0-3" or "0-3,7,9" */
+    memset(ctx->index_whitelist, 0, sizeof(ctx->index_whitelist));
+    p = buf;
+    while (p != NULL && *p != '\0') {
+        char *comma = strchr(p, ',');
+        if (comma != NULL) {
+            *comma = '\0';
+        }
+
+        /* Parse token: either "N" or "N-M" (range) */
+        char *dash = strchr(p, '-');
+        if (dash != NULL) {
+            *dash = '\0';
+            char *endptr1 = NULL, *endptr2 = NULL;
+            long lo = strtol(p, &endptr1, 10);
+            long hi = strtol(dash + 1, &endptr2, 10);
+            if (*endptr1 != '\0' || *endptr2 != '\0' || lo < 0 || hi < 0 ||
+                lo >= INDEX_WHITELIST_MAX || hi >= INDEX_WHITELIST_MAX || lo > hi) {
+                return -1;
+            }
+            for (long i = lo; i <= hi; i++) {
+                whitelist_set_bit(ctx->index_whitelist, (int)i);
+            }
+        } else {
+            char *endptr = NULL;
+            long idx = strtol(p, &endptr, 10);
+            if (*endptr != '\0' || idx < 0 || idx >= INDEX_WHITELIST_MAX) {
+                return -1;
+            }
+            whitelist_set_bit(ctx->index_whitelist, (int)idx);
+        }
+
+        p = (comma != NULL) ? comma + 1 : NULL;
+    }
+
+    ctx->index_whitelist_active = 1;
+    return 0;
+}
+
+int server_index_whitelist_allows(const server_ctx_t *ctx, int nostr_index) {
+    if (ctx == NULL) {
+        return 1;  /* no ctx = allow (shouldn't happen) */
+    }
+    if (!ctx->index_whitelist_active) {
+        return 1;  /* "all" mode = no restriction */
+    }
+    return whitelist_get_bit(ctx->index_whitelist, nostr_index);
+}
+
 int server_start(server_ctx_t *ctx) {
     int fd;
     struct sockaddr_un addr;
@@ -1097,13 +1451,23 @@ int server_start(server_ctx_t *ctx) {
         return 0;
     }
 
-    if (ctx->listen_mode == NSIGNER_LISTEN_TCP) {
+    if (ctx->listen_mode == NSIGNER_LISTEN_TCP ||
+        ctx->listen_mode == NSIGNER_LISTEN_HTTP) {
         int family;
         uint16_t port;
         char host[64];
         int one = 1;
 
-        int prc = parse_tcp_target(ctx->socket_name, &family, host, sizeof(host), &port);
+        /* HTTP mode uses the same TCP socket setup, just with an "http:" prefix
+         * instead of "tcp:". Convert to tcp: for parse_tcp_target. */
+        char tcp_target[128];
+        if (ctx->listen_mode == NSIGNER_LISTEN_HTTP) {
+            snprintf(tcp_target, sizeof(tcp_target), "tcp:%s", ctx->socket_name + 5);
+        } else {
+            snprintf(tcp_target, sizeof(tcp_target), "%s", ctx->socket_name);
+        }
+
+        int prc = parse_tcp_target(tcp_target, &family, host, sizeof(host), &port);
         if (prc != 0) {
             (void)snprintf(ctx->last_error,
                            sizeof(ctx->last_error),
@@ -1353,6 +1717,33 @@ int server_get_caller(int fd, caller_identity_t *out) {
     return 0;
 }
 
+/* ---- Async mine_event support ---- */
+
+typedef struct {
+    int client_fd;
+    int is_stdio;
+    dispatcher_ctx_t *dispatcher;
+    char *request;
+} mine_thread_arg_t;
+
+static void *mine_event_thread(void *arg) {
+    mine_thread_arg_t *a = (mine_thread_arg_t *)arg;
+    char *response = NULL;
+
+    response = dispatcher_handle_request(a->dispatcher, a->request);
+    if (response != NULL) {
+        (void)transport_send_framed(a->is_stdio ? STDOUT_FILENO : a->client_fd, response);
+        free(response);
+    }
+
+    free(a->request);
+    if (!a->is_stdio) {
+        close(a->client_fd);
+    }
+    free(a);
+    return NULL;
+}
+
 int server_handle_one(server_ctx_t *ctx, server_activity_cb cb, void *cb_data) {
     int client_fd;
     caller_identity_t caller;
@@ -1396,6 +1787,14 @@ int server_handle_one(server_ctx_t *ctx, server_activity_cb cb, void *cb_data) {
             }
             return -1;
         }
+        /* Set client fd to blocking mode (the listen socket is non-blocking,
+         * and accept() may inherit that flag on some platforms). */
+        {
+            int cflags = fcntl(client_fd, F_GETFL, 0);
+            if (cflags >= 0) {
+                (void)fcntl(client_fd, F_SETFL, cflags & ~O_NONBLOCK);
+            }
+        }
     }
 
     if (server_get_caller(client_fd, &caller) != 0) {
@@ -1405,6 +1804,12 @@ int server_handle_one(server_ctx_t *ctx, server_activity_cb cb, void *cb_data) {
         return -1;
     }
 
+    /* HTTP mode: override caller kind so auth envelopes are not required
+     * (HTTP relies on localhost binding + policy/approval prompts). */
+    if (ctx->listen_mode == NSIGNER_LISTEN_HTTP) {
+        caller.kind = NSIGNER_LISTEN_HTTP;
+    }
+
     /*
      * Bridge-source-trusted path: when the unix listener is marked as a
      * trusted bridge socket (started with --bridge-source-trusted), each
@@ -1460,7 +1865,30 @@ int server_handle_one(server_ctx_t *ctx, server_activity_cb cb, void *cb_data) {
         cJSON_Delete(proot);
     }
 
-    if (transport_recv_framed(client_fd, &request, SERVER_MAX_MSG_SIZE) != 0) {
+    int is_http = (ctx->listen_mode == NSIGNER_LISTEN_HTTP);
+
+    if (is_http) {
+        /* HTTP mode: parse the HTTP request to get the JSON body. */
+        int http_rc = http_recv_request(client_fd, &request, SERVER_MAX_MSG_SIZE);
+        if (http_rc == 0 && request != NULL && request[0] == '\0') {
+            /* OPTIONS preflight — send CORS headers. */
+            (void)http_send_cors_preflight(client_fd);
+            free(request);
+            close(client_fd);
+            return 1;
+        }
+        if (http_rc != 0 || request == NULL) {
+            if (http_rc == -2) {
+                (void)http_send_error(client_fd, 405, "method_not_allowed");
+            } else if (http_rc == -4) {
+                (void)http_send_error(client_fd, 413, "payload_too_large");
+            } else {
+                (void)http_send_error(client_fd, 400, "bad_request");
+            }
+            if (client_fd != STDIN_FILENO) close(client_fd);
+            return 1;
+        }
+    } else if (transport_recv_framed(client_fd, &request, SERVER_MAX_MSG_SIZE) != 0) {
         response = strdup("{\"id\":\"null\",\"error\":{\"code\":-32700,\"message\":\"parse_error\"}}");
         if (response != NULL) {
             (void)transport_send_framed((client_fd == STDIN_FILENO) ? STDOUT_FILENO : client_fd, response);
@@ -1520,7 +1948,11 @@ int server_handle_one(server_ctx_t *ctx, server_activity_cb cb, void *cb_data) {
                     response = strdup(errbuf);
                 }
                 if (response != NULL) {
+                    if (is_http) {
+                        (void)http_send_response(client_fd, response);
+                    } else {
                         (void)transport_send_framed((client_fd == STDIN_FILENO) ? STDOUT_FILENO : client_fd, response);
+                    }
                     free(response);
                 }
                 free(request);
@@ -1569,6 +2001,24 @@ int server_handle_one(server_ctx_t *ctx, server_activity_cb cb, void *cb_data) {
         }
     }
 
+    /*
+     * Index whitelist enforcement: if the request specifies a nostr_index
+     * and the whitelist is active (not "all"), check that the index is
+     * allowed. This is a hard deny — it happens before policy/approval,
+     * so even an approved caller cannot access a non-whitelisted index.
+     * We set hard_selector_error to a sentinel so the policy_check branch
+     * is skipped.
+     */
+    if (hard_selector_error == 0 && selector_req.has_nostr_index &&
+        !server_index_whitelist_allows(ctx, selector_req.nostr_index)) {
+        (void)snprintf(role_name, sizeof(role_name), "nostr_idx_%d", selector_req.nostr_index);
+        response = strdup("{\"id\":\"null\",\"error\":{\"code\":2002,\"message\":\"index_not_allowed\"}}");
+        pchk = POLICY_DENY;
+        verdict = "DENIED";
+        source_label = "index-not-approved";
+        hard_selector_error = -100;  /* sentinel: skip policy_check */
+    }
+
     if (hard_selector_error == SELECTOR_ERR_AMBIGUOUS) {
         response = strdup("{\"id\":\"null\",\"error\":{\"code\":1001,\"message\":\"ambiguous_role_selector\"}}");
         pchk = POLICY_DENY;
@@ -1578,9 +2028,11 @@ int server_handle_one(server_ctx_t *ctx, server_activity_cb cb, void *cb_data) {
     } else if (hard_selector_error == SELECTOR_ERR_NOT_FOUND) {
         response = strdup("{\"id\":\"null\",\"error\":{\"code\":1002,\"message\":\"unknown_role\"}}");
         pchk = POLICY_DENY;
-    } else {
+    } else if (hard_selector_error == 0) {
+        /* Normal path: run policy_check (skip if whitelist already denied) */
         pchk = policy_check(ctx->policy, caller.caller_id, method, role_name, purpose, &policy_src);
     }
+    /* else: hard_selector_error == -100 (whitelist deny) — keep pchk=POLICY_DENY */
 
     if (pchk == POLICY_PROMPT) {
         pchk = prompt_for_policy_decision(&caller, method, role_name, purpose, pending_derivation);
@@ -1636,6 +2088,47 @@ int server_handle_one(server_ctx_t *ctx, server_activity_cb cb, void *cb_data) {
     }
 
     if (pchk == POLICY_ALLOW && !derivation_error) {
+        /*
+         * mine_event is a long-running operation (potentially seconds to minutes).
+         * Spawn a detached thread so the server stays responsive. The thread
+         * owns the client_fd and request, and sends the response when mining
+         * completes. We skip the synchronous response path below.
+         */
+        if (strcmp(method, "mine_event") == 0 && client_fd != STDIN_FILENO) {
+            mine_thread_arg_t *marg = malloc(sizeof(mine_thread_arg_t));
+            if (marg != NULL) {
+                pthread_t mine_tid;
+
+                marg->client_fd = client_fd;
+                marg->is_stdio = 0;
+                marg->dispatcher = ctx->dispatcher;
+                marg->request = request;
+
+                if (pthread_create(&mine_tid, NULL, mine_event_thread, marg) == 0) {
+                    pthread_detach(mine_tid);
+                    /* Thread owns client_fd and request — prevent cleanup below */
+                    request = NULL;
+                    response = NULL;
+                    verdict = "ALLOWED";
+                    source_label = "async-mine";
+                    (void)snprintf(activity,
+                                   sizeof(activity),
+                                   "%s %s(%s) %s:%s",
+                                   caller.caller_id,
+                                   method,
+                                   role_name,
+                                   "ALLOWED",
+                                   "async-mine");
+                    if (cb != NULL) {
+                        cb(activity, cb_data);
+                    }
+                    return 1;
+                }
+                /* pthread_create failed — fall through to synchronous path */
+                free(marg);
+            }
+        }
+
         verdict = "ALLOWED";
         response = dispatcher_handle_request(ctx->dispatcher, request);
         if (response == NULL) {
@@ -1652,8 +2145,12 @@ int server_handle_one(server_ctx_t *ctx, server_activity_cb cb, void *cb_data) {
     }
 
     if (response != NULL) {
+        if (is_http) {
+            (void)http_send_response(client_fd, response);
+        } else {
             (void)transport_send_framed((client_fd == STDIN_FILENO) ? STDOUT_FILENO : client_fd, response);
         }
+    }
 
     if (pchk == POLICY_ALLOW && policy_src == POLICY_SOURCE_PREAPPROVE) {
         source_label = "preapprove";
@@ -1661,6 +2158,9 @@ int server_handle_one(server_ctx_t *ctx, server_activity_cb cb, void *cb_data) {
         source_label = "session-grant";
     } else if (pchk == POLICY_ALLOW) {
         source_label = "prompt";
+    } else if (hard_selector_error == -100) {
+        /* Index whitelist denial — keep the label set by the whitelist check */
+        /* source_label already set to "index-not-approved" above */
     } else {
         source_label = "no-match";
     }
@@ -1692,7 +2192,9 @@ void server_stop(server_ctx_t *ctx) {
     }
 
     if (ctx->listen_fd >= 0) {
-        if (ctx->listen_mode == NSIGNER_LISTEN_UNIX || ctx->listen_mode == NSIGNER_LISTEN_TCP) {
+        if (ctx->listen_mode == NSIGNER_LISTEN_UNIX ||
+            ctx->listen_mode == NSIGNER_LISTEN_TCP ||
+            ctx->listen_mode == NSIGNER_LISTEN_HTTP) {
             close(ctx->listen_fd);
         }
         ctx->listen_fd = -1;

src/socket_name.c

@@ -84,6 +84,8 @@ typedef enum {
     PURPOSE_SSH,
     PURPOSE_AGE,
     PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,      /* post-quantum signatures (ML-DSA, SLH-DSA) */
+    PURPOSE_PQ_KEM,      /* post-quantum key encapsulation (ML-KEM) */
     PURPOSE_UNKNOWN
 } role_purpose_t;
 
@@ -92,6 +94,9 @@ typedef enum {
     CURVE_SECP256K1 = 0,
     CURVE_ED25519,
     CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
     CURVE_UNKNOWN
 } role_curve_t;
 
@@ -197,6 +202,24 @@ const char *selector_strerror(int err);
 #define ENFORCE_ERR_PURPOSE      -1 /* purpose mismatch */
 #define ENFORCE_ERR_CURVE        -2 /* curve mismatch */
 #define ENFORCE_ERR_UNKNOWN_VERB -3 /* verb not recognized */
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
 
 /* Known verbs */
 #define VERB_SIGN_EVENT     "sign_event"
@@ -232,6 +255,8 @@ const char *enforce_strerror(int err);
 #define POLICY_MAX_PURPOSES   8
 #define POLICY_VERB_MAX_LEN   32
 #define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
 
 /* Prompt behavior */
 typedef enum {
@@ -256,6 +281,12 @@ typedef struct {
     int role_count;
     char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
     int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
     prompt_mode_t prompt;
     policy_source_t source;
 } policy_entry_t;
@@ -289,6 +320,20 @@ int policy_check(const policy_table_t *table, const char *caller_id,
                  const char *verb, const char *role_name, const char *purpose,
                  policy_source_t *out_source);
 
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
 /* Parse prompt mode from string */
 prompt_mode_t prompt_mode_from_str(const char *s);
 
@@ -296,15 +341,147 @@ prompt_mode_t prompt_mode_from_str(const char *s);
 const char *prompt_mode_to_str(prompt_mode_t m);
 
 
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,   /* existing, Nostr */
+    CRYPTO_ALG_ED25519,         /* new, SSH signatures */
+    CRYPTO_ALG_X25519,          /* new, key agreement */
+    CRYPTO_ALG_ML_DSA_65,       /* new, PQ signatures */
+    CRYPTO_ALG_SLH_DSA_128S,    /* new, PQ signatures */
+    CRYPTO_ALG_ML_KEM_768,      /* new, PQ KEM */
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;           /* 0 for KEM */
+    size_t ciphertext_len;    /* 0 for signatures */
+    size_t shared_secret_len; /* 0 for signatures */
+} crypto_alg_sizes_t;
+
+/* Get size info for an algorithm. Returns NULL for CRYPTO_ALG_UNKNOWN. */
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+
+/* Map role_curve_t + role_purpose_t to crypto_alg_t.
+ * Returns CRYPTO_ALG_UNKNOWN for unsupported combinations. */
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+
+/* Convert crypto_alg_t to string. Returns NULL for unknown. */
+const char *crypto_alg_to_str(crypto_alg_t alg);
+
+/* Parse string to crypto_alg_t. Returns CRYPTO_ALG_UNKNOWN for unrecognized. */
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+
+
 /* from crypto.h */
 
 
 /* Per-role derived key material (stored in secure memory) */
 typedef struct {
-    secure_buf_t private_key;  /* 32 bytes, mlock'd */
-    unsigned char public_key[32];
-    char pubkey_hex[65];       /* 64 hex chars + null */
-    char npub[128];            /* bech32 npub */
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
     int valid;
 } derived_key_t;
 
@@ -335,6 +512,82 @@ char *crypto_sign_event(const key_store_t *store, int role_index, const char *ev
 void crypto_wipe(key_store_t *store);
 
 
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
 /* from dispatcher.h */
 
 
@@ -343,10 +596,11 @@ typedef struct {
     role_table_t *role_table;
     mnemonic_state_t *mnemonic;
     key_store_t *key_store;
+    algorithm_key_cache_t *alg_key_cache;  /* algorithm-based on-demand keys */
 } dispatcher_ctx_t;
 
 /* Initialize dispatcher context */
-void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store);
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
 
 /*
  * Process a JSON-RPC request string and produce a JSON-RPC response string.
@@ -379,7 +633,7 @@ char *dispatcher_handle_request(dispatcher_ctx_t *ctx, const char *json_request)
 
 
 #define SERVER_SOCKET_NAME_MAX 108
-#define SERVER_MAX_MSG_SIZE    65536
+#define SERVER_MAX_MSG_SIZE    16777216
 
 /* Caller identity */
 typedef struct {

tests/test_algorithm_api.c

@@ -0,0 +1,693 @@
+/* test_algorithm_api.c — Tests for the algorithm-based API.
+ *
+ * Tests the new verbs: sign, verify, encapsulate, decapsulate,
+ * derive_shared_secret, and the algorithm-based get_public_key.
+ * Also tests old verb aliases and enforcement.
+ */
+
+/* NSIGNER_HEADERLESS_DECLS_BEGIN */
+#include <stddef.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <cJSON.h>
+
+/* from secure_mem.h */
+typedef struct {
+    void *data;
+    size_t size;
+    int locked;
+} secure_buf_t;
+int secure_buf_alloc(secure_buf_t *buf, size_t size);
+void secure_buf_free(secure_buf_t *buf);
+void secure_memzero(void *ptr, size_t len);
+
+/* from mnemonic.h */
+#define MNEMONIC_MAX_LEN 256
+typedef struct {
+    secure_buf_t buf;
+    int loaded;
+    int word_count;
+} mnemonic_state_t;
+void mnemonic_init(mnemonic_state_t *state);
+int mnemonic_load(mnemonic_state_t *state, const char *phrase);
+void mnemonic_unload(mnemonic_state_t *state);
+int mnemonic_is_loaded(const mnemonic_state_t *state);
+const char *mnemonic_get_phrase(const mnemonic_state_t *state);
+
+/* from role_table.h */
+#define ROLE_NAME_MAX 64
+#define ROLE_PATH_MAX 128
+#define ROLE_PURPOSE_MAX 32
+#define ROLE_CURVE_MAX 16
+#define ROLE_PUBKEY_HEX_MAX 66
+#define ROLE_TABLE_MAX_ENTRIES 256
+typedef enum { PURPOSE_NOSTR=0, PURPOSE_BITCOIN, PURPOSE_SSH, PURPOSE_AGE, PURPOSE_FIPS, PURPOSE_PQ_SIG, PURPOSE_PQ_KEM, PURPOSE_UNKNOWN } role_purpose_t;
+typedef enum { CURVE_SECP256K1=0, CURVE_ED25519, CURVE_X25519, CURVE_ML_DSA_65, CURVE_SLH_DSA_128S, CURVE_ML_KEM_768, CURVE_UNKNOWN } role_curve_t;
+typedef enum { SELECTOR_NOSTR_INDEX, SELECTOR_ROLE_PATH } role_selector_type_t;
+typedef struct {
+    char name[ROLE_NAME_MAX];
+    char purpose_str[ROLE_PURPOSE_MAX];
+    char curve_str[ROLE_CURVE_MAX];
+    role_purpose_t purpose;
+    role_curve_t curve;
+    role_selector_type_t selector_type;
+    int nostr_index;
+    char role_path[ROLE_PATH_MAX];
+    char pubkey_hex[ROLE_PUBKEY_HEX_MAX];
+    int derived;
+} role_entry_t;
+typedef struct { role_entry_t entries[ROLE_TABLE_MAX_ENTRIES]; int count; } role_table_t;
+void role_table_init(role_table_t *table);
+int role_table_add(role_table_t *table, const role_entry_t *entry);
+role_entry_t *role_table_find_by_name(role_table_t *table, const char *name);
+role_purpose_t role_purpose_from_str(const char *s);
+role_curve_t role_curve_from_str(const char *s);
+
+/* from enforcement.h */
+#define ENFORCE_OK                0
+#define ENFORCE_ERR_PURPOSE      -1
+#define ENFORCE_ERR_CURVE        -2
+#define ENFORCE_ERR_UNKNOWN_VERB -3
+#define ENFORCE_ERR_ALGORITHM  -4
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+#define VERB_SIGN_EVENT     "sign_event"
+#define VERB_GET_PUBLIC_KEY "get_public_key"
+#define VERB_NIP44_ENCRYPT  "nip44_encrypt"
+#define VERB_NIP44_DECRYPT  "nip44_decrypt"
+#define VERB_NIP04_ENCRYPT  "nip04_encrypt"
+#define VERB_NIP04_DECRYPT  "nip04_decrypt"
+#define VERB_MINE_EVENT     "mine_event"
+#define VERB_SIGN_DATA      "sign_data"
+#define VERB_VERIFY_SIG     "verify_signature"
+#define VERB_SSH_SIGN       "ssh_sign"
+#define VERB_KEM_ENCAPS     "kem_encapsulate"
+#define VERB_KEM_DECAPS     "kem_decapsulate"
+int enforce_verb_role(const char *verb, const role_entry_t *role);
+const char *enforce_strerror(int err);
+
+/* from policy.h */
+#define POLICY_MAX_ENTRIES    32
+#define POLICY_MAX_VERBS      16
+#define POLICY_MAX_ROLES      16
+#define POLICY_MAX_PURPOSES   8
+#define POLICY_VERB_MAX_LEN   32
+#define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+typedef enum { PROMPT_NEVER=0, PROMPT_FIRST_PER_BOOT, PROMPT_EVERY_REQUEST, PROMPT_DENY } prompt_mode_t;
+typedef enum { POLICY_SOURCE_DEFAULT=0, POLICY_SOURCE_PREAPPROVE, POLICY_SOURCE_SESSION_GRANT } policy_source_t;
+typedef struct {
+    char caller[POLICY_CALLER_MAX_LEN];
+    char verbs[POLICY_MAX_VERBS][POLICY_VERB_MAX_LEN];
+    int verb_count;
+    char roles[POLICY_MAX_ROLES][ROLE_NAME_MAX];
+    int role_count;
+    char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
+    int purpose_count;
+    char algorithms[16][32];
+    int alg_count;
+    int index_min;
+    int index_max;
+    prompt_mode_t prompt;
+    policy_source_t source;
+} policy_entry_t;
+typedef struct { policy_entry_t entries[POLICY_MAX_ENTRIES]; int count; } policy_table_t;
+#define POLICY_ALLOW     0
+#define POLICY_DENY     -1
+#define POLICY_PROMPT   -2
+#define POLICY_NO_MATCH -3
+void policy_table_init(policy_table_t *table);
+void policy_init_default(policy_table_t *table, uid_t owner_uid);
+int policy_table_add(policy_table_t *table, const policy_entry_t *entry);
+int policy_check(const policy_table_t *table, const char *caller_id,
+                 const char *verb, const char *role_name, const char *purpose,
+                 policy_source_t *out_source);
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* from pq_crypto.h */
+typedef enum { CRYPTO_ALG_SECP256K1=0, CRYPTO_ALG_ED25519, CRYPTO_ALG_X25519, CRYPTO_ALG_ML_DSA_65, CRYPTO_ALG_SLH_DSA_128S, CRYPTO_ALG_ML_KEM_768, CRYPTO_ALG_UNKNOWN } crypto_alg_t;
+typedef struct { size_t priv_key_len; size_t pub_key_len; size_t sig_len; size_t ciphertext_len; size_t shared_secret_len; } crypto_alg_sizes_t;
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+const char *crypto_alg_to_str(crypto_alg_t alg);
+crypto_alg_t crypto_alg_from_str(const char *s);
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len, unsigned char *priv_out, unsigned char *pub_out);
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len, const unsigned char *msg, size_t msg_len, unsigned char *sig_out, size_t *sig_out_len);
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len, const unsigned char *msg, size_t msg_len, const unsigned char *sig, size_t sig_len);
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len, unsigned char *priv_out, unsigned char *pub_out);
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len, const unsigned char *peer_pub, size_t pub_len, unsigned char *shared_out, size_t *shared_out_len);
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path, unsigned char *seed_out, size_t seed_out_len);
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len, unsigned char *priv_out, unsigned char *pub_out);
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len, const unsigned char *msg, size_t msg_len, unsigned char *sig_out, size_t *sig_out_len);
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len, const unsigned char *msg, size_t msg_len, const unsigned char *sig, size_t sig_len);
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len, unsigned char *priv_out, unsigned char *pub_out);
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len, const unsigned char *msg, size_t msg_len, unsigned char *sig_out, size_t *sig_out_len);
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len, const unsigned char *msg, size_t msg_len, const unsigned char *sig, size_t sig_len);
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len, unsigned char *priv_out, unsigned char *pub_out);
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len, unsigned char *ct_out, unsigned char *ss_out);
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len, const unsigned char *ct, size_t ct_len, unsigned char *ss_out);
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+/* from alg_api.h */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len, const unsigned char *msg, size_t msg_len, unsigned char *sig_out, size_t *sig_out_len);
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len, const unsigned char *msg, size_t msg_len, const unsigned char *sig, size_t sig_len);
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len, const unsigned char *msg, size_t msg_len, unsigned char *sig_out, size_t *sig_out_len);
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len, const unsigned char *msg, size_t msg_len, const unsigned char *sig, size_t sig_len);
+#define ALG_KEY_CACHE_MAX 32
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+typedef struct { alg_key_entry_t entries[ALG_KEY_CACHE_MAX]; int count; } algorithm_key_cache_t;
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+/* from crypto.h */
+typedef struct {
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char npub[128];
+    crypto_alg_t alg;
+    int valid;
+} derived_key_t;
+typedef struct { derived_key_t keys[ROLE_TABLE_MAX_ENTRIES]; int count; } key_store_t;
+int crypto_derive_all(key_store_t *store, role_table_t *table, const mnemonic_state_t *mnemonic);
+const unsigned char *crypto_get_private_key(const key_store_t *store, int role_index);
+const char *crypto_get_pubkey_hex(const key_store_t *store, int role_index);
+char *crypto_sign_event(const key_store_t *store, int role_index, const char *event_json);
+void crypto_wipe(key_store_t *store);
+
+/* from dispatcher.h */
+typedef struct {
+    role_table_t *role_table;
+    mnemonic_state_t *mnemonic;
+    key_store_t *key_store;
+    algorithm_key_cache_t *alg_key_cache;
+} dispatcher_ctx_t;
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
+char *dispatcher_handle_request(dispatcher_ctx_t *ctx, const char *json_request);
+
+/* from main.h */
+#define NSIGNER_VERSION "v0.0.2"
+/* NSIGNER_HEADERLESS_DECLS_END */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <nostr_core/utils.h>
+#include <nostr_core/nostr_common.h>
+
+static int g_passes = 0;
+static int g_total = 0;
+
+static void check(const char *name, int condition) {
+    g_total++;
+    if (condition) {
+        printf("PASS: %s\n", name);
+        g_passes++;
+    } else {
+        printf("FAIL: %s\n", name);
+    }
+}
+
+static int resp_has(const char *resp, const char *needle) {
+    return (resp != NULL && needle != NULL && strstr(resp, needle) != NULL);
+}
+
+/* Extract a string field from a JSON result object embedded in a response.
+ * The response format is {"id":"...","result":"{...}"} where the result
+ * value is a JSON string. This extracts the result string, parses it,
+ * and returns the value of the given field. Caller must free. */
+static char *extract_result_field(const char *response, const char *field) {
+    cJSON *root, *result_item, *result_obj, *field_item;
+    char *out = NULL;
+
+    if (response == NULL || field == NULL) return NULL;
+
+    root = cJSON_Parse(response);
+    if (root == NULL) return NULL;
+
+    result_item = cJSON_GetObjectItemCaseSensitive(root, "result");
+    if (!cJSON_IsString(result_item) || result_item->valuestring == NULL) {
+        cJSON_Delete(root);
+        return NULL;
+    }
+
+    result_obj = cJSON_Parse(result_item->valuestring);
+    if (result_obj == NULL) {
+        cJSON_Delete(root);
+        return NULL;
+    }
+
+    field_item = cJSON_GetObjectItemCaseSensitive(result_obj, field);
+    if (cJSON_IsString(field_item) && field_item->valuestring != NULL) {
+        out = strdup(field_item->valuestring);
+    }
+
+    cJSON_Delete(result_obj);
+    cJSON_Delete(root);
+    return out;
+}
+
+static int extract_result_bool(const char *response, const char *field) {
+    cJSON *root, *result_item, *result_obj, *field_item;
+    int val = -1;
+
+    if (response == NULL || field == NULL) return -1;
+
+    root = cJSON_Parse(response);
+    if (root == NULL) return -1;
+
+    result_item = cJSON_GetObjectItemCaseSensitive(root, "result");
+    if (!cJSON_IsString(result_item) || result_item->valuestring == NULL) {
+        cJSON_Delete(root);
+        return -1;
+    }
+
+    result_obj = cJSON_Parse(result_item->valuestring);
+    if (result_obj == NULL) {
+        cJSON_Delete(root);
+        return -1;
+    }
+
+    field_item = cJSON_GetObjectItemCaseSensitive(result_obj, field);
+    if (cJSON_IsBool(field_item)) {
+        val = cJSON_IsTrue(field_item) ? 1 : 0;
+    }
+
+    cJSON_Delete(result_obj);
+    cJSON_Delete(root);
+    return val;
+}
+
+/* File-level statics to avoid stack overflow (key_store_t is ~2.1MB) */
+static key_store_t g_key_store;
+static algorithm_key_cache_t g_alg_key_cache;
+static mnemonic_state_t g_mnemonic;
+static role_table_t g_role_table;
+static dispatcher_ctx_t g_dispatcher;
+
+int main(void) {
+    const char *valid_12 = "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about";
+    char *resp;
+    char *sig_hex;
+    char *pub_hex;
+    char *ct_hex;
+    char *ss_hex1;
+    char *ss_hex2;
+    char *shared_hex;
+    char request[32768];
+    int rc;
+
+    /* ---- Setup ---- */
+    role_table_init(&g_role_table);
+    {
+        role_entry_t main_role;
+        memset(&main_role, 0, sizeof(main_role));
+        strncpy(main_role.name, "main", sizeof(main_role.name) - 1);
+        strncpy(main_role.purpose_str, "nostr", sizeof(main_role.purpose_str) - 1);
+        strncpy(main_role.curve_str, "secp256k1", sizeof(main_role.curve_str) - 1);
+        main_role.purpose = role_purpose_from_str("nostr");
+        main_role.curve = role_curve_from_str("secp256k1");
+        main_role.selector_type = SELECTOR_NOSTR_INDEX;
+        main_role.nostr_index = 0;
+        role_table_add(&g_role_table, &main_role);
+    }
+
+    mnemonic_init(&g_mnemonic);
+    rc = mnemonic_load(&g_mnemonic, valid_12);
+    check("mnemonic_load succeeds", rc == 0);
+
+    memset(&g_key_store, 0, sizeof(g_key_store));
+    alg_key_cache_init(&g_alg_key_cache);
+
+    rc = nostr_init();
+    check("nostr_init succeeds", rc == 0);
+
+    crypto_derive_all(&g_key_store, &g_role_table, &g_mnemonic);
+
+    dispatcher_init(&g_dispatcher, &g_role_table, &g_mnemonic, &g_key_store, &g_alg_key_cache);
+
+    /* ---- Enforcement tests ---- */
+    check("enforce sign + ed25519 -> OK",
+          enforce_verb_algorithm(VERB_SIGN, CRYPTO_ALG_ED25519) == ENFORCE_OK);
+    check("enforce sign + secp256k1 -> OK",
+          enforce_verb_algorithm(VERB_SIGN, CRYPTO_ALG_SECP256K1) == ENFORCE_OK);
+    check("enforce sign + ml-dsa-65 -> OK",
+          enforce_verb_algorithm(VERB_SIGN, CRYPTO_ALG_ML_DSA_65) == ENFORCE_OK);
+    check("enforce sign + slh-dsa-128s -> OK",
+          enforce_verb_algorithm(VERB_SIGN, CRYPTO_ALG_SLH_DSA_128S) == ENFORCE_OK);
+    check("enforce sign + x25519 -> ALGORITHM err",
+          enforce_verb_algorithm(VERB_SIGN, CRYPTO_ALG_X25519) == ENFORCE_ERR_ALGORITHM);
+    check("enforce sign + ml-kem-768 -> ALGORITHM err",
+          enforce_verb_algorithm(VERB_SIGN, CRYPTO_ALG_ML_KEM_768) == ENFORCE_ERR_ALGORITHM);
+    check("enforce encapsulate + ml-kem-768 -> OK",
+          enforce_verb_algorithm(VERB_ENCAPSULATE, CRYPTO_ALG_ML_KEM_768) == ENFORCE_OK);
+    check("enforce encapsulate + ed25519 -> ALGORITHM err",
+          enforce_verb_algorithm(VERB_ENCAPSULATE, CRYPTO_ALG_ED25519) == ENFORCE_ERR_ALGORITHM);
+    check("enforce decapsulate + ml-kem-768 -> OK",
+          enforce_verb_algorithm(VERB_DECAPSULATE, CRYPTO_ALG_ML_KEM_768) == ENFORCE_OK);
+    check("enforce derive_shared_secret + x25519 -> OK",
+          enforce_verb_algorithm(VERB_DERIVE_SHARED, CRYPTO_ALG_X25519) == ENFORCE_OK);
+    check("enforce derive_shared_secret + ed25519 -> ALGORITHM err",
+          enforce_verb_algorithm(VERB_DERIVE_SHARED, CRYPTO_ALG_ED25519) == ENFORCE_ERR_ALGORITHM);
+    check("enforce get_public_key + any alg -> OK",
+          enforce_verb_algorithm(VERB_GET_PUBLIC_KEY, CRYPTO_ALG_ED25519) == ENFORCE_OK);
+    check("enforce sign_event + secp256k1 -> OK",
+          enforce_verb_algorithm(VERB_SIGN_EVENT, CRYPTO_ALG_SECP256K1) == ENFORCE_OK);
+    check("enforce sign_event + ed25519 -> ALGORITHM err",
+          enforce_verb_algorithm(VERB_SIGN_EVENT, CRYPTO_ALG_ED25519) == ENFORCE_ERR_ALGORITHM);
+
+    /* ---- get_public_key with algorithm parameter ---- */
+    resp = dispatcher_handle_request(&g_dispatcher,
+        "{\"id\":\"gpk1\",\"method\":\"get_public_key\",\"params\":[{\"algorithm\":\"ed25519\",\"index\":0}]}");
+    check("get_public_key algorithm=ed25519 returns result",
+          resp_has(resp, "\"result\""));
+    check("get_public_key algorithm=ed25519 has algorithm field",
+          resp_has(resp, "ed25519"));
+    check("get_public_key algorithm=ed25519 has public_key field",
+          resp_has(resp, "public_key"));
+    check("get_public_key algorithm=ed25519 has key_id field",
+          resp_has(resp, "key_id"));
+    free(resp);
+
+    resp = dispatcher_handle_request(&g_dispatcher,
+        "{\"id\":\"gpk2\",\"method\":\"get_public_key\",\"params\":[{\"algorithm\":\"ml-dsa-65\",\"index\":0}]}");
+    check("get_public_key algorithm=ml-dsa-65 returns result",
+          resp_has(resp, "\"result\""));
+    check("get_public_key algorithm=ml-dsa-65 has algorithm field",
+          resp_has(resp, "ml-dsa-65"));
+    free(resp);
+
+    /* ---- sign + verify roundtrip: ed25519 ---- */
+    resp = dispatcher_handle_request(&g_dispatcher,
+        "{\"id\":\"s1\",\"method\":\"sign\",\"params\":[\"68656c6c6f\",{\"algorithm\":\"ed25519\",\"index\":0}]}");
+    check("sign ed25519 returns result",
+          resp_has(resp, "\"result\""));
+    check("sign ed25519 has signature field",
+          resp_has(resp, "signature"));
+    check("sign ed25519 has algorithm ed25519",
+          resp_has(resp, "ed25519"));
+    check("sign ed25519 has key_id",
+          resp_has(resp, "key_id"));
+    sig_hex = extract_result_field(resp, "signature");
+    free(resp);
+    check("sign ed25519 extracted signature", sig_hex != NULL && strlen(sig_hex) > 0);
+
+    if (sig_hex) {
+        snprintf(request, sizeof(request),
+            "{\"id\":\"v1\",\"method\":\"verify\",\"params\":[\"68656c6c6f\",\"%s\",{\"algorithm\":\"ed25519\",\"index\":0}]}",
+            sig_hex);
+        resp = dispatcher_handle_request(&g_dispatcher, request);
+        check("verify ed25519 returns result", resp_has(resp, "\"result\""));
+        check("verify ed25519 valid:true", extract_result_bool(resp, "valid") == 1);
+        free(resp);
+
+        /* verify with wrong message */
+        snprintf(request, sizeof(request),
+            "{\"id\":\"v2\",\"method\":\"verify\",\"params\":[\"776f726c64\",\"%s\",{\"algorithm\":\"ed25519\",\"index\":0}]}",
+            sig_hex);
+        resp = dispatcher_handle_request(&g_dispatcher, request);
+        check("verify ed25519 wrong msg valid:false", extract_result_bool(resp, "valid") == 0);
+        free(resp);
+
+        free(sig_hex);
+    }
+
+    /* ---- sign + verify roundtrip: ml-dsa-65 ---- */
+    resp = dispatcher_handle_request(&g_dispatcher,
+        "{\"id\":\"s2\",\"method\":\"sign\",\"params\":[\"68656c6c6f\",{\"algorithm\":\"ml-dsa-65\",\"index\":0}]}");
+    check("sign ml-dsa-65 returns result", resp_has(resp, "\"result\""));
+    check("sign ml-dsa-65 has signature", resp_has(resp, "signature"));
+    sig_hex = extract_result_field(resp, "signature");
+    free(resp);
+    check("sign ml-dsa-65 extracted signature", sig_hex != NULL && strlen(sig_hex) > 0);
+
+    if (sig_hex) {
+        snprintf(request, sizeof(request),
+            "{\"id\":\"v3\",\"method\":\"verify\",\"params\":[\"68656c6c6f\",\"%s\",{\"algorithm\":\"ml-dsa-65\",\"index\":0}]}",
+            sig_hex);
+        resp = dispatcher_handle_request(&g_dispatcher, request);
+        check("verify ml-dsa-65 valid:true", extract_result_bool(resp, "valid") == 1);
+        free(resp);
+        free(sig_hex);
+    }
+
+    /* ---- sign + verify roundtrip: slh-dsa-128s ---- */
+    resp = dispatcher_handle_request(&g_dispatcher,
+        "{\"id\":\"s3\",\"method\":\"sign\",\"params\":[\"68656c6c6f\",{\"algorithm\":\"slh-dsa-128s\",\"index\":0}]}");
+    check("sign slh-dsa-128s returns result", resp_has(resp, "\"result\""));
+    sig_hex = extract_result_field(resp, "signature");
+    free(resp);
+    check("sign slh-dsa-128s extracted signature", sig_hex != NULL && strlen(sig_hex) > 0);
+
+    if (sig_hex) {
+        snprintf(request, sizeof(request),
+            "{\"id\":\"v4\",\"method\":\"verify\",\"params\":[\"68656c6c6f\",\"%s\",{\"algorithm\":\"slh-dsa-128s\",\"index\":0}]}",
+            sig_hex);
+        resp = dispatcher_handle_request(&g_dispatcher, request);
+        check("verify slh-dsa-128s valid:true", extract_result_bool(resp, "valid") == 1);
+        free(resp);
+        free(sig_hex);
+    }
+
+    /* ---- sign + verify roundtrip: secp256k1 schnorr ---- */
+    resp = dispatcher_handle_request(&g_dispatcher,
+        "{\"id\":\"s4\",\"method\":\"sign\",\"params\":[\"68656c6c6f\",{\"algorithm\":\"secp256k1\",\"index\":0,\"scheme\":\"schnorr\"}]}");
+    check("sign secp256k1 schnorr returns result", resp_has(resp, "\"result\""));
+    sig_hex = extract_result_field(resp, "signature");
+    free(resp);
+    check("sign secp256k1 schnorr extracted signature", sig_hex != NULL && strlen(sig_hex) == 128);
+
+    if (sig_hex) {
+        snprintf(request, sizeof(request),
+            "{\"id\":\"v5\",\"method\":\"verify\",\"params\":[\"68656c6c6f\",\"%s\",{\"algorithm\":\"secp256k1\",\"index\":0,\"scheme\":\"schnorr\"}]}",
+            sig_hex);
+        resp = dispatcher_handle_request(&g_dispatcher, request);
+        check("verify secp256k1 schnorr valid:true", extract_result_bool(resp, "valid") == 1);
+        free(resp);
+        free(sig_hex);
+    }
+
+    /* ---- sign + verify roundtrip: secp256k1 ecdsa ---- */
+    resp = dispatcher_handle_request(&g_dispatcher,
+        "{\"id\":\"s5\",\"method\":\"sign\",\"params\":[\"68656c6c6f\",{\"algorithm\":\"secp256k1\",\"index\":0,\"scheme\":\"ecdsa\"}]}");
+    check("sign secp256k1 ecdsa returns result", resp_has(resp, "\"result\""));
+    sig_hex = extract_result_field(resp, "signature");
+    free(resp);
+    check("sign secp256k1 ecdsa extracted signature", sig_hex != NULL && strlen(sig_hex) == 128);
+
+    if (sig_hex) {
+        snprintf(request, sizeof(request),
+            "{\"id\":\"v6\",\"method\":\"verify\",\"params\":[\"68656c6c6f\",\"%s\",{\"algorithm\":\"secp256k1\",\"index\":0,\"scheme\":\"ecdsa\"}]}",
+            sig_hex);
+        resp = dispatcher_handle_request(&g_dispatcher, request);
+        check("verify secp256k1 ecdsa valid:true", extract_result_bool(resp, "valid") == 1);
+        free(resp);
+        free(sig_hex);
+    }
+
+    /* ---- encapsulate + decapsulate: ml-kem-768 ---- */
+    /* First get our ML-KEM public key */
+    resp = dispatcher_handle_request(&g_dispatcher,
+        "{\"id\":\"gpk3\",\"method\":\"get_public_key\",\"params\":[{\"algorithm\":\"ml-kem-768\",\"index\":0}]}");
+    pub_hex = extract_result_field(resp, "public_key");
+    check("get_public_key ml-kem-768 returns public_key", pub_hex != NULL && strlen(pub_hex) > 0);
+    free(resp);
+
+    if (pub_hex) {
+        /* Encapsulate with our own public key (for testing) */
+        snprintf(request, sizeof(request),
+            "{\"id\":\"e1\",\"method\":\"encapsulate\",\"params\":[\"%s\",{\"algorithm\":\"ml-kem-768\"}]}",
+            pub_hex);
+        resp = dispatcher_handle_request(&g_dispatcher, request);
+        check("encapsulate ml-kem-768 returns result", resp_has(resp, "\"result\""));
+        check("encapsulate ml-kem-768 has ciphertext", resp_has(resp, "ciphertext"));
+        check("encapsulate ml-kem-768 has shared_secret", resp_has(resp, "shared_secret"));
+        ct_hex = extract_result_field(resp, "ciphertext");
+        ss_hex1 = extract_result_field(resp, "shared_secret");
+        free(resp);
+        check("encapsulate extracted ciphertext", ct_hex != NULL && strlen(ct_hex) > 0);
+        check("encapsulate extracted shared_secret", ss_hex1 != NULL && strlen(ss_hex1) > 0);
+
+        if (ct_hex) {
+            /* Decapsulate with our private key */
+            snprintf(request, sizeof(request),
+                "{\"id\":\"d1\",\"method\":\"decapsulate\",\"params\":[\"%s\",{\"algorithm\":\"ml-kem-768\",\"index\":0}]}",
+                ct_hex);
+            resp = dispatcher_handle_request(&g_dispatcher, request);
+            check("decapsulate ml-kem-768 returns result", resp_has(resp, "\"result\""));
+            check("decapsulate ml-kem-768 has shared_secret", resp_has(resp, "shared_secret"));
+            ss_hex2 = extract_result_field(resp, "shared_secret");
+            free(resp);
+            check("decapsulate extracted shared_secret", ss_hex2 != NULL);
+
+            /* Verify the shared secrets match */
+            if (ss_hex1 && ss_hex2) {
+                check("encapsulate/decapsulate shared secrets match",
+                      strcmp(ss_hex1, ss_hex2) == 0);
+            }
+            free(ss_hex2);
+        }
+        free(ct_hex);
+        free(ss_hex1);
+        free(pub_hex);
+    }
+
+    /* ---- derive_shared_secret: x25519 ---- */
+    /* Get our x25519 public key */
+    resp = dispatcher_handle_request(&g_dispatcher,
+        "{\"id\":\"gpk4\",\"method\":\"get_public_key\",\"params\":[{\"algorithm\":\"x25519\",\"index\":0}]}");
+    pub_hex = extract_result_field(resp, "public_key");
+    check("get_public_key x25519 returns public_key", pub_hex != NULL && strlen(pub_hex) > 0);
+    free(resp);
+
+    if (pub_hex) {
+        /* Derive shared secret with our own public key (for testing) */
+        snprintf(request, sizeof(request),
+            "{\"id\":\"dss1\",\"method\":\"derive_shared_secret\",\"params\":[\"%s\",{\"algorithm\":\"x25519\",\"index\":0}]}",
+            pub_hex);
+        resp = dispatcher_handle_request(&g_dispatcher, request);
+        check("derive_shared_secret x25519 returns result", resp_has(resp, "\"result\""));
+        check("derive_shared_secret x25519 has shared_secret", resp_has(resp, "shared_secret"));
+        check("derive_shared_secret x25519 has algorithm x25519", resp_has(resp, "x25519"));
+        shared_hex = extract_result_field(resp, "shared_secret");
+        free(resp);
+        check("derive_shared_secret extracted shared_secret", shared_hex != NULL && strlen(shared_hex) == 64);
+        free(shared_hex);
+        free(pub_hex);
+    }
+
+    /* ---- Enforcement via dispatcher: sign with x25519 fails ---- */
+    resp = dispatcher_handle_request(&g_dispatcher,
+        "{\"id\":\"err1\",\"method\":\"sign\",\"params\":[\"68656c6c6f\",{\"algorithm\":\"x25519\",\"index\":0}]}");
+    check("sign x25519 returns algorithm error",
+          resp_has(resp, "algorithm_not_supported_for_verb") || resp_has(resp, "\"code\":1010"));
+    free(resp);
+
+    /* ---- Enforcement via dispatcher: encapsulate with ed25519 fails ---- */
+    resp = dispatcher_handle_request(&g_dispatcher,
+        "{\"id\":\"err2\",\"method\":\"encapsulate\",\"params\":[\"abcd\",{\"algorithm\":\"ed25519\"}]}");
+    check("encapsulate ed25519 returns algorithm error",
+          resp_has(resp, "algorithm_not_supported_for_verb") || resp_has(resp, "\"code\":1010"));
+    free(resp);
+
+    /* ---- Old verb alias: sign_data with algorithm=ed25519 ---- */
+    resp = dispatcher_handle_request(&g_dispatcher,
+        "{\"id\":\"alias1\",\"method\":\"sign_data\",\"params\":[\"68656c6c6f\",{\"algorithm\":\"ed25519\",\"index\":0}]}");
+    check("sign_data alias with algorithm=ed25519 returns result",
+          resp_has(resp, "\"result\""));
+    check("sign_data alias has signature",
+          resp_has(resp, "signature"));
+    free(resp);
+
+    /* ---- Old verb alias: ssh_sign with algorithm=ed25519 ---- */
+    resp = dispatcher_handle_request(&g_dispatcher,
+        "{\"id\":\"alias2\",\"method\":\"ssh_sign\",\"params\":[\"68656c6c6f\",{\"algorithm\":\"ed25519\",\"index\":0}]}");
+    check("ssh_sign alias with algorithm=ed25519 returns result",
+          resp_has(resp, "\"result\""));
+    free(resp);
+
+    /* ---- Old verb alias: kem_encapsulate with algorithm=ml-kem-768 ---- */
+    resp = dispatcher_handle_request(&g_dispatcher,
+        "{\"id\":\"gpk5\",\"method\":\"get_public_key\",\"params\":[{\"algorithm\":\"ml-kem-768\",\"index\":1}]}");
+    pub_hex = extract_result_field(resp, "public_key");
+    free(resp);
+    if (pub_hex) {
+        snprintf(request, sizeof(request),
+            "{\"id\":\"alias3\",\"method\":\"kem_encapsulate\",\"params\":[\"%s\",{\"algorithm\":\"ml-kem-768\"}]}",
+            pub_hex);
+        resp = dispatcher_handle_request(&g_dispatcher, request);
+        check("kem_encapsulate alias with algorithm=ml-kem-768 returns result",
+              resp_has(resp, "\"result\""));
+        check("kem_encapsulate alias has ciphertext",
+              resp_has(resp, "ciphertext"));
+        free(resp);
+        free(pub_hex);
+    }
+
+    /* ---- Backward compat: sign_event with role still works ---- */
+    resp = dispatcher_handle_request(&g_dispatcher,
+        "{\"id\":\"bc1\",\"method\":\"sign_event\",\"params\":[\"{\\\"kind\\\":1,\\\"content\\\":\\\"hello\\\",\\\"tags\\\":[]}\",{\"role\":\"main\"}]}");
+    check("sign_event with role=main (backward compat) returns signed event",
+          resp_has(resp, "pubkey") && resp_has(resp, "sig"));
+    free(resp);
+
+    /* ---- Backward compat: get_public_key with role still works ---- */
+    resp = dispatcher_handle_request(&g_dispatcher,
+        "{\"id\":\"bc2\",\"method\":\"get_public_key\",\"params\":[{\"role\":\"main\"}]}");
+    check("get_public_key with role=main (backward compat) returns hex",
+          resp_has(resp, "\"result\""));
+    free(resp);
+
+    /* ---- Policy: algorithm-based preapprove ---- */
+    {
+        policy_table_t policy;
+        policy_entry_t entry;
+        policy_source_t src;
+
+        policy_init_default(&policy, 1000);
+
+        /* Add algorithm-based preapprove entry */
+        memset(&entry, 0, sizeof(entry));
+        strncpy(entry.caller, "uid:1000", sizeof(entry.caller) - 1);
+        strncpy(entry.algorithms[0], "ed25519", sizeof(entry.algorithms[0]) - 1);
+        entry.alg_count = 1;
+        entry.index_min = 0;
+        entry.index_max = 4;
+        strncpy(entry.verbs[0], "sign", sizeof(entry.verbs[0]) - 1);
+        strncpy(entry.verbs[1], "verify", sizeof(entry.verbs[1]) - 1);
+        entry.verb_count = 2;
+        entry.prompt = PROMPT_NEVER;
+        entry.source = POLICY_SOURCE_PREAPPROVE;
+        policy_table_add(&policy, &entry);
+
+        /* Check: allowed */
+        rc = policy_check_algorithm(&policy, "uid:1000", "sign", "ed25519", 0, &src);
+        check("policy_check_algorithm: sign ed25519 idx=0 -> ALLOW", rc == POLICY_ALLOW);
+
+        rc = policy_check_algorithm(&policy, "uid:1000", "sign", "ed25519", 3, &src);
+        check("policy_check_algorithm: sign ed25519 idx=3 -> ALLOW", rc == POLICY_ALLOW);
+
+        /* Check: index out of range */
+        rc = policy_check_algorithm(&policy, "uid:1000", "sign", "ed25519", 5, &src);
+        check("policy_check_algorithm: sign ed25519 idx=5 -> NO_MATCH", rc == POLICY_NO_MATCH);
+
+        /* Check: wrong algorithm */
+        rc = policy_check_algorithm(&policy, "uid:1000", "sign", "ml-dsa-65", 0, &src);
+        check("policy_check_algorithm: sign ml-dsa-65 -> NO_MATCH", rc == POLICY_NO_MATCH);
+
+        /* Check: wrong verb */
+        rc = policy_check_algorithm(&policy, "uid:1000", "encapsulate", "ed25519", 0, &src);
+        check("policy_check_algorithm: encapsulate ed25519 -> NO_MATCH", rc == POLICY_NO_MATCH);
+
+        /* Check: wrong caller */
+        rc = policy_check_algorithm(&policy, "uid:2000", "sign", "ed25519", 0, &src);
+        check("policy_check_algorithm: wrong caller -> NO_MATCH", rc == POLICY_NO_MATCH);
+    }
+
+    /* ---- Cleanup ---- */
+    crypto_wipe(&g_key_store);
+    alg_key_cache_wipe(&g_alg_key_cache);
+    nostr_cleanup();
+    mnemonic_unload(&g_mnemonic);
+
+    printf("%d/%d tests passed\n", g_passes, g_total);
+    return (g_passes == g_total) ? 0 : 1;
+}

tests/test_dispatcher.c

@@ -82,6 +82,8 @@ typedef enum {
     PURPOSE_SSH,
     PURPOSE_AGE,
     PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,      /* post-quantum signatures (ML-DSA, SLH-DSA) */
+    PURPOSE_PQ_KEM,      /* post-quantum key encapsulation (ML-KEM) */
     PURPOSE_UNKNOWN
 } role_purpose_t;
 
@@ -90,6 +92,9 @@ typedef enum {
     CURVE_SECP256K1 = 0,
     CURVE_ED25519,
     CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
     CURVE_UNKNOWN
 } role_curve_t;
 
@@ -198,6 +203,24 @@ const char *selector_strerror(int err);
 #define ENFORCE_ERR_PURPOSE      -1 /* purpose mismatch */
 #define ENFORCE_ERR_CURVE        -2 /* curve mismatch */
 #define ENFORCE_ERR_UNKNOWN_VERB -3 /* verb not recognized */
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
 
 /* Known verbs */
 #define VERB_SIGN_EVENT     "sign_event"
@@ -233,6 +256,8 @@ const char *enforce_strerror(int err);
 #define POLICY_MAX_PURPOSES   8
 #define POLICY_VERB_MAX_LEN   32
 #define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
 
 /* Prompt behavior */
 typedef enum {
@@ -257,6 +282,12 @@ typedef struct {
     int role_count;
     char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
     int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
     prompt_mode_t prompt;
     policy_source_t source;
 } policy_entry_t;
@@ -290,6 +321,20 @@ int policy_check(const policy_table_t *table, const char *caller_id,
                  const char *verb, const char *role_name, const char *purpose,
                  policy_source_t *out_source);
 
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
 /* Parse prompt mode from string */
 prompt_mode_t prompt_mode_from_str(const char *s);
 
@@ -297,15 +342,147 @@ prompt_mode_t prompt_mode_from_str(const char *s);
 const char *prompt_mode_to_str(prompt_mode_t m);
 
 
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,   /* existing, Nostr */
+    CRYPTO_ALG_ED25519,         /* new, SSH signatures */
+    CRYPTO_ALG_X25519,          /* new, key agreement */
+    CRYPTO_ALG_ML_DSA_65,       /* new, PQ signatures */
+    CRYPTO_ALG_SLH_DSA_128S,    /* new, PQ signatures */
+    CRYPTO_ALG_ML_KEM_768,      /* new, PQ KEM */
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;           /* 0 for KEM */
+    size_t ciphertext_len;    /* 0 for signatures */
+    size_t shared_secret_len; /* 0 for signatures */
+} crypto_alg_sizes_t;
+
+/* Get size info for an algorithm. Returns NULL for CRYPTO_ALG_UNKNOWN. */
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+
+/* Map role_curve_t + role_purpose_t to crypto_alg_t.
+ * Returns CRYPTO_ALG_UNKNOWN for unsupported combinations. */
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+
+/* Convert crypto_alg_t to string. Returns NULL for unknown. */
+const char *crypto_alg_to_str(crypto_alg_t alg);
+
+/* Parse string to crypto_alg_t. Returns CRYPTO_ALG_UNKNOWN for unrecognized. */
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+
+
 /* from crypto.h */
 
 
 /* Per-role derived key material (stored in secure memory) */
 typedef struct {
-    secure_buf_t private_key;  /* 32 bytes, mlock'd */
-    unsigned char public_key[32];
-    char pubkey_hex[65];       /* 64 hex chars + null */
-    char npub[128];            /* bech32 npub */
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
     int valid;
 } derived_key_t;
 
@@ -339,6 +516,82 @@ char *crypto_sign_event(const key_store_t *store, int role_index, const char *ev
 void crypto_wipe(key_store_t *store);
 
 
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
 /* from dispatcher.h */
 
 
@@ -347,10 +600,11 @@ typedef struct {
     role_table_t *role_table;
     mnemonic_state_t *mnemonic;
     key_store_t *key_store;
+    algorithm_key_cache_t *alg_key_cache;  /* algorithm-based on-demand keys */
 } dispatcher_ctx_t;
 
 /* Initialize dispatcher context */
-void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store);
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
 
 /*
  * Process a JSON-RPC request string and produce a JSON-RPC response string.
@@ -517,6 +771,7 @@ int main(void) {
     mnemonic_state_t mnemonic;
     dispatcher_ctx_t dispatcher;
     key_store_t key_store;
+    static algorithm_key_cache_t alg_key_cache;
     const char *valid_12 = "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about";
     char *resp;
     int derived;
@@ -536,7 +791,8 @@ int main(void) {
     mnemonic_load(&mnemonic, valid_12);
 
     memset(&key_store, 0, sizeof(key_store));
-    dispatcher_init(&dispatcher, &table, &mnemonic, &key_store);
+    alg_key_cache_init(&alg_key_cache);
+    dispatcher_init(&dispatcher, &table, &mnemonic, &key_store, &alg_key_cache);
 
     derived = nostr_init();
     check_condition("nostr_init succeeds", derived == 0);

tests/test_ed25519_x25519.c

@@ -0,0 +1,901 @@
+/* Test for Phase 2 ed25519 + x25519 crypto (pq_crypto.c, key_store.c,
+ * enforcement.c, dispatcher.c).
+ *
+ * Verifies:
+ *   - ed25519 keygen from seed: 32-byte priv/pub
+ *   - ed25519 sign/verify roundtrip + wrong-message fails
+ *   - ed25519 determinism: same seed -> same keypair
+ *   - x25519 keygen from seed: 32-byte priv/pub
+ *   - x25519 ECDH roundtrip: two sides derive matching shared secret
+ *   - x25519 determinism: same seed -> same keypair
+ *   - SLIP-0010 derivation: deterministic seed from mnemonic+path
+ *   - Integration: derive ed25519 key via crypto_derive_one, sign_data via
+ *     dispatcher, verify signature
+ *   - Enforcement: sign_data allowed on ssh+ed25519, rejected on nostr+secp256k1
+ *   - Enforcement: ssh_sign allowed on ssh+ed25519
+ *   - Enforcement: kem_encapsulate/decapsulate rejected on ssh/ed25519
+ */
+/* NSIGNER_HEADERLESS_DECLS_BEGIN */
+#include <stddef.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <cJSON.h>
+
+/* from secure_mem.h */
+
+
+typedef struct {
+    void *data;
+    size_t size;
+    int locked;
+} secure_buf_t;
+
+int secure_buf_alloc(secure_buf_t *buf, size_t size);
+void secure_buf_free(secure_buf_t *buf);
+void secure_memzero(void *ptr, size_t len);
+
+
+/* from mnemonic.h */
+
+
+#define MNEMONIC_MAX_LEN 256
+
+typedef struct {
+    secure_buf_t buf;
+    int loaded;
+    int word_count;
+} mnemonic_state_t;
+
+void mnemonic_init(mnemonic_state_t *state);
+int mnemonic_load(mnemonic_state_t *state, const char *phrase);
+void mnemonic_unload(mnemonic_state_t *state);
+int mnemonic_is_loaded(const mnemonic_state_t *state);
+const char *mnemonic_get_phrase(const mnemonic_state_t *state);
+int mnemonic_generate(int word_count, char *out, size_t out_len);
+
+
+/* from role_table.h */
+
+
+#define ROLE_NAME_MAX 64
+#define ROLE_PATH_MAX 128
+#define ROLE_PURPOSE_MAX 32
+#define ROLE_CURVE_MAX 16
+#define ROLE_PUBKEY_HEX_MAX 66
+#define ROLE_TABLE_MAX_ENTRIES 256
+
+typedef enum {
+    PURPOSE_NOSTR = 0,
+    PURPOSE_BITCOIN,
+    PURPOSE_SSH,
+    PURPOSE_AGE,
+    PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,
+    PURPOSE_PQ_KEM,
+    PURPOSE_UNKNOWN
+} role_purpose_t;
+
+typedef enum {
+    CURVE_SECP256K1 = 0,
+    CURVE_ED25519,
+    CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
+    CURVE_UNKNOWN
+} role_curve_t;
+
+typedef enum {
+    SELECTOR_NOSTR_INDEX,
+    SELECTOR_ROLE_PATH
+} role_selector_type_t;
+
+typedef struct {
+    char name[ROLE_NAME_MAX];
+    char purpose_str[ROLE_PURPOSE_MAX];
+    char curve_str[ROLE_CURVE_MAX];
+    role_purpose_t purpose;
+    role_curve_t curve;
+    role_selector_type_t selector_type;
+    int nostr_index;
+    char role_path[ROLE_PATH_MAX];
+    char pubkey_hex[ROLE_PUBKEY_HEX_MAX];
+    int derived;
+} role_entry_t;
+
+typedef struct {
+    role_entry_t entries[ROLE_TABLE_MAX_ENTRIES];
+    int count;
+} role_table_t;
+
+void role_table_init(role_table_t *table);
+int role_table_add(role_table_t *table, const role_entry_t *entry);
+role_entry_t *role_table_find_by_name(role_table_t *table, const char *name);
+role_entry_t *role_table_find_by_nostr_index(role_table_t *table, int index);
+role_entry_t *role_table_find_by_path(role_table_t *table, const char *path);
+role_entry_t *role_table_get_default(role_table_t *table);
+role_purpose_t role_purpose_from_str(const char *s);
+role_curve_t role_curve_from_str(const char *s);
+const char *role_purpose_to_str(role_purpose_t p);
+const char *role_curve_to_str(role_curve_t c);
+int role_table_register_nostr_index(role_table_t *table, int nostr_index);
+
+
+/* from selector.h */
+
+
+#define SELECTOR_OK                 0
+#define SELECTOR_ERR_AMBIGUOUS     -1
+#define SELECTOR_ERR_NOT_FOUND     -2
+#define SELECTOR_ERR_NO_DEFAULT    -3
+
+typedef struct {
+    int has_role;
+    char role_name[ROLE_NAME_MAX];
+    int has_nostr_index;
+    int nostr_index;
+    int has_role_path;
+    char role_path[ROLE_PATH_MAX];
+} selector_request_t;
+
+void selector_request_init(selector_request_t *req);
+int selector_resolve(const selector_request_t *req, role_table_t *table, role_entry_t **out);
+const char *selector_strerror(int err);
+
+
+/* from enforcement.h */
+
+
+#define ENFORCE_OK                0
+#define ENFORCE_ERR_PURPOSE      -1
+#define ENFORCE_ERR_CURVE        -2
+#define ENFORCE_ERR_UNKNOWN_VERB -3
+
+#define VERB_SIGN_EVENT     "sign_event"
+#define VERB_GET_PUBLIC_KEY "get_public_key"
+#define VERB_NIP44_ENCRYPT  "nip44_encrypt"
+#define VERB_NIP44_DECRYPT  "nip44_decrypt"
+#define VERB_NIP04_ENCRYPT  "nip04_encrypt"
+#define VERB_NIP04_DECRYPT  "nip04_decrypt"
+#define VERB_MINE_EVENT     "mine_event"
+#define VERB_SIGN_DATA      "sign_data"
+#define VERB_VERIFY_SIG     "verify_signature"
+#define VERB_SSH_SIGN       "ssh_sign"
+#define VERB_KEM_ENCAPS     "kem_encapsulate"
+#define VERB_KEM_DECAPS     "kem_decapsulate"
+
+int enforce_verb_role(const char *verb, const role_entry_t *role);
+const char *enforce_strerror(int err);
+
+
+/* from policy.h */
+
+
+#define POLICY_MAX_ENTRIES    32
+#define POLICY_MAX_VERBS      16
+#define POLICY_MAX_ROLES      16
+#define POLICY_MAX_PURPOSES   8
+#define POLICY_VERB_MAX_LEN   32
+#define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
+
+typedef enum {
+    PROMPT_NEVER = 0,
+    PROMPT_FIRST_PER_BOOT,
+    PROMPT_EVERY_REQUEST,
+    PROMPT_DENY
+} prompt_mode_t;
+
+typedef enum {
+    POLICY_SOURCE_DEFAULT = 0,
+    POLICY_SOURCE_PREAPPROVE,
+    POLICY_SOURCE_SESSION_GRANT
+} policy_source_t;
+
+typedef struct {
+    char caller[POLICY_CALLER_MAX_LEN];
+    char verbs[POLICY_MAX_VERBS][POLICY_VERB_MAX_LEN];
+    int verb_count;
+    char roles[POLICY_MAX_ROLES][ROLE_NAME_MAX];
+    int role_count;
+    char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
+    int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
+    prompt_mode_t prompt;
+    policy_source_t source;
+} policy_entry_t;
+
+typedef struct {
+    policy_entry_t entries[POLICY_MAX_ENTRIES];
+    int count;
+} policy_table_t;
+
+#define POLICY_ALLOW     0
+#define POLICY_DENY     -1
+#define POLICY_PROMPT   -2
+#define POLICY_NO_MATCH -3
+
+void policy_table_init(policy_table_t *table);
+void policy_init_default(policy_table_t *table, uid_t owner_uid);
+int policy_table_add(policy_table_t *table, const policy_entry_t *entry);
+int policy_check(const policy_table_t *table, const char *caller_id,
+                 const char *verb, const char *role_name, const char *purpose,
+                 policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+prompt_mode_t prompt_mode_from_str(const char *s);
+const char *prompt_mode_to_str(prompt_mode_t m);
+
+
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,
+    CRYPTO_ALG_ED25519,
+    CRYPTO_ALG_X25519,
+    CRYPTO_ALG_ML_DSA_65,
+    CRYPTO_ALG_SLH_DSA_128S,
+    CRYPTO_ALG_ML_KEM_768,
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;
+    size_t ciphertext_len;
+    size_t shared_secret_len;
+} crypto_alg_sizes_t;
+
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+const char *crypto_alg_to_str(crypto_alg_t alg);
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+
+/* from crypto.h */
+
+
+/* Per-role derived key material (stored in secure memory) */
+typedef struct {
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
+    int valid;
+} derived_key_t;
+
+typedef struct {
+    derived_key_t keys[ROLE_TABLE_MAX_ENTRIES];
+    int count;
+} key_store_t;
+
+int crypto_derive_all(key_store_t *store, role_table_t *table, const mnemonic_state_t *mnemonic);
+int crypto_derive_one(key_store_t *store, role_table_t *table, const mnemonic_state_t *mnemonic, int role_index);
+const unsigned char *crypto_get_private_key(const key_store_t *store, int role_index);
+const char *crypto_get_pubkey_hex(const key_store_t *store, int role_index);
+char *crypto_sign_event(const key_store_t *store, int role_index, const char *event_json);
+void crypto_wipe(key_store_t *store);
+
+
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
+/* from dispatcher.h */
+
+
+typedef struct {
+    role_table_t *role_table;
+    mnemonic_state_t *mnemonic;
+    key_store_t *key_store;
+} dispatcher_ctx_t;
+
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
+char *dispatcher_handle_request(dispatcher_ctx_t *ctx, const char *json_request);
+
+
+/* NSIGNER_HEADERLESS_DECLS_END */
+
+static algorithm_key_cache_t g_alg_key_cache;
+
+#include <nostr_core/nostr_common.h>
+#include <nostr_core/utils.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static int g_passes = 0;
+static int g_total = 0;
+
+static void check_condition(const char *name, int condition) {
+    g_total++;
+    if (condition) {
+        printf("PASS: %s\n", name);
+        g_passes++;
+    } else {
+        printf("FAIL: %s\n", name);
+    }
+}
+
+static int response_has(const char *response, const char *needle) {
+    return (response != NULL && needle != NULL && strstr(response, needle) != NULL);
+}
+
+static role_entry_t make_ssh_ed25519_entry(const char *name, int idx) {
+    role_entry_t e;
+    memset(&e, 0, sizeof(e));
+    strncpy(e.name, name, sizeof(e.name) - 1);
+    strncpy(e.purpose_str, "ssh", sizeof(e.purpose_str) - 1);
+    strncpy(e.curve_str, "ed25519", sizeof(e.curve_str) - 1);
+    e.purpose = role_purpose_from_str(e.purpose_str);
+    e.curve = role_curve_from_str(e.curve_str);
+    e.selector_type = SELECTOR_NOSTR_INDEX;
+    e.nostr_index = idx;
+    e.derived = 0;
+    return e;
+}
+
+static role_entry_t make_nostr_secp_entry(const char *name, int idx) {
+    role_entry_t e;
+    memset(&e, 0, sizeof(e));
+    strncpy(e.name, name, sizeof(e.name) - 1);
+    strncpy(e.purpose_str, "nostr", sizeof(e.purpose_str) - 1);
+    strncpy(e.curve_str, "secp256k1", sizeof(e.curve_str) - 1);
+    e.purpose = role_purpose_from_str(e.purpose_str);
+    e.curve = role_curve_from_str(e.curve_str);
+    e.selector_type = SELECTOR_NOSTR_INDEX;
+    e.nostr_index = idx;
+    e.derived = 0;
+    return e;
+}
+
+static role_entry_t make_pq_kem_entry(const char *name, int idx) {
+    role_entry_t e;
+    memset(&e, 0, sizeof(e));
+    strncpy(e.name, name, sizeof(e.name) - 1);
+    strncpy(e.purpose_str, "pq-kem", sizeof(e.purpose_str) - 1);
+    strncpy(e.curve_str, "ml-kem-768", sizeof(e.curve_str) - 1);
+    e.purpose = role_purpose_from_str(e.purpose_str);
+    e.curve = role_curve_from_str(e.curve_str);
+    e.selector_type = SELECTOR_NOSTR_INDEX;
+    e.nostr_index = idx;
+    e.derived = 0;
+    return e;
+}
+
+int main(void) {
+    /* Test mnemonic (BIP-39 standard test vector). */
+    const char *mnemonic = "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about";
+    unsigned char seed[32];
+    unsigned char priv1[32], pub1[32];
+    unsigned char priv2[32], pub2[32];
+    unsigned char sig[64];
+    size_t sig_len;
+    size_t shared_len;
+    int rc;
+
+    /* ---- ed25519 keygen from seed ---- */
+    memset(seed, 0x42, 32);
+    rc = crypto_ed25519_keygen_from_seed(seed, 32, priv1, pub1);
+    check_condition("ed25519 keygen from seed succeeds", rc == 0);
+
+    /* Determinism: same seed -> same keypair */
+    rc = crypto_ed25519_keygen_from_seed(seed, 32, priv2, pub2);
+    check_condition("ed25519 keygen determinism (same seed -> same key)", rc == 0 &&
+                    memcmp(priv1, priv2, 32) == 0 && memcmp(pub1, pub2, 32) == 0);
+
+    /* Different seed -> different keypair */
+    memset(seed, 0x99, 32);
+    rc = crypto_ed25519_keygen_from_seed(seed, 32, priv2, pub2);
+    check_condition("ed25519 keygen different seed -> different key", rc == 0 &&
+                    memcmp(priv1, priv2, 32) != 0);
+
+    /* ---- ed25519 sign/verify roundtrip ---- */
+    memset(seed, 0x42, 32);
+    crypto_ed25519_keygen_from_seed(seed, 32, priv1, pub1);
+    {
+        const char *msg = "hello world";
+        sig_len = sizeof(sig);
+        rc = crypto_ed25519_sign(priv1, 32, (const unsigned char *)msg, strlen(msg), sig, &sig_len);
+        check_condition("ed25519 sign succeeds", rc == 0 && sig_len == 64);
+
+        rc = crypto_ed25519_verify(pub1, 32, (const unsigned char *)msg, strlen(msg), sig, sig_len);
+        check_condition("ed25519 verify valid signature", rc == 0);
+
+        /* Wrong message should fail */
+        const char *wrong_msg = "hello worle";
+        rc = crypto_ed25519_verify(pub1, 32, (const unsigned char *)wrong_msg, strlen(wrong_msg), sig, sig_len);
+        check_condition("ed25519 verify wrong message -> invalid", rc == 1);
+
+        /* Wrong key should fail */
+        memset(seed, 0xAB, 32);
+        crypto_ed25519_keygen_from_seed(seed, 32, priv2, pub2);
+        rc = crypto_ed25519_verify(pub2, 32, (const unsigned char *)msg, strlen(msg), sig, sig_len);
+        check_condition("ed25519 verify wrong key -> invalid", rc == 1);
+    }
+
+    /* ---- x25519 keygen from seed ---- */
+    memset(seed, 0x33, 32);
+    rc = crypto_x25519_keygen_from_seed(seed, 32, priv1, pub1);
+    check_condition("x25519 keygen from seed succeeds", rc == 0);
+
+    memset(seed, 0x33, 32);
+    rc = crypto_x25519_keygen_from_seed(seed, 32, priv2, pub2);
+    check_condition("x25519 keygen determinism (same seed -> same key)", rc == 0 &&
+                    memcmp(priv1, priv2, 32) == 0 && memcmp(pub1, pub2, 32) == 0);
+
+    /* ---- x25519 ECDH roundtrip ---- */
+    {
+        unsigned char alice_priv[32], alice_pub[32];
+        unsigned char bob_priv[32], bob_pub[32];
+        unsigned char alice_shared[32], bob_shared[32];
+
+        memset(seed, 0xAA, 32);
+        crypto_x25519_keygen_from_seed(seed, 32, alice_priv, alice_pub);
+        memset(seed, 0xBB, 32);
+        crypto_x25519_keygen_from_seed(seed, 32, bob_priv, bob_pub);
+
+        shared_len = 32;
+        rc = crypto_x25519_ecdh(alice_priv, 32, bob_pub, 32, alice_shared, &shared_len);
+        check_condition("x25519 ECDH alice side succeeds", rc == 0 && shared_len == 32);
+
+        shared_len = 32;
+        rc = crypto_x25519_ecdh(bob_priv, 32, alice_pub, 32, bob_shared, &shared_len);
+        check_condition("x25519 ECDH bob side succeeds", rc == 0 && shared_len == 32);
+
+        check_condition("x25519 ECDH shared secrets match",
+                        memcmp(alice_shared, bob_shared, 32) == 0);
+    }
+
+    /* ---- SLIP-0010 derivation from mnemonic ---- */
+    {
+        unsigned char seed_a[32], seed_b[32];
+        rc = crypto_derive_seed_from_mnemonic(mnemonic, "m/44'/102001'/0'/0'/0'", seed_a, 32);
+        check_condition("SLIP-0010 derive seed succeeds", rc == 0);
+
+        rc = crypto_derive_seed_from_mnemonic(mnemonic, "m/44'/102001'/0'/0'/0'", seed_b, 32);
+        check_condition("SLIP-0010 derive seed determinism", rc == 0 &&
+                        memcmp(seed_a, seed_b, 32) == 0);
+
+        /* Different path -> different seed */
+        rc = crypto_derive_seed_from_mnemonic(mnemonic, "m/44'/102001'/1'/0'/0'", seed_b, 32);
+        check_condition("SLIP-0010 different path -> different seed", rc == 0 &&
+                        memcmp(seed_a, seed_b, 32) != 0);
+
+        /* Non-hardened path should fail (SLIP-0010 requirement) */
+        rc = crypto_derive_seed_from_mnemonic(mnemonic, "m/44'/102001'/0'/0/0", seed_b, 32);
+        check_condition("SLIP-0010 non-hardened path rejected", rc == -1);
+    }
+
+    /* ---- Integration: derive ed25519 key via crypto_derive_one ---- */
+    {
+        role_table_t table;
+        role_entry_t ssh_role;
+        mnemonic_state_t mnemonic_state;
+        key_store_t key_store;
+            int derived;
+
+        role_table_init(&table);
+        ssh_role = make_ssh_ed25519_entry("ssh_main", 0);
+        role_table_add(&table, &ssh_role);
+
+        mnemonic_init(&mnemonic_state);
+        mnemonic_load(&mnemonic_state, mnemonic);
+
+        memset(&key_store, 0, sizeof(key_store));
+        alg_key_cache_init(&g_alg_key_cache);
+    alg_key_cache_init(&g_alg_key_cache);
+        derived = crypto_derive_all(&key_store, &table, &mnemonic_state);
+        check_condition("crypto_derive_all derives ed25519 key", derived == 1);
+
+        {
+            const char *pub_hex = crypto_get_pubkey_hex(&key_store, 0);
+            check_condition("ed25519 derived pubkey hex is 64 chars",
+                            pub_hex != NULL && strlen(pub_hex) == 64);
+        }
+
+        {
+            const unsigned char *priv = crypto_get_private_key(&key_store, 0);
+            check_condition("ed25519 derived private key not NULL", priv != NULL);
+        }
+
+        crypto_wipe(&key_store);
+        mnemonic_unload(&mnemonic_state);
+    }
+
+    /* ---- Integration: sign_data via dispatcher ---- */
+    {
+        role_table_t table;
+        role_entry_t ssh_role;
+        mnemonic_state_t mnemonic_state;
+        key_store_t key_store;
+        dispatcher_ctx_t dispatcher;
+        char *resp;
+        const char *msg_hex = "68656c6c6f20776f726c64"; /* "hello world" in hex */
+        char request[512];
+
+        role_table_init(&table);
+        ssh_role = make_ssh_ed25519_entry("ssh_main", 0);
+        role_table_add(&table, &ssh_role);
+
+        mnemonic_init(&mnemonic_state);
+        mnemonic_load(&mnemonic_state, mnemonic);
+
+        memset(&key_store, 0, sizeof(key_store));
+        alg_key_cache_init(&g_alg_key_cache);
+    alg_key_cache_init(&g_alg_key_cache);
+        crypto_derive_all(&key_store, &table, &mnemonic_state);
+
+        dispatcher_init(&dispatcher, &table, &mnemonic_state, &key_store, &g_alg_key_cache);
+
+        /* sign_data request */
+        snprintf(request, sizeof(request),
+                 "{\"id\":\"test1\",\"method\":\"sign_data\",\"params\":[\"%s\",{\"role\":\"ssh_main\"}]}",
+                 msg_hex);
+        resp = dispatcher_handle_request(&dispatcher, request);
+        check_condition("sign_data via dispatcher returns result",
+                        resp != NULL && response_has(resp, "\"result\""));
+        check_condition("sign_data result contains signature",
+                        resp != NULL && response_has(resp, "signature"));
+        check_condition("sign_data result contains algorithm ed25519",
+                        resp != NULL && response_has(resp, "ed25519"));
+        free(resp);
+
+        /* ssh_sign request */
+        snprintf(request, sizeof(request),
+                 "{\"id\":\"test2\",\"method\":\"ssh_sign\",\"params\":[\"%s\",{\"role\":\"ssh_main\"}]}",
+                 msg_hex);
+        resp = dispatcher_handle_request(&dispatcher, request);
+        check_condition("ssh_sign via dispatcher returns result",
+                        resp != NULL && response_has(resp, "\"result\""));
+        check_condition("ssh_sign result contains signature",
+                        resp != NULL && response_has(resp, "signature"));
+        free(resp);
+
+        crypto_wipe(&key_store);
+        mnemonic_unload(&mnemonic_state);
+    }
+
+    /* ---- Enforcement: sign_data on ssh+ed25519 ---- */
+    {
+        role_entry_t ssh_ed = make_ssh_ed25519_entry("ssh", 0);
+        role_entry_t nostr_secp = make_nostr_secp_entry("nostr", 0);
+        role_entry_t pq_kem = make_pq_kem_entry("kem", 0);
+
+        check_condition("enforce sign_data + ssh/ed25519 -> OK",
+                        enforce_verb_role(VERB_SIGN_DATA, &ssh_ed) == ENFORCE_OK);
+
+        check_condition("enforce sign_data + nostr/secp256k1 -> PURPOSE err",
+                        enforce_verb_role(VERB_SIGN_DATA, &nostr_secp) == ENFORCE_ERR_PURPOSE);
+
+        check_condition("enforce ssh_sign + ssh/ed25519 -> OK",
+                        enforce_verb_role(VERB_SSH_SIGN, &ssh_ed) == ENFORCE_OK);
+
+        check_condition("enforce ssh_sign + nostr/secp256k1 -> PURPOSE err",
+                        enforce_verb_role(VERB_SSH_SIGN, &nostr_secp) == ENFORCE_ERR_PURPOSE);
+
+        check_condition("enforce sign_event + ssh/ed25519 -> PURPOSE err",
+                        enforce_verb_role(VERB_SIGN_EVENT, &ssh_ed) == ENFORCE_ERR_PURPOSE);
+
+        check_condition("enforce kem_encapsulate + pq-kem/ml-kem-768 -> OK",
+                        enforce_verb_role(VERB_KEM_ENCAPS, &pq_kem) == ENFORCE_OK);
+
+        check_condition("enforce kem_decapsulate + pq-kem/ml-kem-768 -> OK",
+                        enforce_verb_role(VERB_KEM_DECAPS, &pq_kem) == ENFORCE_OK);
+
+        check_condition("enforce kem_encapsulate + ssh/ed25519 -> PURPOSE err",
+                        enforce_verb_role(VERB_KEM_ENCAPS, &ssh_ed) == ENFORCE_ERR_PURPOSE);
+    }
+
+    /* ---- Dispatcher: kem_encapsulate with invalid pubkey length ---- */
+    {
+        role_table_t table;
+        role_entry_t kem_role;
+        mnemonic_state_t mnemonic_state;
+        key_store_t key_store;
+        dispatcher_ctx_t dispatcher;
+        char *resp;
+        const char *request = "{\"id\":\"k1\",\"method\":\"kem_encapsulate\",\"params\":[\"00\",{\"role\":\"kem_main\"}]}";
+
+        role_table_init(&table);
+        kem_role = make_pq_kem_entry("kem_main", 0);
+        role_table_add(&table, &kem_role);
+
+        mnemonic_init(&mnemonic_state);
+        mnemonic_load(&mnemonic_state, mnemonic);
+
+        memset(&key_store, 0, sizeof(key_store));
+        alg_key_cache_init(&g_alg_key_cache);
+    alg_key_cache_init(&g_alg_key_cache);
+        dispatcher_init(&dispatcher, &table, &mnemonic_state, &key_store, &g_alg_key_cache);
+
+        /* kem_encapsulate is now implemented (Phase 5). With a too-short
+         * pubkey hex ("00" = 1 byte, but ML-KEM-768 needs 1184 bytes),
+         * the dispatcher should return an invalid_pubkey_length error. */
+        resp = dispatcher_handle_request(&dispatcher, request);
+        check_condition("kem_encapsulate with short pubkey returns error",
+                        resp != NULL && response_has(resp, "\"error\""));
+        free(resp);
+
+        crypto_wipe(&key_store);
+        mnemonic_unload(&mnemonic_state);
+    }
+
+    /* ---- Dispatcher: verify_signature roundtrip ---- */
+    {
+        role_table_t table;
+        role_entry_t ssh_role;
+        mnemonic_state_t mnemonic_state;
+        key_store_t key_store;
+        dispatcher_ctx_t dispatcher;
+        char *sign_resp, *verify_resp;
+        const char *msg_hex = "68656c6c6f20776f726c64"; /* "hello world" */
+        char sign_req[512];
+        char verify_req[1024];
+        cJSON *sign_json, *result_item, *sig_item;
+        const char *sig_str = NULL;
+
+        role_table_init(&table);
+        ssh_role = make_ssh_ed25519_entry("ssh_main", 0);
+        role_table_add(&table, &ssh_role);
+
+        mnemonic_init(&mnemonic_state);
+        mnemonic_load(&mnemonic_state, mnemonic);
+
+        memset(&key_store, 0, sizeof(key_store));
+        alg_key_cache_init(&g_alg_key_cache);
+    alg_key_cache_init(&g_alg_key_cache);
+        crypto_derive_all(&key_store, &table, &mnemonic_state);
+        dispatcher_init(&dispatcher, &table, &mnemonic_state, &key_store, &g_alg_key_cache);
+
+        /* Sign */
+        snprintf(sign_req, sizeof(sign_req),
+                 "{\"id\":\"s1\",\"method\":\"sign_data\",\"params\":[\"%s\",{\"role\":\"ssh_main\"}]}",
+                 msg_hex);
+        sign_resp = dispatcher_handle_request(&dispatcher, sign_req);
+        check_condition("verify roundtrip: sign_data succeeds", sign_resp != NULL);
+
+        /* Extract signature from result */
+        if (sign_resp != NULL) {
+            sign_json = cJSON_Parse(sign_resp);
+            if (sign_json != NULL) {
+                result_item = cJSON_GetObjectItemCaseSensitive(sign_json, "result");
+                if (cJSON_IsString(result_item)) {
+                    cJSON *result_obj = cJSON_Parse(result_item->valuestring);
+                    if (result_obj != NULL) {
+                        sig_item = cJSON_GetObjectItemCaseSensitive(result_obj, "signature");
+                        if (cJSON_IsString(sig_item)) {
+                            sig_str = strdup(sig_item->valuestring);
+                        }
+                        cJSON_Delete(result_obj);
+                    }
+                }
+                cJSON_Delete(sign_json);
+            }
+        }
+        check_condition("verify roundtrip: extracted signature hex", sig_str != NULL);
+
+        /* Verify */
+        if (sig_str != NULL) {
+            snprintf(verify_req, sizeof(verify_req),
+                     "{\"id\":\"v1\",\"method\":\"verify_signature\",\"params\":[\"%s\",\"%s\",{\"role\":\"ssh_main\"}]}",
+                     msg_hex, sig_str);
+            verify_resp = dispatcher_handle_request(&dispatcher, verify_req);
+            check_condition("verify_signature returns valid:true",
+                            verify_resp != NULL && response_has(verify_resp, "valid") &&
+                            response_has(verify_resp, "true"));
+            free(verify_resp);
+
+            /* Verify with wrong message */
+            snprintf(verify_req, sizeof(verify_req),
+                     "{\"id\":\"v2\",\"method\":\"verify_signature\",\"params\":[\"00ff\",\"%s\",{\"role\":\"ssh_main\"}]}",
+                     sig_str);
+            verify_resp = dispatcher_handle_request(&dispatcher, verify_req);
+            check_condition("verify_signature wrong msg returns valid:false",
+                            verify_resp != NULL && response_has(verify_resp, "valid") &&
+                            response_has(verify_resp, "false"));
+            free(verify_resp);
+
+            free((void *)sig_str);
+        } else {
+            check_condition("verify_signature returns valid:true", 0);
+            check_condition("verify_signature wrong msg returns valid:false", 0);
+        }
+
+        free(sign_resp);
+        crypto_wipe(&key_store);
+        mnemonic_unload(&mnemonic_state);
+    }
+
+    printf("%d/%d tests passed\n", g_passes, g_total);
+    return (g_passes == g_total) ? 0 : 1;
+}

tests/test_enforcement.c

@@ -82,6 +82,8 @@ typedef enum {
     PURPOSE_SSH,
     PURPOSE_AGE,
     PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,      /* post-quantum signatures (ML-DSA, SLH-DSA) */
+    PURPOSE_PQ_KEM,      /* post-quantum key encapsulation (ML-KEM) */
     PURPOSE_UNKNOWN
 } role_purpose_t;
 
@@ -90,6 +92,9 @@ typedef enum {
     CURVE_SECP256K1 = 0,
     CURVE_ED25519,
     CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
     CURVE_UNKNOWN
 } role_curve_t;
 
@@ -195,6 +200,24 @@ const char *selector_strerror(int err);
 #define ENFORCE_ERR_PURPOSE      -1 /* purpose mismatch */
 #define ENFORCE_ERR_CURVE        -2 /* curve mismatch */
 #define ENFORCE_ERR_UNKNOWN_VERB -3 /* verb not recognized */
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
 
 /* Known verbs */
 #define VERB_SIGN_EVENT     "sign_event"
@@ -230,6 +253,8 @@ const char *enforce_strerror(int err);
 #define POLICY_MAX_PURPOSES   8
 #define POLICY_VERB_MAX_LEN   32
 #define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
 
 /* Prompt behavior */
 typedef enum {
@@ -254,6 +279,12 @@ typedef struct {
     int role_count;
     char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
     int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
     prompt_mode_t prompt;
     policy_source_t source;
 } policy_entry_t;
@@ -287,6 +318,20 @@ int policy_check(const policy_table_t *table, const char *caller_id,
                  const char *verb, const char *role_name, const char *purpose,
                  policy_source_t *out_source);
 
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
 /* Parse prompt mode from string */
 prompt_mode_t prompt_mode_from_str(const char *s);
 
@@ -294,15 +339,147 @@ prompt_mode_t prompt_mode_from_str(const char *s);
 const char *prompt_mode_to_str(prompt_mode_t m);
 
 
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,   /* existing, Nostr */
+    CRYPTO_ALG_ED25519,         /* new, SSH signatures */
+    CRYPTO_ALG_X25519,          /* new, key agreement */
+    CRYPTO_ALG_ML_DSA_65,       /* new, PQ signatures */
+    CRYPTO_ALG_SLH_DSA_128S,    /* new, PQ signatures */
+    CRYPTO_ALG_ML_KEM_768,      /* new, PQ KEM */
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;           /* 0 for KEM */
+    size_t ciphertext_len;    /* 0 for signatures */
+    size_t shared_secret_len; /* 0 for signatures */
+} crypto_alg_sizes_t;
+
+/* Get size info for an algorithm. Returns NULL for CRYPTO_ALG_UNKNOWN. */
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+
+/* Map role_curve_t + role_purpose_t to crypto_alg_t.
+ * Returns CRYPTO_ALG_UNKNOWN for unsupported combinations. */
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+
+/* Convert crypto_alg_t to string. Returns NULL for unknown. */
+const char *crypto_alg_to_str(crypto_alg_t alg);
+
+/* Parse string to crypto_alg_t. Returns CRYPTO_ALG_UNKNOWN for unrecognized. */
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+
+
 /* from crypto.h */
 
 
 /* Per-role derived key material (stored in secure memory) */
 typedef struct {
-    secure_buf_t private_key;  /* 32 bytes, mlock'd */
-    unsigned char public_key[32];
-    char pubkey_hex[65];       /* 64 hex chars + null */
-    char npub[128];            /* bech32 npub */
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
     int valid;
 } derived_key_t;
 
@@ -333,6 +510,82 @@ char *crypto_sign_event(const key_store_t *store, int role_index, const char *ev
 void crypto_wipe(key_store_t *store);
 
 
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
 /* from dispatcher.h */
 
 
@@ -341,10 +594,11 @@ typedef struct {
     role_table_t *role_table;
     mnemonic_state_t *mnemonic;
     key_store_t *key_store;
+    algorithm_key_cache_t *alg_key_cache;  /* algorithm-based on-demand keys */
 } dispatcher_ctx_t;
 
 /* Initialize dispatcher context */
-void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store);
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
 
 /*
  * Process a JSON-RPC request string and produce a JSON-RPC response string.

tests/test_integration.c

@@ -84,6 +84,8 @@ typedef enum {
     PURPOSE_SSH,
     PURPOSE_AGE,
     PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,      /* post-quantum signatures (ML-DSA, SLH-DSA) */
+    PURPOSE_PQ_KEM,      /* post-quantum key encapsulation (ML-KEM) */
     PURPOSE_UNKNOWN
 } role_purpose_t;
 
@@ -92,6 +94,9 @@ typedef enum {
     CURVE_SECP256K1 = 0,
     CURVE_ED25519,
     CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
     CURVE_UNKNOWN
 } role_curve_t;
 
@@ -197,6 +202,24 @@ const char *selector_strerror(int err);
 #define ENFORCE_ERR_PURPOSE      -1 /* purpose mismatch */
 #define ENFORCE_ERR_CURVE        -2 /* curve mismatch */
 #define ENFORCE_ERR_UNKNOWN_VERB -3 /* verb not recognized */
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
 
 /* Known verbs */
 #define VERB_SIGN_EVENT     "sign_event"
@@ -232,6 +255,8 @@ const char *enforce_strerror(int err);
 #define POLICY_MAX_PURPOSES   8
 #define POLICY_VERB_MAX_LEN   32
 #define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
 
 /* Prompt behavior */
 typedef enum {
@@ -256,6 +281,12 @@ typedef struct {
     int role_count;
     char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
     int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
     prompt_mode_t prompt;
     policy_source_t source;
 } policy_entry_t;
@@ -289,6 +320,20 @@ int policy_check(const policy_table_t *table, const char *caller_id,
                  const char *verb, const char *role_name, const char *purpose,
                  policy_source_t *out_source);
 
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
 /* Parse prompt mode from string */
 prompt_mode_t prompt_mode_from_str(const char *s);
 
@@ -296,15 +341,147 @@ prompt_mode_t prompt_mode_from_str(const char *s);
 const char *prompt_mode_to_str(prompt_mode_t m);
 
 
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,   /* existing, Nostr */
+    CRYPTO_ALG_ED25519,         /* new, SSH signatures */
+    CRYPTO_ALG_X25519,          /* new, key agreement */
+    CRYPTO_ALG_ML_DSA_65,       /* new, PQ signatures */
+    CRYPTO_ALG_SLH_DSA_128S,    /* new, PQ signatures */
+    CRYPTO_ALG_ML_KEM_768,      /* new, PQ KEM */
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;           /* 0 for KEM */
+    size_t ciphertext_len;    /* 0 for signatures */
+    size_t shared_secret_len; /* 0 for signatures */
+} crypto_alg_sizes_t;
+
+/* Get size info for an algorithm. Returns NULL for CRYPTO_ALG_UNKNOWN. */
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+
+/* Map role_curve_t + role_purpose_t to crypto_alg_t.
+ * Returns CRYPTO_ALG_UNKNOWN for unsupported combinations. */
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+
+/* Convert crypto_alg_t to string. Returns NULL for unknown. */
+const char *crypto_alg_to_str(crypto_alg_t alg);
+
+/* Parse string to crypto_alg_t. Returns CRYPTO_ALG_UNKNOWN for unrecognized. */
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+
+
 /* from crypto.h */
 
 
 /* Per-role derived key material (stored in secure memory) */
 typedef struct {
-    secure_buf_t private_key;  /* 32 bytes, mlock'd */
-    unsigned char public_key[32];
-    char pubkey_hex[65];       /* 64 hex chars + null */
-    char npub[128];            /* bech32 npub */
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
     int valid;
 } derived_key_t;
 
@@ -335,6 +512,82 @@ char *crypto_sign_event(const key_store_t *store, int role_index, const char *ev
 void crypto_wipe(key_store_t *store);
 
 
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
 /* from dispatcher.h */
 
 
@@ -343,10 +596,11 @@ typedef struct {
     role_table_t *role_table;
     mnemonic_state_t *mnemonic;
     key_store_t *key_store;
+    algorithm_key_cache_t *alg_key_cache;  /* algorithm-based on-demand keys */
 } dispatcher_ctx_t;
 
 /* Initialize dispatcher context */
-void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store);
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
 
 /*
  * Process a JSON-RPC request string and produce a JSON-RPC response string.

tests/test_mine_event.c

@@ -0,0 +1,703 @@
+/* Test for mine_event verb (NIP-13 Proof-of-Work) */
+/* NSIGNER_HEADERLESS_DECLS_BEGIN */
+#include <stddef.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <cJSON.h>
+
+/* from secure_mem.h */
+
+typedef struct {
+    void *data;
+    size_t size;
+    int locked;
+} secure_buf_t;
+
+int secure_buf_alloc(secure_buf_t *buf, size_t size);
+void secure_buf_free(secure_buf_t *buf);
+void secure_memzero(void *ptr, size_t len);
+
+/* from mnemonic.h */
+
+#define MNEMONIC_MAX_LEN 256
+
+typedef struct {
+    secure_buf_t buf;
+    int loaded;
+    int word_count;
+} mnemonic_state_t;
+
+void mnemonic_init(mnemonic_state_t *state);
+int mnemonic_load(mnemonic_state_t *state, const char *phrase);
+void mnemonic_unload(mnemonic_state_t *state);
+int mnemonic_is_loaded(const mnemonic_state_t *state);
+const char *mnemonic_get_phrase(const mnemonic_state_t *state);
+int mnemonic_generate(int word_count, char *out, size_t out_len);
+
+/* from role_table.h */
+
+#define ROLE_NAME_MAX 64
+#define ROLE_PATH_MAX 128
+#define ROLE_PURPOSE_MAX 32
+#define ROLE_CURVE_MAX 16
+#define ROLE_PUBKEY_HEX_MAX 66
+#define ROLE_TABLE_MAX_ENTRIES 256
+
+typedef enum {
+    PURPOSE_NOSTR = 0,
+    PURPOSE_BITCOIN,
+    PURPOSE_SSH,
+    PURPOSE_AGE,
+    PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,      /* post-quantum signatures (ML-DSA, SLH-DSA) */
+    PURPOSE_PQ_KEM,      /* post-quantum key encapsulation (ML-KEM) */
+    PURPOSE_UNKNOWN
+} role_purpose_t;
+
+typedef enum {
+    CURVE_SECP256K1 = 0,
+    CURVE_ED25519,
+    CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
+    CURVE_UNKNOWN
+} role_curve_t;
+
+typedef enum {
+    SELECTOR_NOSTR_INDEX,
+    SELECTOR_ROLE_PATH
+} role_selector_type_t;
+
+typedef struct {
+    char name[ROLE_NAME_MAX];
+    char purpose_str[ROLE_PURPOSE_MAX];
+    char curve_str[ROLE_CURVE_MAX];
+    role_purpose_t purpose;
+    role_curve_t curve;
+    role_selector_type_t selector_type;
+    int nostr_index;
+    char role_path[ROLE_PATH_MAX];
+    char pubkey_hex[ROLE_PUBKEY_HEX_MAX];
+    int derived;
+} role_entry_t;
+
+typedef struct {
+    role_entry_t entries[ROLE_TABLE_MAX_ENTRIES];
+    int count;
+} role_table_t;
+
+void role_table_init(role_table_t *table);
+int role_table_add(role_table_t *table, const role_entry_t *entry);
+role_entry_t *role_table_find_by_name(role_table_t *table, const char *name);
+role_entry_t *role_table_find_by_nostr_index(role_table_t *table, int index);
+role_entry_t *role_table_find_by_path(role_table_t *table, const char *path);
+role_entry_t *role_table_get_default(role_table_t *table);
+role_purpose_t role_purpose_from_str(const char *s);
+role_curve_t role_curve_from_str(const char *s);
+const char *role_purpose_to_str(role_purpose_t p);
+const char *role_curve_to_str(role_curve_t c);
+int role_table_register_nostr_index(role_table_t *table, int nostr_index);
+
+/* from selector.h */
+
+#define SELECTOR_OK                 0
+#define SELECTOR_ERR_AMBIGUOUS     -1
+#define SELECTOR_ERR_NOT_FOUND     -2
+#define SELECTOR_ERR_NO_DEFAULT    -3
+
+typedef struct {
+    int has_role;
+    char role_name[ROLE_NAME_MAX];
+    int has_nostr_index;
+    int nostr_index;
+    int has_role_path;
+    char role_path[ROLE_PATH_MAX];
+} selector_request_t;
+
+void selector_request_init(selector_request_t *req);
+int selector_resolve(const selector_request_t *req, role_table_t *table, role_entry_t **out);
+const char *selector_strerror(int err);
+
+/* from enforcement.h */
+
+#define ENFORCE_OK                0
+#define ENFORCE_ERR_PURPOSE      -1
+#define ENFORCE_ERR_CURVE        -2
+#define ENFORCE_ERR_UNKNOWN_VERB -3
+
+#define VERB_SIGN_EVENT     "sign_event"
+#define VERB_GET_PUBLIC_KEY "get_public_key"
+#define VERB_NIP44_ENCRYPT  "nip44_encrypt"
+#define VERB_NIP44_DECRYPT  "nip44_decrypt"
+#define VERB_NIP04_ENCRYPT  "nip04_encrypt"
+#define VERB_NIP04_DECRYPT  "nip04_decrypt"
+#define VERB_MINE_EVENT     "mine_event"
+#define VERB_SIGN_DATA      "sign_data"
+#define VERB_VERIFY_SIG     "verify_signature"
+#define VERB_SSH_SIGN       "ssh_sign"
+#define VERB_KEM_ENCAPS     "kem_encapsulate"
+#define VERB_KEM_DECAPS     "kem_decapsulate"
+
+int enforce_verb_role(const char *verb, const role_entry_t *role);
+const char *enforce_strerror(int err);
+
+/* from policy.h */
+
+#define POLICY_MAX_ENTRIES    32
+#define POLICY_MAX_VERBS      16
+#define POLICY_MAX_ROLES      16
+#define POLICY_MAX_PURPOSES   8
+#define POLICY_VERB_MAX_LEN   32
+#define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
+
+typedef enum {
+    PROMPT_NEVER = 0,
+    PROMPT_FIRST_PER_BOOT,
+    PROMPT_EVERY_REQUEST,
+    PROMPT_DENY
+} prompt_mode_t;
+
+typedef enum {
+    POLICY_SOURCE_DEFAULT = 0,
+    POLICY_SOURCE_PREAPPROVE,
+    POLICY_SOURCE_SESSION_GRANT
+} policy_source_t;
+
+typedef struct {
+    char caller[POLICY_CALLER_MAX_LEN];
+    char verbs[POLICY_MAX_VERBS][POLICY_VERB_MAX_LEN];
+    int verb_count;
+    char roles[POLICY_MAX_ROLES][ROLE_NAME_MAX];
+    int role_count;
+    char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
+    int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
+    prompt_mode_t prompt;
+    policy_source_t source;
+} policy_entry_t;
+
+typedef struct {
+    policy_entry_t entries[POLICY_MAX_ENTRIES];
+    int count;
+} policy_table_t;
+
+#define POLICY_ALLOW     0
+#define POLICY_DENY     -1
+#define POLICY_PROMPT   -2
+#define POLICY_NO_MATCH -3
+
+void policy_table_init(policy_table_t *table);
+void policy_init_default(policy_table_t *table, uid_t owner_uid);
+int policy_table_add(policy_table_t *table, const policy_entry_t *entry);
+int policy_check(const policy_table_t *table, const char *caller_id,
+                 const char *verb, const char *role_name, const char *purpose,
+                 policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+prompt_mode_t prompt_mode_from_str(const char *s);
+const char *prompt_mode_to_str(prompt_mode_t m);
+
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,   /* existing, Nostr */
+    CRYPTO_ALG_ED25519,         /* new, SSH signatures */
+    CRYPTO_ALG_X25519,          /* new, key agreement */
+    CRYPTO_ALG_ML_DSA_65,       /* new, PQ signatures */
+    CRYPTO_ALG_SLH_DSA_128S,    /* new, PQ signatures */
+    CRYPTO_ALG_ML_KEM_768,      /* new, PQ KEM */
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;           /* 0 for KEM */
+    size_t ciphertext_len;    /* 0 for signatures */
+    size_t shared_secret_len; /* 0 for signatures */
+} crypto_alg_sizes_t;
+
+/* Get size info for an algorithm. Returns NULL for CRYPTO_ALG_UNKNOWN. */
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+
+/* Map role_curve_t + role_purpose_t to crypto_alg_t.
+ * Returns CRYPTO_ALG_UNKNOWN for unsupported combinations. */
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+
+/* Convert crypto_alg_t to string. Returns NULL for unknown. */
+const char *crypto_alg_to_str(crypto_alg_t alg);
+
+/* Parse string to crypto_alg_t. Returns CRYPTO_ALG_UNKNOWN for unrecognized. */
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+
+
+/* from crypto.h */
+
+
+/* Per-role derived key material (stored in secure memory) */
+typedef struct {
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
+    int valid;
+} derived_key_t;
+
+typedef struct {
+    derived_key_t keys[ROLE_TABLE_MAX_ENTRIES];
+    int count;
+} key_store_t;
+
+int crypto_derive_all(key_store_t *store, role_table_t *table, const mnemonic_state_t *mnemonic);
+int crypto_derive_one(key_store_t *store, role_table_t *table, const mnemonic_state_t *mnemonic, int role_index);
+const unsigned char *crypto_get_private_key(const key_store_t *store, int role_index);
+const char *crypto_get_pubkey_hex(const key_store_t *store, int role_index);
+char *crypto_sign_event(const key_store_t *store, int role_index, const char *event_json);
+char *crypto_mine_event(const key_store_t *store, int role_index,
+                        const char *event_json, int difficulty,
+                        int threads, int timeout_sec);
+char *crypto_nip44_encrypt(const key_store_t *store, int role_index,
+                           const char *recipient_pubkey_hex, const char *plaintext);
+char *crypto_nip44_decrypt(const key_store_t *store, int role_index,
+                           const char *sender_pubkey_hex, const char *ciphertext);
+char *crypto_nip04_encrypt(const key_store_t *store, int role_index,
+                           const char *recipient_pubkey_hex, const char *plaintext);
+char *crypto_nip04_decrypt(const key_store_t *store, int role_index,
+                           const char *sender_pubkey_hex, const char *ciphertext);
+void crypto_wipe(key_store_t *store);
+
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
+/* from dispatcher.h */
+
+typedef struct {
+    role_table_t *role_table;
+    mnemonic_state_t *mnemonic;
+    key_store_t *key_store;
+} dispatcher_ctx_t;
+
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
+char *dispatcher_handle_request(dispatcher_ctx_t *ctx, const char *json_request);
+
+/* NSIGNER_HEADERLESS_DECLS_END */
+
+#include <nostr_core/nostr_common.h>
+#include <nostr_core/nip013.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static int g_passes = 0;
+static int g_total = 0;
+
+static void check_condition(const char *name, int condition) {
+    g_total++;
+    if (condition) {
+        printf("PASS: %s\n", name);
+        g_passes++;
+    } else {
+        printf("FAIL: %s\n", name);
+    }
+}
+
+static int response_has(const char *response, const char *needle) {
+    return (response != NULL && needle != NULL && strstr(response, needle) != NULL);
+}
+
+/* Parse a dispatcher response and extract the result object (for mine_event).
+ * Returns a newly-allocated cJSON result object, or NULL on failure.
+ * Caller must delete the returned object. */
+static cJSON *extract_result_object(const char *response) {
+    cJSON *resp_json = NULL;
+    cJSON *result_str = NULL;
+    cJSON *result_obj = NULL;
+
+    if (response == NULL) return NULL;
+
+    resp_json = cJSON_Parse(response);
+    if (!resp_json) return NULL;
+
+    result_str = cJSON_GetObjectItemCaseSensitive(resp_json, "result");
+    if (!result_str || !cJSON_IsString(result_str)) {
+        cJSON_Delete(resp_json);
+        return NULL;
+    }
+
+    result_obj = cJSON_Parse(result_str->valuestring);
+    cJSON_Delete(resp_json);
+    return result_obj;
+}
+
+/* Check if target_reached in the result object matches expected */
+static int check_target_reached(const char *response, int expected) {
+    cJSON *result_obj = extract_result_object(response);
+    cJSON *tr;
+    int val = -1;
+
+    if (!result_obj) return 0;
+
+    tr = cJSON_GetObjectItemCaseSensitive(result_obj, "target_reached");
+    if (tr && cJSON_IsBool(tr)) {
+        val = cJSON_IsTrue(tr) ? 1 : 0;
+    }
+
+    cJSON_Delete(result_obj);
+    return (val == expected);
+}
+
+static role_entry_t make_nostr_entry(const char *name, int idx) {
+    role_entry_t e;
+    memset(&e, 0, sizeof(e));
+    strncpy(e.name, name, sizeof(e.name) - 1);
+    strncpy(e.purpose_str, "nostr", sizeof(e.purpose_str) - 1);
+    strncpy(e.curve_str, "secp256k1", sizeof(e.curve_str) - 1);
+    e.purpose = role_purpose_from_str(e.purpose_str);
+    e.curve = role_curve_from_str(e.curve_str);
+    e.selector_type = SELECTOR_NOSTR_INDEX;
+    e.nostr_index = idx;
+    e.derived = 0;
+    return e;
+}
+
+int main(void) {
+    role_table_t table;
+    role_entry_t main_role;
+    mnemonic_state_t mnemonic;
+    dispatcher_ctx_t dispatcher;
+    static key_store_t key_store;
+    static algorithm_key_cache_t alg_key_cache;
+    const char *valid_12 = "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about";
+    char *resp;
+    int derived;
+
+    role_table_init(&table);
+    main_role = make_nostr_entry("main", 0);
+    role_table_add(&table, &main_role);
+
+    mnemonic_init(&mnemonic);
+    mnemonic_load(&mnemonic, valid_12);
+
+    memset(&key_store, 0, sizeof(key_store));
+    alg_key_cache_init(&alg_key_cache);
+    dispatcher_init(&dispatcher, &table, &mnemonic, &key_store, &alg_key_cache);
+
+    derived = nostr_init();
+    check_condition("nostr_init succeeds", derived == 0);
+
+    derived = crypto_derive_all(&key_store, &table, &mnemonic);
+    check_condition("crypto_derive_all derives at least one key", derived >= 1);
+
+    /* 1. mine_event with low difficulty (2) and short timeout (5 sec) — should reach target */
+    resp = dispatcher_handle_request(&dispatcher,
+        "{\"id\":\"1\",\"method\":\"mine_event\",\"params\":["
+        "\"{\\\"kind\\\":1,\\\"content\\\":\\\"hello pow\\\",\\\"tags\\\":[]}\","
+        "{\"difficulty\":2,\"threads\":2,\"timeout_sec\":5}]}");
+    check_condition("mine_event low difficulty returns result object",
+        response_has(resp, "\"id\":\"1\"") && response_has(resp, "\"result\"") && response_has(resp, "achieved_difficulty"));
+    check_condition("mine_event low difficulty returns signed event with nonce tag",
+        response_has(resp, "nonce") && response_has(resp, "sig") && response_has(resp, "pubkey"));
+    check_condition("mine_event low difficulty target_reached is true",
+        check_target_reached(resp, 1));
+    free(resp);
+
+    /* 2. mine_event with high difficulty (30) and short timeout (2 sec) — should NOT reach target */
+    resp = dispatcher_handle_request(&dispatcher,
+        "{\"id\":\"2\",\"method\":\"mine_event\",\"params\":["
+        "\"{\\\"kind\\\":1,\\\"content\\\":\\\"hard pow\\\",\\\"tags\\\":[]}\","
+        "{\"difficulty\":30,\"threads\":4,\"timeout_sec\":2}]}");
+    check_condition("mine_event high difficulty returns result object",
+        response_has(resp, "\"id\":\"2\"") && response_has(resp, "\"result\"") && response_has(resp, "achieved_difficulty"));
+    check_condition("mine_event high difficulty target_reached is false",
+        check_target_reached(resp, 0));
+    check_condition("mine_event high difficulty still returns a signed event",
+        response_has(resp, "nonce") && response_has(resp, "sig"));
+    free(resp);
+
+    /* 3. mine_event with only timeout (no difficulty) — should mine for full duration */
+    resp = dispatcher_handle_request(&dispatcher,
+        "{\"id\":\"3\",\"method\":\"mine_event\",\"params\":["
+        "\"{\\\"kind\\\":1,\\\"content\\\":\\\"timeout only\\\",\\\"tags\\\":[]}\","
+        "{\"threads\":2,\"timeout_sec\":2}]}");
+    check_condition("mine_event timeout-only returns result",
+        response_has(resp, "\"id\":\"3\"") && response_has(resp, "\"result\"") && response_has(resp, "achieved_difficulty"));
+    check_condition("mine_event timeout-only target_reached is false (no target set)",
+        check_target_reached(resp, 0));
+    free(resp);
+
+    /* 4. mine_event with neither difficulty nor timeout — should error */
+    resp = dispatcher_handle_request(&dispatcher,
+        "{\"id\":\"4\",\"method\":\"mine_event\",\"params\":["
+        "\"{\\\"kind\\\":1,\\\"content\\\":\\\"no params\\\",\\\"tags\\\":[]}\","
+        "{\"threads\":2}]}");
+    check_condition("mine_event with no termination condition returns 1007",
+        response_has(resp, "\"id\":\"4\"") && response_has(resp, "\"code\":1007") && response_has(resp, "no_termination_condition"));
+    free(resp);
+
+    /* 5. mine_event with only difficulty (no timeout) — should use safety timeout and reach low target */
+    resp = dispatcher_handle_request(&dispatcher,
+        "{\"id\":\"5\",\"method\":\"mine_event\",\"params\":["
+        "\"{\\\"kind\\\":1,\\\"content\\\":\\\"difficulty only\\\",\\\"tags\\\":[]}\","
+        "{\"difficulty\":1,\"threads\":2}]}");
+    check_condition("mine_event difficulty-only returns result and reaches target",
+        response_has(resp, "\"id\":\"5\"") && response_has(resp, "\"result\"") && check_target_reached(resp, 1));
+    free(resp);
+
+    /* 6. mine_event with invalid event JSON */
+    resp = dispatcher_handle_request(&dispatcher,
+        "{\"id\":\"6\",\"method\":\"mine_event\",\"params\":["
+        "\"not valid json\","
+        "{\"difficulty\":1,\"timeout_sec\":2}]}");
+    check_condition("mine_event with invalid event returns error",
+        response_has(resp, "\"id\":\"6\"") && (response_has(resp, "\"code\":1008") || response_has(resp, "\"code\":-32602")));
+    free(resp);
+
+    /* 7. Verify the mined event's difficulty via nip013 validation */
+    {
+        cJSON *resp_json, *result_str, *result_obj, *event_str, *event_json, *id_item;
+        const char *id_hex;
+        int pow_diff;
+
+        resp = dispatcher_handle_request(&dispatcher,
+            "{\"id\":\"7\",\"method\":\"mine_event\",\"params\":["
+            "\"{\\\"kind\\\":1,\\\"content\\\":\\\"verify pow\\\",\\\"tags\\\":[]}\","
+            "{\"difficulty\":4,\"threads\":4,\"timeout_sec\":5}]}");
+
+        resp_json = cJSON_Parse(resp);
+        if (resp_json) {
+            result_str = cJSON_GetObjectItemCaseSensitive(resp_json, "result");
+            if (result_str && cJSON_IsString(result_str)) {
+                result_obj = cJSON_Parse(result_str->valuestring);
+                if (result_obj) {
+                    event_str = cJSON_GetObjectItemCaseSensitive(result_obj, "event");
+                    if (event_str && cJSON_IsString(event_str)) {
+                        event_json = cJSON_Parse(event_str->valuestring);
+                        if (event_json) {
+                            id_item = cJSON_GetObjectItemCaseSensitive(event_json, "id");
+                            if (id_item && cJSON_IsString(id_item)) {
+                                id_hex = cJSON_GetStringValue(id_item);
+                                pow_diff = nostr_calculate_pow_difficulty(id_hex);
+                                check_condition("mined event has difficulty >= 4",
+                                    pow_diff >= 4);
+                            } else {
+                                check_condition("mined event has difficulty >= 4", 0);
+                            }
+                            cJSON_Delete(event_json);
+                        } else {
+                            check_condition("mined event has difficulty >= 4", 0);
+                        }
+                    } else {
+                        check_condition("mined event has difficulty >= 4", 0);
+                    }
+                    cJSON_Delete(result_obj);
+                } else {
+                    check_condition("mined event has difficulty >= 4", 0);
+                }
+            } else {
+                check_condition("mined event has difficulty >= 4", 0);
+            }
+            cJSON_Delete(resp_json);
+        } else {
+            check_condition("mined event has difficulty >= 4", 0);
+        }
+        free(resp);
+    }
+
+    crypto_wipe(&key_store);
+    nostr_cleanup();
+
+    printf("%d/%d tests passed\n", g_passes, g_total);
+    return (g_passes == g_total) ? 0 : 1;
+}

tests/test_ml_dsa_65.c

@@ -0,0 +1,836 @@
+/* Test for Phase 3 ML-DSA-65 (FIPS 204) post-quantum signatures.
+ *
+ * Verifies:
+ *   - ML-DSA-65 keygen from seed: 1952-byte pub, 4032-byte priv
+ *   - ML-DSA-65 keygen determinism: same seed -> same keypair
+ *   - ML-DSA-65 sign/verify roundtrip: sign a message, verify passes
+ *   - ML-DSA-65 sign/verify with wrong message: verify fails
+ *   - ML-DSA-65 sign/verify with wrong key: verify fails
+ *   - DRBG determinism: same seed -> same randombytes output
+ *   - Integration: derive ML-DSA-65 key from mnemonic via crypto_derive_one,
+ *     sign data via sign_data verb through dispatcher, verify signature
+ *   - Enforcement: sign_data allowed on pq-sig+ml-dsa-65
+ */
+/* NSIGNER_HEADERLESS_DECLS_BEGIN */
+#include <stddef.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <cJSON.h>
+
+/* from secure_mem.h */
+
+
+typedef struct {
+    void *data;
+    size_t size;
+    int locked;
+} secure_buf_t;
+
+int secure_buf_alloc(secure_buf_t *buf, size_t size);
+void secure_buf_free(secure_buf_t *buf);
+void secure_memzero(void *ptr, size_t len);
+
+
+/* from mnemonic.h */
+
+
+#define MNEMONIC_MAX_LEN 256
+
+typedef struct {
+    secure_buf_t buf;
+    int loaded;
+    int word_count;
+} mnemonic_state_t;
+
+void mnemonic_init(mnemonic_state_t *state);
+int mnemonic_load(mnemonic_state_t *state, const char *phrase);
+void mnemonic_unload(mnemonic_state_t *state);
+int mnemonic_is_loaded(const mnemonic_state_t *state);
+const char *mnemonic_get_phrase(const mnemonic_state_t *state);
+int mnemonic_generate(int word_count, char *out, size_t out_len);
+
+
+/* from role_table.h */
+
+
+#define ROLE_NAME_MAX 64
+#define ROLE_PATH_MAX 128
+#define ROLE_PURPOSE_MAX 32
+#define ROLE_CURVE_MAX 16
+#define ROLE_PUBKEY_HEX_MAX 66
+#define ROLE_TABLE_MAX_ENTRIES 256
+
+typedef enum {
+    PURPOSE_NOSTR = 0,
+    PURPOSE_BITCOIN,
+    PURPOSE_SSH,
+    PURPOSE_AGE,
+    PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,
+    PURPOSE_PQ_KEM,
+    PURPOSE_UNKNOWN
+} role_purpose_t;
+
+typedef enum {
+    CURVE_SECP256K1 = 0,
+    CURVE_ED25519,
+    CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
+    CURVE_UNKNOWN
+} role_curve_t;
+
+typedef enum {
+    SELECTOR_NOSTR_INDEX,
+    SELECTOR_ROLE_PATH
+} role_selector_type_t;
+
+typedef struct {
+    char name[ROLE_NAME_MAX];
+    char purpose_str[ROLE_PURPOSE_MAX];
+    char curve_str[ROLE_CURVE_MAX];
+    role_purpose_t purpose;
+    role_curve_t curve;
+    role_selector_type_t selector_type;
+    int nostr_index;
+    char role_path[ROLE_PATH_MAX];
+    char pubkey_hex[ROLE_PUBKEY_HEX_MAX];
+    int derived;
+} role_entry_t;
+
+typedef struct {
+    role_entry_t entries[ROLE_TABLE_MAX_ENTRIES];
+    int count;
+} role_table_t;
+
+void role_table_init(role_table_t *table);
+int role_table_add(role_table_t *table, const role_entry_t *entry);
+role_entry_t *role_table_find_by_name(role_table_t *table, const char *name);
+role_purpose_t role_purpose_from_str(const char *s);
+role_curve_t role_curve_from_str(const char *s);
+const char *role_purpose_to_str(role_purpose_t p);
+const char *role_curve_to_str(role_curve_t c);
+
+
+/* from selector.h */
+
+
+#define SELECTOR_OK                 0
+#define SELECTOR_ERR_AMBIGUOUS     -1
+#define SELECTOR_ERR_NOT_FOUND     -2
+#define SELECTOR_ERR_NO_DEFAULT    -3
+
+typedef struct {
+    int has_role;
+    char role_name[ROLE_NAME_MAX];
+    int has_nostr_index;
+    int nostr_index;
+    int has_role_path;
+    char role_path[ROLE_PATH_MAX];
+} selector_request_t;
+
+void selector_request_init(selector_request_t *req);
+int selector_resolve(const selector_request_t *req, role_table_t *table, role_entry_t **out);
+const char *selector_strerror(int err);
+
+
+/* from enforcement.h */
+
+
+#define ENFORCE_OK                0
+#define ENFORCE_ERR_PURPOSE      -1
+#define ENFORCE_ERR_CURVE        -2
+#define ENFORCE_ERR_UNKNOWN_VERB -3
+
+#define VERB_SIGN_EVENT     "sign_event"
+#define VERB_GET_PUBLIC_KEY "get_public_key"
+#define VERB_NIP44_ENCRYPT  "nip44_encrypt"
+#define VERB_NIP44_DECRYPT  "nip44_decrypt"
+#define VERB_NIP04_ENCRYPT  "nip04_encrypt"
+#define VERB_NIP04_DECRYPT  "nip04_decrypt"
+#define VERB_MINE_EVENT     "mine_event"
+#define VERB_SIGN_DATA      "sign_data"
+#define VERB_VERIFY_SIG     "verify_signature"
+#define VERB_SSH_SIGN       "ssh_sign"
+#define VERB_KEM_ENCAPS     "kem_encapsulate"
+#define VERB_KEM_DECAPS     "kem_decapsulate"
+
+int enforce_verb_role(const char *verb, const role_entry_t *role);
+const char *enforce_strerror(int err);
+
+
+/* from policy.h */
+
+
+#define POLICY_MAX_ENTRIES    32
+#define POLICY_MAX_VERBS      16
+#define POLICY_MAX_ROLES      16
+#define POLICY_MAX_PURPOSES   8
+#define POLICY_VERB_MAX_LEN   32
+#define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
+
+typedef enum {
+    PROMPT_NEVER = 0,
+    PROMPT_FIRST_PER_BOOT,
+    PROMPT_EVERY_REQUEST,
+    PROMPT_DENY
+} prompt_mode_t;
+
+typedef enum {
+    POLICY_SOURCE_DEFAULT = 0,
+    POLICY_SOURCE_PREAPPROVE,
+    POLICY_SOURCE_SESSION_GRANT
+} policy_source_t;
+
+typedef struct {
+    char caller[POLICY_CALLER_MAX_LEN];
+    char verbs[POLICY_MAX_VERBS][POLICY_VERB_MAX_LEN];
+    int verb_count;
+    char roles[POLICY_MAX_ROLES][ROLE_NAME_MAX];
+    int role_count;
+    char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
+    int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
+    prompt_mode_t prompt;
+    policy_source_t source;
+} policy_entry_t;
+
+typedef struct {
+    policy_entry_t entries[POLICY_MAX_ENTRIES];
+    int count;
+} policy_table_t;
+
+#define POLICY_ALLOW     0
+#define POLICY_DENY     -1
+#define POLICY_PROMPT   -2
+#define POLICY_NO_MATCH -3
+
+void policy_table_init(policy_table_t *table);
+void policy_init_default(policy_table_t *table, uid_t owner_uid);
+int policy_table_add(policy_table_t *table, const policy_entry_t *entry);
+int policy_check(const policy_table_t *table, const char *caller_id,
+                 const char *verb, const char *role_name, const char *purpose,
+                 policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+prompt_mode_t prompt_mode_from_str(const char *s);
+const char *prompt_mode_to_str(prompt_mode_t m);
+
+
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,
+    CRYPTO_ALG_ED25519,
+    CRYPTO_ALG_X25519,
+    CRYPTO_ALG_ML_DSA_65,
+    CRYPTO_ALG_SLH_DSA_128S,
+    CRYPTO_ALG_ML_KEM_768,
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;
+    size_t ciphertext_len;
+    size_t shared_secret_len;
+} crypto_alg_sizes_t;
+
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+const char *crypto_alg_to_str(crypto_alg_t alg);
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+/* from crypto.h */
+
+
+/* Per-role derived key material (stored in secure memory) */
+typedef struct {
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
+    int valid;
+} derived_key_t;
+
+typedef struct {
+    derived_key_t keys[ROLE_TABLE_MAX_ENTRIES];
+    int count;
+} key_store_t;
+
+int crypto_derive_all(key_store_t *store, role_table_t *table, const mnemonic_state_t *mnemonic);
+int crypto_derive_one(key_store_t *store, role_table_t *table, const mnemonic_state_t *mnemonic, int role_index);
+const unsigned char *crypto_get_private_key(const key_store_t *store, int role_index);
+const char *crypto_get_pubkey_hex(const key_store_t *store, int role_index);
+char *crypto_sign_event(const key_store_t *store, int role_index, const char *event_json);
+void crypto_wipe(key_store_t *store);
+
+
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
+/* from dispatcher.h */
+
+
+typedef struct {
+    role_table_t *role_table;
+    mnemonic_state_t *mnemonic;
+    key_store_t *key_store;
+} dispatcher_ctx_t;
+
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
+char *dispatcher_handle_request(dispatcher_ctx_t *ctx, const char *json_request);
+
+
+/* NSIGNER_HEADERLESS_DECLS_END */
+
+static key_store_t g_key_store;
+
+static algorithm_key_cache_t g_alg_key_cache;
+
+#include <nostr_core/nostr_common.h>
+#include <nostr_core/utils.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* ML-DSA-65 key sizes (FIPS 204) */
+#define ML_DSA_65_PUBKEY_BYTES  1952
+#define ML_DSA_65_PRIVKEY_BYTES 4032
+#define ML_DSA_65_SIG_BYTES     3309
+
+static int g_passes = 0;
+static int g_total = 0;
+
+static void check_condition(const char *name, int condition) {
+    g_total++;
+    if (condition) {
+        printf("PASS: %s\n", name);
+        g_passes++;
+    } else {
+        printf("FAIL: %s\n", name);
+    }
+}
+
+static int response_has(const char *response, const char *needle) {
+    return (response != NULL && needle != NULL && strstr(response, needle) != NULL);
+}
+
+static role_entry_t make_pq_sig_ml_dsa_65_entry(const char *name, int idx) {
+    role_entry_t e;
+    memset(&e, 0, sizeof(e));
+    strncpy(e.name, name, sizeof(e.name) - 1);
+    strncpy(e.purpose_str, "pq-sig", sizeof(e.purpose_str) - 1);
+    strncpy(e.curve_str, "ml-dsa-65", sizeof(e.curve_str) - 1);
+    e.purpose = role_purpose_from_str(e.purpose_str);
+    e.curve = role_curve_from_str(e.curve_str);
+    e.selector_type = SELECTOR_NOSTR_INDEX;
+    e.nostr_index = idx;
+    e.derived = 0;
+    return e;
+}
+
+static role_entry_t make_nostr_secp_entry(const char *name, int idx) {
+    role_entry_t e;
+    memset(&e, 0, sizeof(e));
+    strncpy(e.name, name, sizeof(e.name) - 1);
+    strncpy(e.purpose_str, "nostr", sizeof(e.purpose_str) - 1);
+    strncpy(e.curve_str, "secp256k1", sizeof(e.curve_str) - 1);
+    e.purpose = role_purpose_from_str(e.purpose_str);
+    e.curve = role_curve_from_str(e.curve_str);
+    e.selector_type = SELECTOR_NOSTR_INDEX;
+    e.nostr_index = idx;
+    e.derived = 0;
+    return e;
+}
+
+int main(void) {
+    /* Test mnemonic (BIP-39 standard test vector). */
+    const char *mnemonic = "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about";
+    unsigned char seed[32];
+    unsigned char *priv1, *pub1, *priv2, *pub2;
+    unsigned char *sig;
+    size_t sig_len;
+    int rc;
+
+    /* Allocate key buffers on the heap (they're large) */
+    priv1 = (unsigned char *)malloc(ML_DSA_65_PRIVKEY_BYTES);
+    pub1 = (unsigned char *)malloc(ML_DSA_65_PUBKEY_BYTES);
+    priv2 = (unsigned char *)malloc(ML_DSA_65_PRIVKEY_BYTES);
+    pub2 = (unsigned char *)malloc(ML_DSA_65_PUBKEY_BYTES);
+    sig = (unsigned char *)malloc(ML_DSA_65_SIG_BYTES);
+
+    if (!priv1 || !pub1 || !priv2 || !pub2 || !sig) {
+        printf("FAIL: memory allocation\n");
+        return 1;
+    }
+
+    /* ---- DRBG determinism ---- */
+    {
+        unsigned char out1[64], out2[64];
+
+        memset(seed, 0x42, 32);
+        pq_drbg_init(seed, 32);
+        rc = pq_drbg_randombytes(out1, 64);
+        check_condition("DRBG randombytes succeeds", rc == 0);
+
+        pq_drbg_zeroize();
+
+        memset(seed, 0x42, 32);
+        pq_drbg_init(seed, 32);
+        rc = pq_drbg_randombytes(out2, 64);
+        check_condition("DRBG randombytes succeeds (2nd)", rc == 0);
+
+        check_condition("DRBG determinism (same seed -> same output)",
+                        memcmp(out1, out2, 64) == 0);
+
+        pq_drbg_zeroize();
+    }
+
+    /* ---- ML-DSA-65 keygen from seed ---- */
+    memset(seed, 0x42, 32);
+    rc = crypto_ml_dsa_65_keygen_from_seed(seed, 32, priv1, pub1);
+    check_condition("ML-DSA-65 keygen from seed succeeds", rc == 0);
+
+    /* Keygen determinism: same seed -> same keypair */
+    memset(seed, 0x42, 32);
+    rc = crypto_ml_dsa_65_keygen_from_seed(seed, 32, priv2, pub2);
+    check_condition("ML-DSA-65 keygen determinism (same seed -> same key)", rc == 0 &&
+                    memcmp(priv1, priv2, ML_DSA_65_PRIVKEY_BYTES) == 0 &&
+                    memcmp(pub1, pub2, ML_DSA_65_PUBKEY_BYTES) == 0);
+
+    /* Different seed -> different keypair */
+    memset(seed, 0x99, 32);
+    rc = crypto_ml_dsa_65_keygen_from_seed(seed, 32, priv2, pub2);
+    check_condition("ML-DSA-65 keygen different seed -> different key", rc == 0 &&
+                    memcmp(pub1, pub2, ML_DSA_65_PUBKEY_BYTES) != 0);
+
+    /* ---- ML-DSA-65 sign/verify roundtrip ---- */
+    memset(seed, 0x42, 32);
+    crypto_ml_dsa_65_keygen_from_seed(seed, 32, priv1, pub1);
+    {
+        const char *msg = "hello world";
+        sig_len = ML_DSA_65_SIG_BYTES;
+        rc = crypto_ml_dsa_65_sign(priv1, ML_DSA_65_PRIVKEY_BYTES,
+                                    (const unsigned char *)msg, strlen(msg),
+                                    sig, &sig_len);
+        check_condition("ML-DSA-65 sign succeeds", rc == 0 && sig_len > 0);
+
+        rc = crypto_ml_dsa_65_verify(pub1, ML_DSA_65_PUBKEY_BYTES,
+                                      (const unsigned char *)msg, strlen(msg),
+                                      sig, sig_len);
+        check_condition("ML-DSA-65 verify valid signature", rc == 0);
+
+        /* Wrong message should fail */
+        {
+            const char *wrong_msg = "hello worle";
+            rc = crypto_ml_dsa_65_verify(pub1, ML_DSA_65_PUBKEY_BYTES,
+                                          (const unsigned char *)wrong_msg, strlen(wrong_msg),
+                                          sig, sig_len);
+            check_condition("ML-DSA-65 verify wrong message -> invalid", rc == 1);
+        }
+
+        /* Wrong key should fail */
+        memset(seed, 0xAB, 32);
+        crypto_ml_dsa_65_keygen_from_seed(seed, 32, priv2, pub2);
+        rc = crypto_ml_dsa_65_verify(pub2, ML_DSA_65_PUBKEY_BYTES,
+                                      (const unsigned char *)msg, strlen(msg),
+                                      sig, sig_len);
+        check_condition("ML-DSA-65 verify wrong key -> invalid", rc == 1);
+    }
+
+    /* ---- Integration: derive ML-DSA-65 key via crypto_derive_one ---- */
+    {
+        role_table_t table;
+        role_entry_t pq_role;
+        static mnemonic_state_t mnemonic_state;
+            int derived;
+
+        role_table_init(&table);
+        pq_role = make_pq_sig_ml_dsa_65_entry("pq_main", 0);
+        role_table_add(&table, &pq_role);
+
+        mnemonic_init(&mnemonic_state);
+        mnemonic_load(&mnemonic_state, mnemonic);
+
+        memset(&g_key_store, 0, sizeof(g_key_store));
+        alg_key_cache_init(&g_alg_key_cache);
+        derived = crypto_derive_all(&g_key_store, &table, &mnemonic_state);
+        check_condition("crypto_derive_all derives ML-DSA-65 key", derived == 1);
+
+        {
+            const char *pub_hex = crypto_get_pubkey_hex(&g_key_store, 0);
+            /* 1952 bytes hex-encoded = 3904 hex chars + null */
+            check_condition("ML-DSA-65 derived pubkey hex is 3904 chars",
+                            pub_hex != NULL && strlen(pub_hex) == 3904);
+        }
+
+        {
+            const unsigned char *priv = crypto_get_private_key(&g_key_store, 0);
+            check_condition("ML-DSA-65 derived private key not NULL", priv != NULL);
+        }
+
+        /* Determinism: re-derive and check same key */
+        {
+            static key_store_t key_store2;
+            memset(&key_store2, 0, sizeof(key_store2));
+            crypto_derive_all(&key_store2, &table, &mnemonic_state);
+            {
+                const char *pub_hex1 = crypto_get_pubkey_hex(&g_key_store, 0);
+                const char *pub_hex2 = crypto_get_pubkey_hex(&key_store2, 0);
+                check_condition("ML-DSA-65 derivation determinism (same mnemonic -> same key)",
+                                pub_hex1 != NULL && pub_hex2 != NULL &&
+                                strcmp(pub_hex1, pub_hex2) == 0);
+            }
+            crypto_wipe(&key_store2);
+        }
+
+        crypto_wipe(&g_key_store);
+        mnemonic_unload(&mnemonic_state);
+    }
+
+    /* ---- Integration: sign_data via dispatcher ---- */
+    {
+        role_table_t table;
+        role_entry_t pq_role;
+        static mnemonic_state_t mnemonic_state;
+        dispatcher_ctx_t dispatcher;
+        char *resp;
+        const char *msg_hex = "68656c6c6f20776f726c64"; /* "hello world" in hex */
+        char request[512];
+
+        role_table_init(&table);
+        pq_role = make_pq_sig_ml_dsa_65_entry("pq_main", 0);
+        role_table_add(&table, &pq_role);
+
+        mnemonic_init(&mnemonic_state);
+        mnemonic_load(&mnemonic_state, mnemonic);
+
+        memset(&g_key_store, 0, sizeof(g_key_store));
+        alg_key_cache_init(&g_alg_key_cache);
+        crypto_derive_all(&g_key_store, &table, &mnemonic_state);
+
+        dispatcher_init(&dispatcher, &table, &mnemonic_state, &g_key_store, &g_alg_key_cache);
+
+        /* sign_data request */
+        snprintf(request, sizeof(request),
+                 "{\"id\":\"test1\",\"method\":\"sign_data\",\"params\":[\"%s\",{\"role\":\"pq_main\"}]}",
+                 msg_hex);
+        resp = dispatcher_handle_request(&dispatcher, request);
+        check_condition("sign_data via dispatcher returns result",
+                        resp != NULL && response_has(resp, "\"result\""));
+        check_condition("sign_data result contains signature",
+                        resp != NULL && response_has(resp, "signature"));
+        check_condition("sign_data result contains algorithm ml-dsa-65",
+                        resp != NULL && response_has(resp, "ml-dsa-65"));
+        free(resp);
+
+        crypto_wipe(&g_key_store);
+        mnemonic_unload(&mnemonic_state);
+    }
+
+    /* ---- Integration: verify_signature roundtrip via dispatcher ---- */
+    {
+        role_table_t table;
+        role_entry_t pq_role;
+        static mnemonic_state_t mnemonic_state;
+        dispatcher_ctx_t dispatcher;
+        char *sign_resp, *verify_resp;
+        const char *msg_hex = "68656c6c6f20776f726c64"; /* "hello world" */
+        char sign_req[512];
+        char verify_req[8192];
+        cJSON *sign_json, *result_item, *sig_item;
+        const char *sig_str = NULL;
+
+        role_table_init(&table);
+        pq_role = make_pq_sig_ml_dsa_65_entry("pq_main", 0);
+        role_table_add(&table, &pq_role);
+
+        mnemonic_init(&mnemonic_state);
+        mnemonic_load(&mnemonic_state, mnemonic);
+
+        memset(&g_key_store, 0, sizeof(g_key_store));
+        alg_key_cache_init(&g_alg_key_cache);
+        crypto_derive_all(&g_key_store, &table, &mnemonic_state);
+        dispatcher_init(&dispatcher, &table, &mnemonic_state, &g_key_store, &g_alg_key_cache);
+
+        /* Sign */
+        snprintf(sign_req, sizeof(sign_req),
+                 "{\"id\":\"s1\",\"method\":\"sign_data\",\"params\":[\"%s\",{\"role\":\"pq_main\"}]}",
+                 msg_hex);
+        sign_resp = dispatcher_handle_request(&dispatcher, sign_req);
+        check_condition("verify roundtrip: sign_data succeeds", sign_resp != NULL);
+
+        /* Extract signature from result */
+        if (sign_resp != NULL) {
+            sign_json = cJSON_Parse(sign_resp);
+            if (sign_json != NULL) {
+                result_item = cJSON_GetObjectItemCaseSensitive(sign_json, "result");
+                if (cJSON_IsString(result_item)) {
+                    cJSON *result_obj = cJSON_Parse(result_item->valuestring);
+                    if (result_obj != NULL) {
+                        sig_item = cJSON_GetObjectItemCaseSensitive(result_obj, "signature");
+                        if (cJSON_IsString(sig_item)) {
+                            sig_str = strdup(sig_item->valuestring);
+                        }
+                        cJSON_Delete(result_obj);
+                    }
+                }
+                cJSON_Delete(sign_json);
+            }
+        }
+        check_condition("verify roundtrip: extracted signature hex", sig_str != NULL);
+
+        /* Verify */
+        if (sig_str != NULL) {
+            snprintf(verify_req, sizeof(verify_req),
+                     "{\"id\":\"v1\",\"method\":\"verify_signature\",\"params\":[\"%s\",\"%s\",{\"role\":\"pq_main\"}]}",
+                     msg_hex, sig_str);
+            verify_resp = dispatcher_handle_request(&dispatcher, verify_req);
+            check_condition("verify_signature returns valid:true",
+                            verify_resp != NULL && response_has(verify_resp, "valid") &&
+                            response_has(verify_resp, "true"));
+            free(verify_resp);
+
+            /* Verify with wrong message */
+            snprintf(verify_req, sizeof(verify_req),
+                     "{\"id\":\"v2\",\"method\":\"verify_signature\",\"params\":[\"00ff\",\"%s\",{\"role\":\"pq_main\"}]}",
+                     sig_str);
+            verify_resp = dispatcher_handle_request(&dispatcher, verify_req);
+            check_condition("verify_signature wrong msg returns valid:false",
+                            verify_resp != NULL && response_has(verify_resp, "valid") &&
+                            response_has(verify_resp, "false"));
+            free(verify_resp);
+
+            free((void *)sig_str);
+        } else {
+            check_condition("verify_signature returns valid:true", 0);
+            check_condition("verify_signature wrong msg returns valid:false", 0);
+        }
+
+        free(sign_resp);
+        crypto_wipe(&g_key_store);
+        mnemonic_unload(&mnemonic_state);
+    }
+
+    /* ---- Enforcement: sign_data on pq-sig+ml-dsa-65 ---- */
+    {
+        role_entry_t pq_sig = make_pq_sig_ml_dsa_65_entry("pq", 0);
+        role_entry_t nostr_secp = make_nostr_secp_entry("nostr", 0);
+
+        check_condition("enforce sign_data + pq-sig/ml-dsa-65 -> OK",
+                        enforce_verb_role(VERB_SIGN_DATA, &pq_sig) == ENFORCE_OK);
+
+        check_condition("enforce sign_data + nostr/secp256k1 -> PURPOSE err",
+                        enforce_verb_role(VERB_SIGN_DATA, &nostr_secp) == ENFORCE_ERR_PURPOSE);
+
+        check_condition("enforce verify_signature + pq-sig/ml-dsa-65 -> OK",
+                        enforce_verb_role(VERB_VERIFY_SIG, &pq_sig) == ENFORCE_OK);
+
+        check_condition("enforce sign_event + pq-sig/ml-dsa-65 -> PURPOSE err",
+                        enforce_verb_role(VERB_SIGN_EVENT, &pq_sig) == ENFORCE_ERR_PURPOSE);
+    }
+
+    /* Cleanup */
+    free(priv1);
+    free(pub1);
+    free(priv2);
+    free(pub2);
+    free(sig);
+
+    printf("%d/%d tests passed\n", g_passes, g_total);
+    return (g_passes == g_total) ? 0 : 1;
+}

tests/test_ml_kem_768.c

@@ -0,0 +1,668 @@
+/* Test for Phase 5 ML-KEM-768 (FIPS 203) post-quantum key encapsulation.
+ *
+ * Verifies:
+ *   - ML-KEM-768 keygen from seed: 1184-byte pub, 2400-byte priv
+ *   - ML-KEM-768 keygen determinism: same seed -> same keypair
+ *   - Encaps/decaps roundtrip: shared secrets match
+ *   - Encaps produces different ciphertexts each call (non-deterministic)
+ *   - Decaps with wrong ciphertext: different shared secret (implicit rejection)
+ *   - Integration: derive ML-KEM-768 key from mnemonic, encaps via dispatcher,
+ *     decaps via dispatcher, shared secrets match
+ *   - Enforcement: kem_encapsulate/kem_decapsulate allowed on pq-kem+ml-kem-768
+ */
+/* NSIGNER_HEADERLESS_DECLS_BEGIN */
+#include <stddef.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <cJSON.h>
+
+/* from secure_mem.h */
+typedef struct {
+    void *data;
+    size_t size;
+    int locked;
+} secure_buf_t;
+
+int secure_buf_alloc(secure_buf_t *buf, size_t size);
+void secure_buf_free(secure_buf_t *buf);
+void secure_memzero(void *ptr, size_t len);
+
+/* from mnemonic.h */
+#define MNEMONIC_MAX_LEN 256
+typedef struct {
+    secure_buf_t buf;
+    int loaded;
+    int word_count;
+} mnemonic_state_t;
+
+void mnemonic_init(mnemonic_state_t *state);
+int mnemonic_load(mnemonic_state_t *state, const char *phrase);
+void mnemonic_unload(mnemonic_state_t *state);
+int mnemonic_is_loaded(const mnemonic_state_t *state);
+const char *mnemonic_get_phrase(const mnemonic_state_t *state);
+int mnemonic_generate(int word_count, char *out, size_t out_len);
+
+/* from role_table.h */
+#define ROLE_NAME_MAX 64
+#define ROLE_PATH_MAX 128
+#define ROLE_PURPOSE_MAX 32
+#define ROLE_CURVE_MAX 16
+#define ROLE_PUBKEY_HEX_MAX 66
+#define ROLE_TABLE_MAX_ENTRIES 256
+
+typedef enum {
+    PURPOSE_NOSTR = 0, PURPOSE_BITCOIN, PURPOSE_SSH, PURPOSE_AGE,
+    PURPOSE_FIPS, PURPOSE_PQ_SIG, PURPOSE_PQ_KEM, PURPOSE_UNKNOWN
+} role_purpose_t;
+
+typedef enum {
+    CURVE_SECP256K1 = 0, CURVE_ED25519, CURVE_X25519,
+    CURVE_ML_DSA_65, CURVE_SLH_DSA_128S, CURVE_ML_KEM_768, CURVE_UNKNOWN
+} role_curve_t;
+
+typedef enum { SELECTOR_NOSTR_INDEX, SELECTOR_ROLE_PATH } role_selector_type_t;
+
+typedef struct {
+    char name[ROLE_NAME_MAX];
+    char purpose_str[ROLE_PURPOSE_MAX];
+    char curve_str[ROLE_CURVE_MAX];
+    role_purpose_t purpose;
+    role_curve_t curve;
+    role_selector_type_t selector_type;
+    int nostr_index;
+    char role_path[ROLE_PATH_MAX];
+    char pubkey_hex[ROLE_PUBKEY_HEX_MAX];
+    int derived;
+} role_entry_t;
+
+typedef struct {
+    role_entry_t entries[ROLE_TABLE_MAX_ENTRIES];
+    int count;
+} role_table_t;
+
+void role_table_init(role_table_t *table);
+int role_table_add(role_table_t *table, const role_entry_t *entry);
+role_entry_t *role_table_find_by_name(role_table_t *table, const char *name);
+role_purpose_t role_purpose_from_str(const char *s);
+role_curve_t role_curve_from_str(const char *s);
+const char *role_purpose_to_str(role_purpose_t p);
+const char *role_curve_to_str(role_curve_t c);
+
+/* from selector.h */
+#define SELECTOR_OK 0
+#define SELECTOR_ERR_AMBIGUOUS -1
+#define SELECTOR_ERR_NOT_FOUND -2
+#define SELECTOR_ERR_NO_DEFAULT -3
+
+typedef struct {
+    int has_role;
+    char role_name[ROLE_NAME_MAX];
+    int has_nostr_index;
+    int nostr_index;
+    int has_role_path;
+    char role_path[ROLE_PATH_MAX];
+} selector_request_t;
+
+void selector_request_init(selector_request_t *req);
+int selector_resolve(const selector_request_t *req, role_table_t *table, role_entry_t **out);
+const char *selector_strerror(int err);
+
+/* from enforcement.h */
+#define ENFORCE_OK 0
+#define ENFORCE_ERR_PURPOSE -1
+#define ENFORCE_ERR_CURVE -2
+#define ENFORCE_ERR_UNKNOWN_VERB -3
+
+#define VERB_SIGN_EVENT     "sign_event"
+#define VERB_GET_PUBLIC_KEY "get_public_key"
+#define VERB_NIP44_ENCRYPT  "nip44_encrypt"
+#define VERB_NIP44_DECRYPT  "nip44_decrypt"
+#define VERB_NIP04_ENCRYPT  "nip04_encrypt"
+#define VERB_NIP04_DECRYPT  "nip04_decrypt"
+#define VERB_MINE_EVENT     "mine_event"
+#define VERB_SIGN_DATA      "sign_data"
+#define VERB_VERIFY_SIG     "verify_signature"
+#define VERB_SSH_SIGN       "ssh_sign"
+#define VERB_KEM_ENCAPS     "kem_encapsulate"
+#define VERB_KEM_DECAPS     "kem_decapsulate"
+
+int enforce_verb_role(const char *verb, const role_entry_t *role);
+const char *enforce_strerror(int err);
+
+/* from policy.h */
+#define POLICY_MAX_ENTRIES 32
+#define POLICY_MAX_VERBS 16
+#define POLICY_MAX_ROLES 16
+#define POLICY_MAX_PURPOSES 8
+#define POLICY_VERB_MAX_LEN 32
+#define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
+
+typedef enum { PROMPT_NEVER = 0, PROMPT_FIRST_PER_BOOT, PROMPT_EVERY_REQUEST, PROMPT_DENY } prompt_mode_t;
+typedef enum { POLICY_SOURCE_DEFAULT = 0, POLICY_SOURCE_PREAPPROVE, POLICY_SOURCE_SESSION_GRANT } policy_source_t;
+
+typedef struct {
+    char caller[POLICY_CALLER_MAX_LEN];
+    char verbs[POLICY_MAX_VERBS][POLICY_VERB_MAX_LEN];
+    int verb_count;
+    char roles[POLICY_MAX_ROLES][ROLE_NAME_MAX];
+    int role_count;
+    char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
+    int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
+    prompt_mode_t prompt;
+    policy_source_t source;
+} policy_entry_t;
+
+typedef struct {
+    policy_entry_t entries[POLICY_MAX_ENTRIES];
+    int count;
+} policy_table_t;
+
+#define POLICY_ALLOW 0
+#define POLICY_DENY -1
+#define POLICY_PROMPT -2
+#define POLICY_NO_MATCH -3
+
+void policy_table_init(policy_table_t *table);
+void policy_init_default(policy_table_t *table, uid_t owner_uid);
+int policy_table_add(policy_table_t *table, const policy_entry_t *entry);
+int policy_check(const policy_table_t *table, const char *caller_id, const char *verb, const char *role_name, const char *purpose, policy_source_t *out_source);
+prompt_mode_t prompt_mode_from_str(const char *s);
+const char *prompt_mode_to_str(prompt_mode_t m);
+
+/* from pq_crypto.h */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0, CRYPTO_ALG_ED25519, CRYPTO_ALG_X25519,
+    CRYPTO_ALG_ML_DSA_65, CRYPTO_ALG_SLH_DSA_128S, CRYPTO_ALG_ML_KEM_768,
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;
+    size_t ciphertext_len;
+    size_t shared_secret_len;
+} crypto_alg_sizes_t;
+
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+const char *crypto_alg_to_str(crypto_alg_t alg);
+crypto_alg_t crypto_alg_from_str(const char *s);
+
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len, unsigned char *priv_out, unsigned char *pub_out);
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len, const unsigned char *msg, size_t msg_len, unsigned char *sig_out, size_t *sig_out_len);
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len, const unsigned char *msg, size_t msg_len, const unsigned char *sig, size_t sig_len);
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len, unsigned char *priv_out, unsigned char *pub_out);
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len, const unsigned char *peer_pub, size_t pub_len, unsigned char *shared_out, size_t *shared_out_len);
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path, unsigned char *seed_out, size_t seed_out_len);
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len, unsigned char *priv_out, unsigned char *pub_out);
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len, const unsigned char *msg, size_t msg_len, unsigned char *sig_out, size_t *sig_out_len);
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len, const unsigned char *msg, size_t msg_len, const unsigned char *sig, size_t sig_len);
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len, unsigned char *priv_out, unsigned char *pub_out);
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len, const unsigned char *msg, size_t msg_len, unsigned char *sig_out, size_t *sig_out_len);
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len, const unsigned char *msg, size_t msg_len, const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic). */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len, unsigned char *priv_out, unsigned char *pub_out);
+/* ML-KEM-768: encapsulate. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len, unsigned char *ct_out, unsigned char *ss_out);
+/* ML-KEM-768: decapsulate. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len, const unsigned char *ct, size_t ct_len, unsigned char *ss_out);
+
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+/* from crypto.h */
+typedef struct {
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char npub[128];
+    crypto_alg_t alg;
+    int valid;
+} derived_key_t;
+
+typedef struct {
+    derived_key_t keys[ROLE_TABLE_MAX_ENTRIES];
+    int count;
+} key_store_t;
+
+int crypto_derive_all(key_store_t *store, role_table_t *table, const mnemonic_state_t *mnemonic);
+int crypto_derive_one(key_store_t *store, role_table_t *table, const mnemonic_state_t *mnemonic, int role_index);
+const unsigned char *crypto_get_private_key(const key_store_t *store, int role_index);
+const char *crypto_get_pubkey_hex(const key_store_t *store, int role_index);
+char *crypto_sign_event(const key_store_t *store, int role_index, const char *event_json);
+void crypto_wipe(key_store_t *store);
+
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
+/* from dispatcher.h */
+typedef struct {
+    role_table_t *role_table;
+    mnemonic_state_t *mnemonic;
+    key_store_t *key_store;
+} dispatcher_ctx_t;
+
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
+char *dispatcher_handle_request(dispatcher_ctx_t *ctx, const char *json_request);
+
+/* NSIGNER_HEADERLESS_DECLS_END */
+
+static key_store_t g_key_store;
+
+static algorithm_key_cache_t g_alg_key_cache;
+
+#include <nostr_core/nostr_common.h>
+#include <nostr_core/utils.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* ML-KEM-768 key sizes (FIPS 203) */
+#define ML_KEM_768_PUBKEY_BYTES  1184
+#define ML_KEM_768_PRIVKEY_BYTES 2400
+#define ML_KEM_768_CT_BYTES      1088
+#define ML_KEM_768_SS_BYTES      32
+
+static int g_passes = 0;
+static int g_total = 0;
+
+static void check_condition(const char *name, int condition) {
+    g_total++;
+    if (condition) {
+        printf("PASS: %s\n", name);
+        g_passes++;
+    } else {
+        printf("FAIL: %s\n", name);
+    }
+}
+
+static int response_has(const char *response, const char *needle) {
+    return (response != NULL && needle != NULL && strstr(response, needle) != NULL);
+}
+
+static role_entry_t make_pq_kem_ml_kem_768_entry(const char *name, int idx) {
+    role_entry_t e;
+    memset(&e, 0, sizeof(e));
+    strncpy(e.name, name, sizeof(e.name) - 1);
+    strncpy(e.purpose_str, "pq-kem", sizeof(e.purpose_str) - 1);
+    strncpy(e.curve_str, "ml-kem-768", sizeof(e.curve_str) - 1);
+    e.purpose = role_purpose_from_str(e.purpose_str);
+    e.curve = role_curve_from_str(e.curve_str);
+    e.selector_type = SELECTOR_NOSTR_INDEX;
+    e.nostr_index = idx;
+    e.derived = 0;
+    return e;
+}
+
+static role_entry_t make_nostr_secp_entry(const char *name, int idx) {
+    role_entry_t e;
+    memset(&e, 0, sizeof(e));
+    strncpy(e.name, name, sizeof(e.name) - 1);
+    strncpy(e.purpose_str, "nostr", sizeof(e.purpose_str) - 1);
+    strncpy(e.curve_str, "secp256k1", sizeof(e.curve_str) - 1);
+    e.purpose = role_purpose_from_str(e.purpose_str);
+    e.curve = role_curve_from_str(e.curve_str);
+    e.selector_type = SELECTOR_NOSTR_INDEX;
+    e.nostr_index = idx;
+    e.derived = 0;
+    return e;
+}
+
+int main(void) {
+    const char *mnemonic = "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about";
+    unsigned char seed[32];
+    unsigned char *priv1, *pub1, *priv2, *pub2;
+    unsigned char *ct1, *ct2, *ss1, *ss2, *ss3;
+    int rc;
+
+    priv1 = (unsigned char *)malloc(ML_KEM_768_PRIVKEY_BYTES);
+    pub1 = (unsigned char *)malloc(ML_KEM_768_PUBKEY_BYTES);
+    priv2 = (unsigned char *)malloc(ML_KEM_768_PRIVKEY_BYTES);
+    pub2 = (unsigned char *)malloc(ML_KEM_768_PUBKEY_BYTES);
+    ct1 = (unsigned char *)malloc(ML_KEM_768_CT_BYTES);
+    ct2 = (unsigned char *)malloc(ML_KEM_768_CT_BYTES);
+    ss1 = (unsigned char *)malloc(ML_KEM_768_SS_BYTES);
+    ss2 = (unsigned char *)malloc(ML_KEM_768_SS_BYTES);
+    ss3 = (unsigned char *)malloc(ML_KEM_768_SS_BYTES);
+
+    if (!priv1 || !pub1 || !priv2 || !pub2 || !ct1 || !ct2 || !ss1 || !ss2 || !ss3) {
+        printf("FAIL: memory allocation\n");
+        return 1;
+    }
+
+    /* ---- ML-KEM-768 keygen from seed ---- */
+    memset(seed, 0x42, 32);
+    rc = crypto_ml_kem_768_keygen_from_seed(seed, 32, priv1, pub1);
+    check_condition("ML-KEM-768 keygen from seed succeeds", rc == 0);
+
+    /* Keygen determinism: same seed -> same keypair */
+    memset(seed, 0x42, 32);
+    rc = crypto_ml_kem_768_keygen_from_seed(seed, 32, priv2, pub2);
+    check_condition("ML-KEM-768 keygen determinism (same seed -> same key)", rc == 0 &&
+                    memcmp(priv1, priv2, ML_KEM_768_PRIVKEY_BYTES) == 0 &&
+                    memcmp(pub1, pub2, ML_KEM_768_PUBKEY_BYTES) == 0);
+
+    /* Different seed -> different keypair */
+    memset(seed, 0x99, 32);
+    rc = crypto_ml_kem_768_keygen_from_seed(seed, 32, priv2, pub2);
+    check_condition("ML-KEM-768 keygen different seed -> different key", rc == 0 &&
+                    memcmp(pub1, pub2, ML_KEM_768_PUBKEY_BYTES) != 0);
+
+    /* ---- Encaps/decaps roundtrip ---- */
+    memset(seed, 0x42, 32);
+    crypto_ml_kem_768_keygen_from_seed(seed, 32, priv1, pub1);
+
+    rc = crypto_ml_kem_768_encaps(pub1, ML_KEM_768_PUBKEY_BYTES, ct1, ss1);
+    check_condition("ML-KEM-768 encaps succeeds", rc == 0);
+
+    rc = crypto_ml_kem_768_decaps(priv1, ML_KEM_768_PRIVKEY_BYTES, ct1, ML_KEM_768_CT_BYTES, ss2);
+    check_condition("ML-KEM-768 decaps succeeds", rc == 0);
+
+    check_condition("ML-KEM-768 encaps/decaps shared secrets match",
+                    memcmp(ss1, ss2, ML_KEM_768_SS_BYTES) == 0);
+
+    /* ---- Encaps produces different ciphertexts each call ---- */
+    rc = crypto_ml_kem_768_encaps(pub1, ML_KEM_768_PUBKEY_BYTES, ct2, ss3);
+    check_condition("ML-KEM-768 second encaps succeeds", rc == 0);
+    check_condition("ML-KEM-768 encaps produces different ciphertexts",
+                    memcmp(ct1, ct2, ML_KEM_768_CT_BYTES) != 0);
+
+    /* Decaps with second ciphertext also matches its shared secret */
+    {
+        unsigned char ss4[32];
+        crypto_ml_kem_768_decaps(priv1, ML_KEM_768_PRIVKEY_BYTES, ct2, ML_KEM_768_CT_BYTES, ss4);
+        check_condition("ML-KEM-768 second encaps/decaps shared secrets match",
+                        memcmp(ss3, ss4, ML_KEM_768_SS_BYTES) == 0);
+    }
+
+    /* ---- Decaps with wrong ciphertext: implicit rejection ---- */
+    {
+        ct1[0] ^= 0xFF;
+        rc = crypto_ml_kem_768_decaps(priv1, ML_KEM_768_PRIVKEY_BYTES, ct1, ML_KEM_768_CT_BYTES, ss3);
+        ct1[0] ^= 0xFF; /* restore */
+        check_condition("ML-KEM-768 decaps wrong ct succeeds (no crash)", rc == 0);
+        /* The shared secret should be different from the original (implicit rejection) */
+        check_condition("ML-KEM-768 wrong ct gives different shared secret",
+                        memcmp(ss1, ss3, ML_KEM_768_SS_BYTES) != 0);
+    }
+
+    /* ---- Integration: derive ML-KEM-768 key via crypto_derive_all ---- */
+    {
+        role_table_t table;
+        role_entry_t pq_role;
+        static mnemonic_state_t mnemonic_state;
+            int derived;
+
+        role_table_init(&table);
+        pq_role = make_pq_kem_ml_kem_768_entry("pq_kem", 0);
+        role_table_add(&table, &pq_role);
+
+        mnemonic_init(&mnemonic_state);
+        mnemonic_load(&mnemonic_state, mnemonic);
+
+        memset(&g_key_store, 0, sizeof(g_key_store));
+        alg_key_cache_init(&g_alg_key_cache);
+        derived = crypto_derive_all(&g_key_store, &table, &mnemonic_state);
+        check_condition("crypto_derive_all derives ML-KEM-768 key", derived == 1);
+
+        {
+            const char *pub_hex = crypto_get_pubkey_hex(&g_key_store, 0);
+            /* 1184 bytes hex-encoded = 2368 hex chars + null */
+            check_condition("ML-KEM-768 derived pubkey hex is 2368 chars",
+                            pub_hex != NULL && strlen(pub_hex) == 2368);
+        }
+
+        {
+            const unsigned char *priv = crypto_get_private_key(&g_key_store, 0);
+            check_condition("ML-KEM-768 derived private key not NULL", priv != NULL);
+        }
+
+        /* Determinism: re-derive and check same key */
+        {
+            static key_store_t key_store2;
+            memset(&key_store2, 0, sizeof(key_store2));
+            crypto_derive_all(&key_store2, &table, &mnemonic_state);
+            {
+                const char *pub_hex1 = crypto_get_pubkey_hex(&g_key_store, 0);
+                const char *pub_hex2 = crypto_get_pubkey_hex(&key_store2, 0);
+                check_condition("ML-KEM-768 derivation determinism",
+                                pub_hex1 != NULL && pub_hex2 != NULL &&
+                                strcmp(pub_hex1, pub_hex2) == 0);
+            }
+            crypto_wipe(&key_store2);
+        }
+
+        crypto_wipe(&g_key_store);
+        mnemonic_unload(&mnemonic_state);
+    }
+
+    /* ---- Integration: kem_encapsulate / kem_decapsulate via dispatcher ---- */
+    {
+        role_table_t table;
+        role_entry_t pq_role;
+        static mnemonic_state_t mnemonic_state;
+        dispatcher_ctx_t dispatcher;
+        char *encaps_resp, *decaps_resp;
+        const char *pub_hex;
+        char encaps_req[6000]; /* pub_hex is 2368 chars + JSON overhead */
+        char *decaps_req = (char *)malloc(6000);
+        cJSON *encaps_json, *result_item, *ct_item, *ss_item;
+        const char *ct_str = NULL, *ss_encaps_str = NULL;
+        const char *ss_decaps_str = NULL;
+
+        role_table_init(&table);
+        pq_role = make_pq_kem_ml_kem_768_entry("pq_kem", 0);
+        role_table_add(&table, &pq_role);
+
+        mnemonic_init(&mnemonic_state);
+        mnemonic_load(&mnemonic_state, mnemonic);
+
+        memset(&g_key_store, 0, sizeof(g_key_store));
+        alg_key_cache_init(&g_alg_key_cache);
+        crypto_derive_all(&g_key_store, &table, &mnemonic_state);
+        dispatcher_init(&dispatcher, &table, &mnemonic_state, &g_key_store, &g_alg_key_cache);
+
+        /* Get the public key hex for encaps */
+        pub_hex = crypto_get_pubkey_hex(&g_key_store, 0);
+        check_condition("dispatcher integration: pubkey available", pub_hex != NULL);
+
+        if (pub_hex != NULL && decaps_req != NULL) {
+            /* kem_encapsulate request */
+            snprintf(encaps_req, sizeof(encaps_req),
+                     "{\"id\":\"e1\",\"method\":\"kem_encapsulate\",\"params\":[\"%s\",{\"role\":\"pq_kem\"}]}",
+                     pub_hex);
+            encaps_resp = dispatcher_handle_request(&dispatcher, encaps_req);
+            check_condition("kem_encapsulate via dispatcher returns result",
+                            encaps_resp != NULL && response_has(encaps_resp, "\"result\""));
+            check_condition("kem_encapsulate result contains ciphertext",
+                            encaps_resp != NULL && response_has(encaps_resp, "ciphertext"));
+            check_condition("kem_encapsulate result contains shared_secret",
+                            encaps_resp != NULL && response_has(encaps_resp, "shared_secret"));
+            check_condition("kem_encapsulate result contains algorithm ml-kem-768",
+                            encaps_resp != NULL && response_has(encaps_resp, "ml-kem-768"));
+
+            /* Extract ciphertext and shared_secret from result */
+            if (encaps_resp != NULL) {
+                encaps_json = cJSON_Parse(encaps_resp);
+                if (encaps_json != NULL) {
+                    result_item = cJSON_GetObjectItemCaseSensitive(encaps_json, "result");
+                    if (cJSON_IsString(result_item)) {
+                        cJSON *result_obj = cJSON_Parse(result_item->valuestring);
+                        if (result_obj != NULL) {
+                            ct_item = cJSON_GetObjectItemCaseSensitive(result_obj, "ciphertext");
+                            ss_item = cJSON_GetObjectItemCaseSensitive(result_obj, "shared_secret");
+                            if (cJSON_IsString(ct_item)) ct_str = strdup(ct_item->valuestring);
+                            if (cJSON_IsString(ss_item)) ss_encaps_str = strdup(ss_item->valuestring);
+                            cJSON_Delete(result_obj);
+                        }
+                    }
+                    cJSON_Delete(encaps_json);
+                }
+            }
+            check_condition("kem_encapsulate: extracted ciphertext hex", ct_str != NULL);
+            check_condition("kem_encapsulate: extracted shared_secret hex", ss_encaps_str != NULL);
+
+            /* kem_decapsulate request */
+            if (ct_str != NULL) {
+                snprintf(decaps_req, 6000,
+                         "{\"id\":\"d1\",\"method\":\"kem_decapsulate\",\"params\":[\"%s\",{\"role\":\"pq_kem\"}]}",
+                         ct_str);
+                decaps_resp = dispatcher_handle_request(&dispatcher, decaps_req);
+                check_condition("kem_decapsulate via dispatcher returns result",
+                                decaps_resp != NULL && response_has(decaps_resp, "\"result\""));
+                check_condition("kem_decapsulate result contains shared_secret",
+                                decaps_resp != NULL && response_has(decaps_resp, "shared_secret"));
+
+                /* Extract shared_secret from decaps result */
+                if (decaps_resp != NULL) {
+                    cJSON *decaps_json = cJSON_Parse(decaps_resp);
+                    if (decaps_json != NULL) {
+                        cJSON *d_result = cJSON_GetObjectItemCaseSensitive(decaps_json, "result");
+                        if (cJSON_IsString(d_result)) {
+                            cJSON *d_obj = cJSON_Parse(d_result->valuestring);
+                            if (d_obj != NULL) {
+                                cJSON *d_ss = cJSON_GetObjectItemCaseSensitive(d_obj, "shared_secret");
+                                if (cJSON_IsString(d_ss)) ss_decaps_str = strdup(d_ss->valuestring);
+                                cJSON_Delete(d_obj);
+                            }
+                        }
+                        cJSON_Delete(decaps_json);
+                    }
+                }
+
+                /* Check shared secrets match */
+                if (ss_encaps_str != NULL && ss_decaps_str != NULL) {
+                    check_condition("dispatcher encaps/decaps shared secrets match",
+                                    strcmp(ss_encaps_str, ss_decaps_str) == 0);
+                } else {
+                    check_condition("dispatcher encaps/decaps shared secrets match", 0);
+                }
+
+                free((void *)ss_decaps_str);
+                free(decaps_resp);
+            } else {
+                check_condition("kem_decapsulate via dispatcher returns result", 0);
+                check_condition("kem_decapsulate result contains shared_secret", 0);
+                check_condition("dispatcher encaps/decaps shared secrets match", 0);
+            }
+
+            free((void *)ct_str);
+            free((void *)ss_encaps_str);
+        }
+
+        free(decaps_req);
+        free(encaps_resp);
+        crypto_wipe(&g_key_store);
+        mnemonic_unload(&mnemonic_state);
+    }
+
+    /* ---- Enforcement: kem_encapsulate/kem_decapsulate on pq-kem+ml-kem-768 ---- */
+    {
+        role_entry_t pq_kem = make_pq_kem_ml_kem_768_entry("pqk", 0);
+        role_entry_t nostr_secp = make_nostr_secp_entry("nostr", 0);
+
+        check_condition("enforce kem_encapsulate + pq-kem/ml-kem-768 -> OK",
+                        enforce_verb_role(VERB_KEM_ENCAPS, &pq_kem) == ENFORCE_OK);
+
+        check_condition("enforce kem_encapsulate + nostr/secp256k1 -> PURPOSE err",
+                        enforce_verb_role(VERB_KEM_ENCAPS, &nostr_secp) == ENFORCE_ERR_PURPOSE);
+
+        check_condition("enforce kem_decapsulate + pq-kem/ml-kem-768 -> OK",
+                        enforce_verb_role(VERB_KEM_DECAPS, &pq_kem) == ENFORCE_OK);
+
+        check_condition("enforce kem_decapsulate + nostr/secp256k1 -> PURPOSE err",
+                        enforce_verb_role(VERB_KEM_DECAPS, &nostr_secp) == ENFORCE_ERR_PURPOSE);
+    }
+
+    /* ---- Cleanup ---- */
+    free(priv1); free(pub1); free(priv2); free(pub2);
+    free(ct1); free(ct2); free(ss1); free(ss2); free(ss3);
+
+    printf("\n%d/%d tests passed\n", g_passes, g_total);
+    return (g_passes == g_total) ? 0 : 1;
+}

tests/test_mnemonic.c

@@ -82,6 +82,8 @@ typedef enum {
     PURPOSE_SSH,
     PURPOSE_AGE,
     PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,      /* post-quantum signatures (ML-DSA, SLH-DSA) */
+    PURPOSE_PQ_KEM,      /* post-quantum key encapsulation (ML-KEM) */
     PURPOSE_UNKNOWN
 } role_purpose_t;
 
@@ -90,6 +92,9 @@ typedef enum {
     CURVE_SECP256K1 = 0,
     CURVE_ED25519,
     CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
     CURVE_UNKNOWN
 } role_curve_t;
 
@@ -195,6 +200,24 @@ const char *selector_strerror(int err);
 #define ENFORCE_ERR_PURPOSE      -1 /* purpose mismatch */
 #define ENFORCE_ERR_CURVE        -2 /* curve mismatch */
 #define ENFORCE_ERR_UNKNOWN_VERB -3 /* verb not recognized */
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
 
 /* Known verbs */
 #define VERB_SIGN_EVENT     "sign_event"
@@ -230,6 +253,8 @@ const char *enforce_strerror(int err);
 #define POLICY_MAX_PURPOSES   8
 #define POLICY_VERB_MAX_LEN   32
 #define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
 
 /* Prompt behavior */
 typedef enum {
@@ -254,6 +279,12 @@ typedef struct {
     int role_count;
     char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
     int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
     prompt_mode_t prompt;
     policy_source_t source;
 } policy_entry_t;
@@ -287,6 +318,20 @@ int policy_check(const policy_table_t *table, const char *caller_id,
                  const char *verb, const char *role_name, const char *purpose,
                  policy_source_t *out_source);
 
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
 /* Parse prompt mode from string */
 prompt_mode_t prompt_mode_from_str(const char *s);
 
@@ -294,15 +339,147 @@ prompt_mode_t prompt_mode_from_str(const char *s);
 const char *prompt_mode_to_str(prompt_mode_t m);
 
 
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,   /* existing, Nostr */
+    CRYPTO_ALG_ED25519,         /* new, SSH signatures */
+    CRYPTO_ALG_X25519,          /* new, key agreement */
+    CRYPTO_ALG_ML_DSA_65,       /* new, PQ signatures */
+    CRYPTO_ALG_SLH_DSA_128S,    /* new, PQ signatures */
+    CRYPTO_ALG_ML_KEM_768,      /* new, PQ KEM */
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;           /* 0 for KEM */
+    size_t ciphertext_len;    /* 0 for signatures */
+    size_t shared_secret_len; /* 0 for signatures */
+} crypto_alg_sizes_t;
+
+/* Get size info for an algorithm. Returns NULL for CRYPTO_ALG_UNKNOWN. */
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+
+/* Map role_curve_t + role_purpose_t to crypto_alg_t.
+ * Returns CRYPTO_ALG_UNKNOWN for unsupported combinations. */
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+
+/* Convert crypto_alg_t to string. Returns NULL for unknown. */
+const char *crypto_alg_to_str(crypto_alg_t alg);
+
+/* Parse string to crypto_alg_t. Returns CRYPTO_ALG_UNKNOWN for unrecognized. */
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+
+
 /* from crypto.h */
 
 
 /* Per-role derived key material (stored in secure memory) */
 typedef struct {
-    secure_buf_t private_key;  /* 32 bytes, mlock'd */
-    unsigned char public_key[32];
-    char pubkey_hex[65];       /* 64 hex chars + null */
-    char npub[128];            /* bech32 npub */
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
     int valid;
 } derived_key_t;
 
@@ -333,6 +510,82 @@ char *crypto_sign_event(const key_store_t *store, int role_index, const char *ev
 void crypto_wipe(key_store_t *store);
 
 
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
 /* from dispatcher.h */
 
 
@@ -341,10 +594,11 @@ typedef struct {
     role_table_t *role_table;
     mnemonic_state_t *mnemonic;
     key_store_t *key_store;
+    algorithm_key_cache_t *alg_key_cache;  /* algorithm-based on-demand keys */
 } dispatcher_ctx_t;
 
 /* Initialize dispatcher context */
-void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store);
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
 
 /*
  * Process a JSON-RPC request string and produce a JSON-RPC response string.

tests/test_policy.c

@@ -82,6 +82,8 @@ typedef enum {
     PURPOSE_SSH,
     PURPOSE_AGE,
     PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,      /* post-quantum signatures (ML-DSA, SLH-DSA) */
+    PURPOSE_PQ_KEM,      /* post-quantum key encapsulation (ML-KEM) */
     PURPOSE_UNKNOWN
 } role_purpose_t;
 
@@ -90,6 +92,9 @@ typedef enum {
     CURVE_SECP256K1 = 0,
     CURVE_ED25519,
     CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
     CURVE_UNKNOWN
 } role_curve_t;
 
@@ -195,6 +200,24 @@ const char *selector_strerror(int err);
 #define ENFORCE_ERR_PURPOSE      -1 /* purpose mismatch */
 #define ENFORCE_ERR_CURVE        -2 /* curve mismatch */
 #define ENFORCE_ERR_UNKNOWN_VERB -3 /* verb not recognized */
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
 
 /* Known verbs */
 #define VERB_SIGN_EVENT     "sign_event"
@@ -230,6 +253,8 @@ const char *enforce_strerror(int err);
 #define POLICY_MAX_PURPOSES   8
 #define POLICY_VERB_MAX_LEN   32
 #define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
 
 /* Prompt behavior */
 typedef enum {
@@ -254,6 +279,12 @@ typedef struct {
     int role_count;
     char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
     int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
     prompt_mode_t prompt;
     policy_source_t source;
 } policy_entry_t;
@@ -293,6 +324,20 @@ int policy_check(const policy_table_t *table, const char *caller_id,
                  const char *verb, const char *role_name, const char *purpose,
                  policy_source_t *out_source);
 
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
 /* Parse prompt mode from string */
 prompt_mode_t prompt_mode_from_str(const char *s);
 
@@ -300,15 +345,147 @@ prompt_mode_t prompt_mode_from_str(const char *s);
 const char *prompt_mode_to_str(prompt_mode_t m);
 
 
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,   /* existing, Nostr */
+    CRYPTO_ALG_ED25519,         /* new, SSH signatures */
+    CRYPTO_ALG_X25519,          /* new, key agreement */
+    CRYPTO_ALG_ML_DSA_65,       /* new, PQ signatures */
+    CRYPTO_ALG_SLH_DSA_128S,    /* new, PQ signatures */
+    CRYPTO_ALG_ML_KEM_768,      /* new, PQ KEM */
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;           /* 0 for KEM */
+    size_t ciphertext_len;    /* 0 for signatures */
+    size_t shared_secret_len; /* 0 for signatures */
+} crypto_alg_sizes_t;
+
+/* Get size info for an algorithm. Returns NULL for CRYPTO_ALG_UNKNOWN. */
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+
+/* Map role_curve_t + role_purpose_t to crypto_alg_t.
+ * Returns CRYPTO_ALG_UNKNOWN for unsupported combinations. */
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+
+/* Convert crypto_alg_t to string. Returns NULL for unknown. */
+const char *crypto_alg_to_str(crypto_alg_t alg);
+
+/* Parse string to crypto_alg_t. Returns CRYPTO_ALG_UNKNOWN for unrecognized. */
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+
+
 /* from crypto.h */
 
 
 /* Per-role derived key material (stored in secure memory) */
 typedef struct {
-    secure_buf_t private_key;  /* 32 bytes, mlock'd */
-    unsigned char public_key[32];
-    char pubkey_hex[65];       /* 64 hex chars + null */
-    char npub[128];            /* bech32 npub */
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
     int valid;
 } derived_key_t;
 
@@ -339,6 +516,82 @@ char *crypto_sign_event(const key_store_t *store, int role_index, const char *ev
 void crypto_wipe(key_store_t *store);
 
 
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
 /* from dispatcher.h */
 
 
@@ -347,10 +600,11 @@ typedef struct {
     role_table_t *role_table;
     mnemonic_state_t *mnemonic;
     key_store_t *key_store;
+    algorithm_key_cache_t *alg_key_cache;  /* algorithm-based on-demand keys */
 } dispatcher_ctx_t;
 
 /* Initialize dispatcher context */
-void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store);
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
 
 /*
  * Process a JSON-RPC request string and produce a JSON-RPC response string.

tests/test_pq_crypto.c

@@ -0,0 +1,640 @@
+/* Test for the Phase 1 post-quantum algorithm registry (pq_crypto.c).
+ *
+ * Verifies:
+ *   - crypto_alg_from_role returns the correct algorithm for every valid
+ *     (curve, purpose) combination and CRYPTO_ALG_UNKNOWN for invalid ones.
+ *   - crypto_alg_get_sizes returns the FIPS/PQClean size constants for each
+ *     algorithm and NULL for CRYPTO_ALG_UNKNOWN.
+ *   - crypto_alg_to_str / crypto_alg_from_str roundtrip for all algorithms.
+ *   - role_purpose_from_str("pq-sig") == PURPOSE_PQ_SIG
+ *   - role_purpose_from_str("pq-kem") == PURPOSE_PQ_KEM
+ *   - role_curve_from_str("ml-dsa-65") == CURVE_ML_DSA_65
+ *   - role_curve_from_str("slh-dsa-128s") == CURVE_SLH_DSA_128S
+ *   - role_curve_from_str("ml-kem-768") == CURVE_ML_KEM_768
+ */
+/* NSIGNER_HEADERLESS_DECLS_BEGIN */
+#include <stddef.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <cJSON.h>
+
+/* from secure_mem.h */
+
+
+typedef struct {
+    void *data;
+    size_t size;
+    int locked;
+} secure_buf_t;
+
+int secure_buf_alloc(secure_buf_t *buf, size_t size);
+void secure_buf_free(secure_buf_t *buf);
+void secure_memzero(void *ptr, size_t len);
+
+
+/* from mnemonic.h */
+
+
+#define MNEMONIC_MAX_LEN 256
+
+typedef struct {
+    secure_buf_t buf;
+    int loaded;
+    int word_count;
+} mnemonic_state_t;
+
+void mnemonic_init(mnemonic_state_t *state);
+int mnemonic_load(mnemonic_state_t *state, const char *phrase);
+void mnemonic_unload(mnemonic_state_t *state);
+int mnemonic_is_loaded(const mnemonic_state_t *state);
+const char *mnemonic_get_phrase(const mnemonic_state_t *state);
+int mnemonic_generate(int word_count, char *out, size_t out_len);
+
+
+/* from role_table.h */
+
+
+#define ROLE_NAME_MAX 64
+#define ROLE_PATH_MAX 128
+#define ROLE_PURPOSE_MAX 32
+#define ROLE_CURVE_MAX 16
+#define ROLE_PUBKEY_HEX_MAX 66
+#define ROLE_TABLE_MAX_ENTRIES 256
+
+typedef enum {
+    PURPOSE_NOSTR = 0,
+    PURPOSE_BITCOIN,
+    PURPOSE_SSH,
+    PURPOSE_AGE,
+    PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,      /* post-quantum signatures (ML-DSA, SLH-DSA) */
+    PURPOSE_PQ_KEM,      /* post-quantum key encapsulation (ML-KEM) */
+    PURPOSE_UNKNOWN
+} role_purpose_t;
+
+typedef enum {
+    CURVE_SECP256K1 = 0,
+    CURVE_ED25519,
+    CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
+    CURVE_UNKNOWN
+} role_curve_t;
+
+typedef enum {
+    SELECTOR_NOSTR_INDEX,
+    SELECTOR_ROLE_PATH
+} role_selector_type_t;
+
+typedef struct {
+    char name[ROLE_NAME_MAX];
+    char purpose_str[ROLE_PURPOSE_MAX];
+    char curve_str[ROLE_CURVE_MAX];
+    role_purpose_t purpose;
+    role_curve_t curve;
+    role_selector_type_t selector_type;
+    int nostr_index;
+    char role_path[ROLE_PATH_MAX];
+    char pubkey_hex[ROLE_PUBKEY_HEX_MAX];
+    int derived;
+} role_entry_t;
+
+typedef struct {
+    role_entry_t entries[ROLE_TABLE_MAX_ENTRIES];
+    int count;
+} role_table_t;
+
+void role_table_init(role_table_t *table);
+int role_table_add(role_table_t *table, const role_entry_t *entry);
+role_entry_t *role_table_find_by_name(role_table_t *table, const char *name);
+role_entry_t *role_table_find_by_nostr_index(role_table_t *table, int index);
+role_entry_t *role_table_find_by_path(role_table_t *table, const char *path);
+role_entry_t *role_table_get_default(role_table_t *table);
+role_purpose_t role_purpose_from_str(const char *s);
+role_curve_t role_curve_from_str(const char *s);
+const char *role_purpose_to_str(role_purpose_t p);
+const char *role_curve_to_str(role_curve_t c);
+int role_table_register_nostr_index(role_table_t *table, int nostr_index);
+
+
+/* from selector.h */
+
+
+#define SELECTOR_OK                 0
+#define SELECTOR_ERR_AMBIGUOUS     -1
+#define SELECTOR_ERR_NOT_FOUND     -2
+#define SELECTOR_ERR_NO_DEFAULT    -3
+
+typedef struct {
+    int has_role;
+    char role_name[ROLE_NAME_MAX];
+    int has_nostr_index;
+    int nostr_index;
+    int has_role_path;
+    char role_path[ROLE_PATH_MAX];
+} selector_request_t;
+
+void selector_request_init(selector_request_t *req);
+int selector_resolve(const selector_request_t *req, role_table_t *table, role_entry_t **out);
+const char *selector_strerror(int err);
+
+
+/* from enforcement.h */
+
+
+#define ENFORCE_OK                0
+#define ENFORCE_ERR_PURPOSE      -1
+#define ENFORCE_ERR_CURVE        -2
+#define ENFORCE_ERR_UNKNOWN_VERB -3
+
+#define VERB_SIGN_EVENT     "sign_event"
+#define VERB_GET_PUBLIC_KEY "get_public_key"
+#define VERB_NIP44_ENCRYPT  "nip44_encrypt"
+#define VERB_NIP44_DECRYPT  "nip44_decrypt"
+#define VERB_NIP04_ENCRYPT  "nip04_encrypt"
+#define VERB_NIP04_DECRYPT  "nip04_decrypt"
+
+int enforce_verb_role(const char *verb, const role_entry_t *role);
+const char *enforce_strerror(int err);
+
+
+/* from policy.h */
+
+
+#define POLICY_MAX_ENTRIES    32
+#define POLICY_MAX_VERBS      16
+#define POLICY_MAX_ROLES      16
+#define POLICY_MAX_PURPOSES   8
+#define POLICY_VERB_MAX_LEN   32
+#define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
+
+typedef enum {
+    PROMPT_NEVER = 0,
+    PROMPT_FIRST_PER_BOOT,
+    PROMPT_EVERY_REQUEST,
+    PROMPT_DENY
+} prompt_mode_t;
+
+typedef enum {
+    POLICY_SOURCE_DEFAULT = 0,
+    POLICY_SOURCE_PREAPPROVE,
+    POLICY_SOURCE_SESSION_GRANT
+} policy_source_t;
+
+typedef struct {
+    char caller[POLICY_CALLER_MAX_LEN];
+    char verbs[POLICY_MAX_VERBS][POLICY_VERB_MAX_LEN];
+    int verb_count;
+    char roles[POLICY_MAX_ROLES][ROLE_NAME_MAX];
+    int role_count;
+    char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
+    int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
+    prompt_mode_t prompt;
+    policy_source_t source;
+} policy_entry_t;
+
+typedef struct {
+    policy_entry_t entries[POLICY_MAX_ENTRIES];
+    int count;
+} policy_table_t;
+
+#define POLICY_ALLOW     0
+#define POLICY_DENY     -1
+#define POLICY_PROMPT   -2
+#define POLICY_NO_MATCH -3
+
+void policy_table_init(policy_table_t *table);
+void policy_init_default(policy_table_t *table, uid_t owner_uid);
+int policy_table_add(policy_table_t *table, const policy_entry_t *entry);
+int policy_check(const policy_table_t *table, const char *caller_id,
+                 const char *verb, const char *role_name, const char *purpose,
+                 policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+prompt_mode_t prompt_mode_from_str(const char *s);
+const char *prompt_mode_to_str(prompt_mode_t m);
+
+
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,   /* existing, Nostr */
+    CRYPTO_ALG_ED25519,         /* new, SSH signatures */
+    CRYPTO_ALG_X25519,          /* new, key agreement */
+    CRYPTO_ALG_ML_DSA_65,       /* new, PQ signatures */
+    CRYPTO_ALG_SLH_DSA_128S,    /* new, PQ signatures */
+    CRYPTO_ALG_ML_KEM_768,      /* new, PQ KEM */
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;           /* 0 for KEM */
+    size_t ciphertext_len;    /* 0 for signatures */
+    size_t shared_secret_len; /* 0 for signatures */
+} crypto_alg_sizes_t;
+
+/* Get size info for an algorithm. Returns NULL for CRYPTO_ALG_UNKNOWN. */
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+
+/* Map role_curve_t + role_purpose_t to crypto_alg_t.
+ * Returns CRYPTO_ALG_UNKNOWN for unsupported combinations. */
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+
+/* Convert crypto_alg_t to string. Returns NULL for unknown. */
+const char *crypto_alg_to_str(crypto_alg_t alg);
+
+/* Parse string to crypto_alg_t. Returns CRYPTO_ALG_UNKNOWN for unrecognized. */
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+
+
+/* from crypto.h */
+
+
+/* Per-role derived key material (stored in secure memory) */
+typedef struct {
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
+    int valid;
+} derived_key_t;
+
+typedef struct {
+    derived_key_t keys[ROLE_TABLE_MAX_ENTRIES];
+    int count;
+} key_store_t;
+
+int crypto_derive_all(key_store_t *store, role_table_t *table, const mnemonic_state_t *mnemonic);
+int crypto_derive_one(key_store_t *store, role_table_t *table, const mnemonic_state_t *mnemonic, int role_index);
+const unsigned char *crypto_get_private_key(const key_store_t *store, int role_index);
+const char *crypto_get_pubkey_hex(const key_store_t *store, int role_index);
+char *crypto_sign_event(const key_store_t *store, int role_index, const char *event_json);
+void crypto_wipe(key_store_t *store);
+
+
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
+/* from dispatcher.h */
+
+
+typedef struct {
+    role_table_t *role_table;
+    mnemonic_state_t *mnemonic;
+    key_store_t *key_store;
+} dispatcher_ctx_t;
+
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store);
+char *dispatcher_handle_request(dispatcher_ctx_t *ctx, const char *json_request);
+
+
+/* NSIGNER_HEADERLESS_DECLS_END */
+
+#include <stdio.h>
+#include <string.h>
+
+static int g_failures = 0;
+
+static void check_condition(const char *name, int condition) {
+    if (condition) {
+        printf("PASS: %s\n", name);
+    } else {
+        printf("FAIL: %s\n", name);
+        g_failures++;
+    }
+}
+
+int main(void) {
+    const crypto_alg_sizes_t *sz;
+    crypto_alg_t alg;
+    const char *str;
+    crypto_alg_t back;
+
+    /* ---- crypto_alg_from_role: valid combinations ---- */
+    check_condition("secp256k1+nostr -> SECP256K1",
+        crypto_alg_from_role(CURVE_SECP256K1, PURPOSE_NOSTR) == CRYPTO_ALG_SECP256K1);
+    check_condition("ed25519+ssh -> ED25519",
+        crypto_alg_from_role(CURVE_ED25519, PURPOSE_SSH) == CRYPTO_ALG_ED25519);
+    check_condition("x25519+age -> X25519",
+        crypto_alg_from_role(CURVE_X25519, PURPOSE_AGE) == CRYPTO_ALG_X25519);
+    check_condition("ml-dsa-65+pq-sig -> ML_DSA_65",
+        crypto_alg_from_role(CURVE_ML_DSA_65, PURPOSE_PQ_SIG) == CRYPTO_ALG_ML_DSA_65);
+    check_condition("slh-dsa-128s+pq-sig -> SLH_DSA_128S",
+        crypto_alg_from_role(CURVE_SLH_DSA_128S, PURPOSE_PQ_SIG) == CRYPTO_ALG_SLH_DSA_128S);
+    check_condition("ml-kem-768+pq-kem -> ML_KEM_768",
+        crypto_alg_from_role(CURVE_ML_KEM_768, PURPOSE_PQ_KEM) == CRYPTO_ALG_ML_KEM_768);
+
+    /* ---- crypto_alg_from_role: invalid combinations ---- */
+    check_condition("secp256k1+ssh -> UNKNOWN",
+        crypto_alg_from_role(CURVE_SECP256K1, PURPOSE_SSH) == CRYPTO_ALG_UNKNOWN);
+    check_condition("ed25519+nostr -> UNKNOWN",
+        crypto_alg_from_role(CURVE_ED25519, PURPOSE_NOSTR) == CRYPTO_ALG_UNKNOWN);
+    check_condition("ml-dsa-65+pq-kem -> UNKNOWN (purpose mismatch)",
+        crypto_alg_from_role(CURVE_ML_DSA_65, PURPOSE_PQ_KEM) == CRYPTO_ALG_UNKNOWN);
+    check_condition("ml-kem-768+pq-sig -> UNKNOWN (purpose mismatch)",
+        crypto_alg_from_role(CURVE_ML_KEM_768, PURPOSE_PQ_SIG) == CRYPTO_ALG_UNKNOWN);
+    check_condition("unknown curve -> UNKNOWN",
+        crypto_alg_from_role(CURVE_UNKNOWN, PURPOSE_NOSTR) == CRYPTO_ALG_UNKNOWN);
+
+    /* ---- crypto_alg_get_sizes ---- */
+    sz = crypto_alg_get_sizes(CRYPTO_ALG_SECP256K1);
+    check_condition("sizes secp256k1 not NULL", sz != NULL);
+    check_condition("sizes secp256k1 priv=32 pub=32 sig=64",
+        sz != NULL && sz->priv_key_len == 32 && sz->pub_key_len == 32 && sz->sig_len == 64 &&
+        sz->ciphertext_len == 0 && sz->shared_secret_len == 0);
+
+    sz = crypto_alg_get_sizes(CRYPTO_ALG_ED25519);
+    check_condition("sizes ed25519 priv=32 pub=32 sig=64",
+        sz != NULL && sz->priv_key_len == 32 && sz->pub_key_len == 32 && sz->sig_len == 64);
+
+    sz = crypto_alg_get_sizes(CRYPTO_ALG_X25519);
+    check_condition("sizes x25519 priv=32 pub=32 shared=32 sig=0",
+        sz != NULL && sz->priv_key_len == 32 && sz->pub_key_len == 32 &&
+        sz->sig_len == 0 && sz->shared_secret_len == 32);
+
+    sz = crypto_alg_get_sizes(CRYPTO_ALG_ML_DSA_65);
+    check_condition("sizes ml-dsa-65 priv=4032 pub=1952 sig=3309",
+        sz != NULL && sz->priv_key_len == 4032 && sz->pub_key_len == 1952 &&
+        sz->sig_len == 3309 && sz->ciphertext_len == 0 && sz->shared_secret_len == 0);
+
+    sz = crypto_alg_get_sizes(CRYPTO_ALG_SLH_DSA_128S);
+    check_condition("sizes slh-dsa-128s priv=64 pub=32 sig=7856",
+        sz != NULL && sz->priv_key_len == 64 && sz->pub_key_len == 32 &&
+        sz->sig_len == 7856 && sz->ciphertext_len == 0 && sz->shared_secret_len == 0);
+
+    sz = crypto_alg_get_sizes(CRYPTO_ALG_ML_KEM_768);
+    check_condition("sizes ml-kem-768 priv=2400 pub=1184 ct=1088 shared=32",
+        sz != NULL && sz->priv_key_len == 2400 && sz->pub_key_len == 1184 &&
+        sz->sig_len == 0 && sz->ciphertext_len == 1088 && sz->shared_secret_len == 32);
+
+    sz = crypto_alg_get_sizes(CRYPTO_ALG_UNKNOWN);
+    check_condition("sizes UNKNOWN -> NULL", sz == NULL);
+
+    /* ---- crypto_alg_to_str / crypto_alg_from_str roundtrip ---- */
+    str = crypto_alg_to_str(CRYPTO_ALG_SECP256K1);
+    check_condition("to_str secp256k1", str != NULL && strcmp(str, "secp256k1") == 0);
+    str = crypto_alg_to_str(CRYPTO_ALG_ED25519);
+    check_condition("to_str ed25519", str != NULL && strcmp(str, "ed25519") == 0);
+    str = crypto_alg_to_str(CRYPTO_ALG_X25519);
+    check_condition("to_str x25519", str != NULL && strcmp(str, "x25519") == 0);
+    str = crypto_alg_to_str(CRYPTO_ALG_ML_DSA_65);
+    check_condition("to_str ml-dsa-65", str != NULL && strcmp(str, "ml-dsa-65") == 0);
+    str = crypto_alg_to_str(CRYPTO_ALG_SLH_DSA_128S);
+    check_condition("to_str slh-dsa-128s", str != NULL && strcmp(str, "slh-dsa-128s") == 0);
+    str = crypto_alg_to_str(CRYPTO_ALG_ML_KEM_768);
+    check_condition("to_str ml-kem-768", str != NULL && strcmp(str, "ml-kem-768") == 0);
+    check_condition("to_str UNKNOWN -> NULL", crypto_alg_to_str(CRYPTO_ALG_UNKNOWN) == NULL);
+
+    back = crypto_alg_from_str("secp256k1");
+    check_condition("from_str secp256k1", back == CRYPTO_ALG_SECP256K1);
+    back = crypto_alg_from_str("ed25519");
+    check_condition("from_str ed25519", back == CRYPTO_ALG_ED25519);
+    back = crypto_alg_from_str("x25519");
+    check_condition("from_str x25519", back == CRYPTO_ALG_X25519);
+    back = crypto_alg_from_str("ml-dsa-65");
+    check_condition("from_str ml-dsa-65", back == CRYPTO_ALG_ML_DSA_65);
+    back = crypto_alg_from_str("slh-dsa-128s");
+    check_condition("from_str slh-dsa-128s", back == CRYPTO_ALG_SLH_DSA_128S);
+    back = crypto_alg_from_str("ml-kem-768");
+    check_condition("from_str ml-kem-768", back == CRYPTO_ALG_ML_KEM_768);
+    back = crypto_alg_from_str("not-a-real-alg");
+    check_condition("from_str bogus -> UNKNOWN", back == CRYPTO_ALG_UNKNOWN);
+    back = crypto_alg_from_str(NULL);
+    check_condition("from_str NULL -> UNKNOWN", back == CRYPTO_ALG_UNKNOWN);
+
+    /* roundtrip via to_str then from_str for each algorithm */
+    alg = CRYPTO_ALG_SECP256K1;
+    check_condition("roundtrip secp256k1",
+        crypto_alg_from_str(crypto_alg_to_str(alg)) == alg);
+    alg = CRYPTO_ALG_ML_DSA_65;
+    check_condition("roundtrip ml-dsa-65",
+        crypto_alg_from_str(crypto_alg_to_str(alg)) == alg);
+    alg = CRYPTO_ALG_ML_KEM_768;
+    check_condition("roundtrip ml-kem-768",
+        crypto_alg_from_str(crypto_alg_to_str(alg)) == alg);
+
+    /* ---- role_purpose_from_str new values ---- */
+    check_condition("purpose from_str pq-sig -> PQ_SIG",
+        role_purpose_from_str("pq-sig") == PURPOSE_PQ_SIG);
+    check_condition("purpose from_str pq-kem -> PQ_KEM",
+        role_purpose_from_str("pq-kem") == PURPOSE_PQ_KEM);
+    check_condition("purpose to_str PQ_SIG -> pq-sig",
+        strcmp(role_purpose_to_str(PURPOSE_PQ_SIG), "pq-sig") == 0);
+    check_condition("purpose to_str PQ_KEM -> pq-kem",
+        strcmp(role_purpose_to_str(PURPOSE_PQ_KEM), "pq-kem") == 0);
+
+    /* ---- role_curve_from_str new values ---- */
+    check_condition("curve from_str ml-dsa-65 -> ML_DSA_65",
+        role_curve_from_str("ml-dsa-65") == CURVE_ML_DSA_65);
+    check_condition("curve from_str slh-dsa-128s -> SLH_DSA_128S",
+        role_curve_from_str("slh-dsa-128s") == CURVE_SLH_DSA_128S);
+    check_condition("curve from_str ml-kem-768 -> ML_KEM_768",
+        role_curve_from_str("ml-kem-768") == CURVE_ML_KEM_768);
+    check_condition("curve to_str ML_DSA_65 -> ml-dsa-65",
+        strcmp(role_curve_to_str(CURVE_ML_DSA_65), "ml-dsa-65") == 0);
+    check_condition("curve to_str SLH_DSA_128S -> slh-dsa-128s",
+        strcmp(role_curve_to_str(CURVE_SLH_DSA_128S), "slh-dsa-128s") == 0);
+    check_condition("curve to_str ML_KEM_768 -> ml-kem-768",
+        strcmp(role_curve_to_str(CURVE_ML_KEM_768), "ml-kem-768") == 0);
+
+    if (g_failures == 0) {
+        printf("\nALL TESTS PASSED\n");
+        return 0;
+    }
+    printf("\n%d TEST(S) FAILED\n", g_failures);
+    return 1;
+}

tests/test_pubkey_format.c

@@ -0,0 +1,814 @@
+/* Test for Phase 6 get_public_key response format (dispatcher.c).
+ *
+ * Verifies:
+ *   - secp256k1: get_public_key returns plain hex string (backward compat)
+ *   - secp256k1 with {"format":"structured"}: returns structured JSON
+ *   - ed25519: returns structured JSON with algorithm "ed25519"
+ *   - ML-DSA-65: returns structured JSON with algorithm "ml-dsa-65" and large pubkey
+ *   - ML-KEM-768: returns structured JSON with algorithm "ml-kem-768"
+ *   - Structured result contains algorithm, public_key, and key_id fields
+ *   - key_id is the first 16 hex chars of the public key
+ */
+/* NSIGNER_HEADERLESS_DECLS_BEGIN */
+#include <stddef.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <cJSON.h>
+
+/* from secure_mem.h */
+
+
+typedef struct {
+    void *data;
+    size_t size;
+    int locked;
+} secure_buf_t;
+
+int secure_buf_alloc(secure_buf_t *buf, size_t size);
+void secure_buf_free(secure_buf_t *buf);
+void secure_memzero(void *ptr, size_t len);
+
+
+/* from mnemonic.h */
+
+
+#define MNEMONIC_MAX_LEN 256
+
+typedef struct {
+    secure_buf_t buf;
+    int loaded;
+    int word_count;
+} mnemonic_state_t;
+
+void mnemonic_init(mnemonic_state_t *state);
+int mnemonic_load(mnemonic_state_t *state, const char *phrase);
+void mnemonic_unload(mnemonic_state_t *state);
+int mnemonic_is_loaded(const mnemonic_state_t *state);
+const char *mnemonic_get_phrase(const mnemonic_state_t *state);
+int mnemonic_generate(int word_count, char *out, size_t out_len);
+
+
+/* from role_table.h */
+
+
+#define ROLE_NAME_MAX 64
+#define ROLE_PATH_MAX 128
+#define ROLE_PURPOSE_MAX 32
+#define ROLE_CURVE_MAX 16
+#define ROLE_PUBKEY_HEX_MAX 66
+#define ROLE_TABLE_MAX_ENTRIES 256
+
+typedef enum {
+    PURPOSE_NOSTR = 0,
+    PURPOSE_BITCOIN,
+    PURPOSE_SSH,
+    PURPOSE_AGE,
+    PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,
+    PURPOSE_PQ_KEM,
+    PURPOSE_UNKNOWN
+} role_purpose_t;
+
+typedef enum {
+    CURVE_SECP256K1 = 0,
+    CURVE_ED25519,
+    CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
+    CURVE_UNKNOWN
+} role_curve_t;
+
+typedef enum {
+    SELECTOR_NOSTR_INDEX,
+    SELECTOR_ROLE_PATH
+} role_selector_type_t;
+
+typedef struct {
+    char name[ROLE_NAME_MAX];
+    char purpose_str[ROLE_PURPOSE_MAX];
+    char curve_str[ROLE_CURVE_MAX];
+    role_purpose_t purpose;
+    role_curve_t curve;
+    role_selector_type_t selector_type;
+    int nostr_index;
+    char role_path[ROLE_PATH_MAX];
+    char pubkey_hex[ROLE_PUBKEY_HEX_MAX];
+    int derived;
+} role_entry_t;
+
+typedef struct {
+    role_entry_t entries[ROLE_TABLE_MAX_ENTRIES];
+    int count;
+} role_table_t;
+
+void role_table_init(role_table_t *table);
+int role_table_add(role_table_t *table, const role_entry_t *entry);
+role_entry_t *role_table_find_by_name(role_table_t *table, const char *name);
+role_entry_t *role_table_find_by_nostr_index(role_table_t *table, int index);
+role_entry_t *role_table_find_by_path(role_table_t *table, const char *path);
+role_entry_t *role_table_get_default(role_table_t *table);
+role_purpose_t role_purpose_from_str(const char *s);
+role_curve_t role_curve_from_str(const char *s);
+const char *role_purpose_to_str(role_purpose_t p);
+const char *role_curve_to_str(role_curve_t c);
+int role_table_register_nostr_index(role_table_t *table, int nostr_index);
+
+
+/* from selector.h */
+
+
+#define SELECTOR_OK                 0
+#define SELECTOR_ERR_AMBIGUOUS     -1
+#define SELECTOR_ERR_NOT_FOUND     -2
+#define SELECTOR_ERR_NO_DEFAULT    -3
+
+typedef struct {
+    int has_role;
+    char role_name[ROLE_NAME_MAX];
+    int has_nostr_index;
+    int nostr_index;
+    int has_role_path;
+    char role_path[ROLE_PATH_MAX];
+} selector_request_t;
+
+void selector_request_init(selector_request_t *req);
+int selector_resolve(const selector_request_t *req, role_table_t *table, role_entry_t **out);
+const char *selector_strerror(int err);
+
+
+/* from enforcement.h */
+
+
+#define ENFORCE_OK                0
+#define ENFORCE_ERR_PURPOSE      -1
+#define ENFORCE_ERR_CURVE        -2
+#define ENFORCE_ERR_UNKNOWN_VERB -3
+
+#define VERB_SIGN_EVENT     "sign_event"
+#define VERB_GET_PUBLIC_KEY "get_public_key"
+#define VERB_NIP44_ENCRYPT  "nip44_encrypt"
+#define VERB_NIP44_DECRYPT  "nip44_decrypt"
+#define VERB_NIP04_ENCRYPT  "nip04_encrypt"
+#define VERB_NIP04_DECRYPT  "nip04_decrypt"
+#define VERB_MINE_EVENT     "mine_event"
+#define VERB_SIGN_DATA      "sign_data"
+#define VERB_VERIFY_SIG     "verify_signature"
+#define VERB_SSH_SIGN       "ssh_sign"
+#define VERB_KEM_ENCAPS     "kem_encapsulate"
+#define VERB_KEM_DECAPS     "kem_decapsulate"
+
+int enforce_verb_role(const char *verb, const role_entry_t *role);
+const char *enforce_strerror(int err);
+
+
+/* from policy.h */
+
+
+#define POLICY_MAX_ENTRIES    32
+#define POLICY_MAX_VERBS      16
+#define POLICY_MAX_ROLES      16
+#define POLICY_MAX_PURPOSES   8
+#define POLICY_VERB_MAX_LEN   32
+#define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
+
+typedef enum {
+    PROMPT_NEVER = 0,
+    PROMPT_FIRST_PER_BOOT,
+    PROMPT_EVERY_REQUEST,
+    PROMPT_DENY
+} prompt_mode_t;
+
+typedef enum {
+    POLICY_SOURCE_DEFAULT = 0,
+    POLICY_SOURCE_PREAPPROVE,
+    POLICY_SOURCE_SESSION_GRANT
+} policy_source_t;
+
+typedef struct {
+    char caller[POLICY_CALLER_MAX_LEN];
+    char verbs[POLICY_MAX_VERBS][POLICY_VERB_MAX_LEN];
+    int verb_count;
+    char roles[POLICY_MAX_ROLES][ROLE_NAME_MAX];
+    int role_count;
+    char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
+    int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
+    prompt_mode_t prompt;
+    policy_source_t source;
+} policy_entry_t;
+
+typedef struct {
+    policy_entry_t entries[POLICY_MAX_ENTRIES];
+    int count;
+} policy_table_t;
+
+#define POLICY_ALLOW     0
+#define POLICY_DENY     -1
+#define POLICY_PROMPT   -2
+#define POLICY_NO_MATCH -3
+
+void policy_table_init(policy_table_t *table);
+void policy_init_default(policy_table_t *table, uid_t owner_uid);
+int policy_table_add(policy_table_t *table, const policy_entry_t *entry);
+int policy_check(const policy_table_t *table, const char *caller_id,
+                 const char *verb, const char *role_name, const char *purpose,
+                 policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+prompt_mode_t prompt_mode_from_str(const char *s);
+const char *prompt_mode_to_str(prompt_mode_t m);
+
+
+/* from pq_crypto.h */
+
+
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,
+    CRYPTO_ALG_ED25519,
+    CRYPTO_ALG_X25519,
+    CRYPTO_ALG_ML_DSA_65,
+    CRYPTO_ALG_SLH_DSA_128S,
+    CRYPTO_ALG_ML_KEM_768,
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;
+    size_t ciphertext_len;
+    size_t shared_secret_len;
+} crypto_alg_sizes_t;
+
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+const char *crypto_alg_to_str(crypto_alg_t alg);
+crypto_alg_t crypto_alg_from_str(const char *s);
+
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+/* from crypto.h */
+
+
+typedef struct {
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char npub[128];
+    crypto_alg_t alg;
+    int valid;
+} derived_key_t;
+
+typedef struct {
+    derived_key_t keys[ROLE_TABLE_MAX_ENTRIES];
+    int count;
+} key_store_t;
+
+int crypto_derive_all(key_store_t *store, role_table_t *table, const mnemonic_state_t *mnemonic);
+int crypto_derive_one(key_store_t *store, role_table_t *table, const mnemonic_state_t *mnemonic, int role_index);
+const unsigned char *crypto_get_private_key(const key_store_t *store, int role_index);
+const char *crypto_get_pubkey_hex(const key_store_t *store, int role_index);
+char *crypto_sign_event(const key_store_t *store, int role_index, const char *event_json);
+void crypto_wipe(key_store_t *store);
+
+
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
+/* from dispatcher.h */
+
+
+typedef struct {
+    role_table_t *role_table;
+    mnemonic_state_t *mnemonic;
+    key_store_t *key_store;
+} dispatcher_ctx_t;
+
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
+char *dispatcher_handle_request(dispatcher_ctx_t *ctx, const char *json_request);
+
+
+/* NSIGNER_HEADERLESS_DECLS_END */
+
+static key_store_t g_key_store;
+
+static algorithm_key_cache_t g_alg_key_cache;
+
+#include <nostr_core/nostr_common.h>
+#include <nostr_core/utils.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static int g_passes = 0;
+static int g_total = 0;
+
+static void check_condition(const char *name, int condition) {
+    g_total++;
+    if (condition) {
+        printf("PASS: %s\n", name);
+        g_passes++;
+    } else {
+        printf("FAIL: %s\n", name);
+    }
+}
+
+static int response_has(const char *response, const char *needle) {
+    return (response != NULL && needle != NULL && strstr(response, needle) != NULL);
+}
+
+/* Parse the dispatcher response's "result" field. If result is a JSON string
+ * (plain hex), returns a newly-allocated copy of the string in *out_str and
+ * returns 1. If result is a JSON object serialized as a string, parses it into
+ * *out_obj and returns 2. Returns 0 on failure. Caller frees accordingly. */
+static int parse_result(const char *response, char **out_str, cJSON **out_obj) {
+    cJSON *root = NULL;
+    cJSON *result_item = NULL;
+    int ret = 0;
+
+    if (out_str != NULL) *out_str = NULL;
+    if (out_obj != NULL) *out_obj = NULL;
+
+    if (response == NULL) return 0;
+    root = cJSON_Parse(response);
+    if (root == NULL) return 0;
+    result_item = cJSON_GetObjectItemCaseSensitive(root, "result");
+    if (cJSON_IsString(result_item) && result_item->valuestring != NULL) {
+        /* Could be a plain hex string OR a serialized JSON object string. */
+        cJSON *maybe_obj = cJSON_Parse(result_item->valuestring);
+        if (maybe_obj != NULL && cJSON_IsObject(maybe_obj)) {
+            if (out_obj != NULL) {
+                *out_obj = maybe_obj;
+                maybe_obj = NULL;
+                ret = 2;
+            } else {
+                cJSON_Delete(maybe_obj);
+                ret = 0;
+            }
+        } else {
+            cJSON_Delete(maybe_obj);
+            if (out_str != NULL) {
+                *out_str = strdup(result_item->valuestring);
+                ret = 1;
+            }
+        }
+    }
+    cJSON_Delete(root);
+    return ret;
+}
+
+static role_entry_t make_entry(const char *name, const char *purpose_str,
+                                const char *curve_str, int idx) {
+    role_entry_t e;
+    memset(&e, 0, sizeof(e));
+    strncpy(e.name, name, sizeof(e.name) - 1);
+    strncpy(e.purpose_str, purpose_str, sizeof(e.purpose_str) - 1);
+    strncpy(e.curve_str, curve_str, sizeof(e.curve_str) - 1);
+    e.purpose = role_purpose_from_str(e.purpose_str);
+    e.curve = role_curve_from_str(e.curve_str);
+    e.selector_type = SELECTOR_NOSTR_INDEX;
+    e.nostr_index = idx;
+    e.derived = 0;
+    return e;
+}
+
+int main(void) {
+    const char *mnemonic = "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about";
+
+    if (nostr_init() != 0) {
+        fprintf(stderr, "nostr_init failed\n");
+        return 1;
+    }
+
+    /* ---- secp256k1: plain hex (backward compat) ---- */
+    {
+        role_table_t table;
+        role_entry_t nostr_role;
+        static mnemonic_state_t mnemonic_state;
+            dispatcher_ctx_t dispatcher;
+        char *resp = NULL;
+        char *result_str = NULL;
+        cJSON *result_obj = NULL;
+        int pr;
+
+        role_table_init(&table);
+        nostr_role = make_entry("main", "nostr", "secp256k1", 0);
+        role_table_add(&table, &nostr_role);
+
+        mnemonic_init(&mnemonic_state);
+        mnemonic_load(&mnemonic_state, mnemonic);
+
+        memset(&g_key_store, 0, sizeof(g_key_store));
+        alg_key_cache_init(&g_alg_key_cache);
+        crypto_derive_all(&g_key_store, &table, &mnemonic_state);
+        dispatcher_init(&dispatcher, &table, &mnemonic_state, &g_key_store, &g_alg_key_cache);
+
+        resp = dispatcher_handle_request(&dispatcher,
+                                          "{\"id\":\"1\",\"method\":\"get_public_key\",\"params\":[{\"role\":\"main\"}]}");
+        check_condition("secp256k1 get_public_key returns a response", resp != NULL);
+
+        pr = parse_result(resp, &result_str, &result_obj);
+        check_condition("secp256k1 get_public_key result is a plain string (not object)",
+                        pr == 1 && result_str != NULL);
+        check_condition("secp256k1 plain hex result is 64 hex chars",
+                        result_str != NULL && strlen(result_str) == 64);
+        check_condition("secp256k1 plain hex result has no 'algorithm' field",
+                        !response_has(resp, "algorithm"));
+
+        free(result_str);
+        cJSON_Delete(result_obj);
+        free(resp);
+        crypto_wipe(&g_key_store);
+        mnemonic_unload(&mnemonic_state);
+    }
+
+    /* ---- secp256k1 with format:structured ---- */
+    {
+        role_table_t table;
+        role_entry_t nostr_role;
+        static mnemonic_state_t mnemonic_state;
+        dispatcher_ctx_t dispatcher;
+        char *resp = NULL;
+        char *result_str = NULL;
+        cJSON *result_obj = NULL;
+        cJSON *alg_item = NULL;
+        cJSON *pk_item = NULL;
+        cJSON *kid_item = NULL;
+        int pr;
+
+        role_table_init(&table);
+        nostr_role = make_entry("main", "nostr", "secp256k1", 0);
+        role_table_add(&table, &nostr_role);
+
+        mnemonic_init(&mnemonic_state);
+        mnemonic_load(&mnemonic_state, mnemonic);
+
+        memset(&g_key_store, 0, sizeof(g_key_store));
+        alg_key_cache_init(&g_alg_key_cache);
+        crypto_derive_all(&g_key_store, &table, &mnemonic_state);
+        dispatcher_init(&dispatcher, &table, &mnemonic_state, &g_key_store, &g_alg_key_cache);
+
+        resp = dispatcher_handle_request(&dispatcher,
+                                          "{\"id\":\"2\",\"method\":\"get_public_key\",\"params\":[{\"role\":\"main\",\"format\":\"structured\"}]}");
+        check_condition("secp256k1 structured get_public_key returns a response", resp != NULL);
+
+        pr = parse_result(resp, &result_str, &result_obj);
+        check_condition("secp256k1 structured result is a JSON object",
+                        pr == 2 && result_obj != NULL);
+
+        if (result_obj != NULL) {
+            alg_item = cJSON_GetObjectItemCaseSensitive(result_obj, "algorithm");
+            pk_item = cJSON_GetObjectItemCaseSensitive(result_obj, "public_key");
+            kid_item = cJSON_GetObjectItemCaseSensitive(result_obj, "key_id");
+            check_condition("secp256k1 structured has algorithm=secp256k1",
+                            cJSON_IsString(alg_item) && strcmp(alg_item->valuestring, "secp256k1") == 0);
+            check_condition("secp256k1 structured has public_key (64 hex chars)",
+                            cJSON_IsString(pk_item) && strlen(pk_item->valuestring) == 64);
+            check_condition("secp256k1 structured has key_id (16 hex chars)",
+                            cJSON_IsString(kid_item) && strlen(kid_item->valuestring) == 16);
+            check_condition("secp256k1 key_id == first 16 chars of public_key",
+                            cJSON_IsString(pk_item) && cJSON_IsString(kid_item) &&
+                            strncmp(pk_item->valuestring, kid_item->valuestring, 16) == 0);
+        } else {
+            check_condition("secp256k1 structured has algorithm=secp256k1", 0);
+            check_condition("secp256k1 structured has public_key (64 hex chars)", 0);
+            check_condition("secp256k1 structured has key_id (16 hex chars)", 0);
+            check_condition("secp256k1 key_id == first 16 chars of public_key", 0);
+        }
+
+        free(result_str);
+        cJSON_Delete(result_obj);
+        free(resp);
+        crypto_wipe(&g_key_store);
+        mnemonic_unload(&mnemonic_state);
+    }
+
+    /* ---- ed25519: structured JSON ---- */
+    {
+        role_table_t table;
+        role_entry_t ssh_role;
+        static mnemonic_state_t mnemonic_state;
+        dispatcher_ctx_t dispatcher;
+        char *resp = NULL;
+        char *result_str = NULL;
+        cJSON *result_obj = NULL;
+        cJSON *alg_item = NULL;
+        cJSON *pk_item = NULL;
+        cJSON *kid_item = NULL;
+        int pr;
+
+        role_table_init(&table);
+        ssh_role = make_entry("ssh_main", "ssh", "ed25519", 0);
+        role_table_add(&table, &ssh_role);
+
+        mnemonic_init(&mnemonic_state);
+        mnemonic_load(&mnemonic_state, mnemonic);
+
+        memset(&g_key_store, 0, sizeof(g_key_store));
+        alg_key_cache_init(&g_alg_key_cache);
+        crypto_derive_all(&g_key_store, &table, &mnemonic_state);
+        dispatcher_init(&dispatcher, &table, &mnemonic_state, &g_key_store, &g_alg_key_cache);
+
+        resp = dispatcher_handle_request(&dispatcher,
+                                          "{\"id\":\"3\",\"method\":\"get_public_key\",\"params\":[{\"role\":\"ssh_main\"}]}");
+        check_condition("ed25519 get_public_key returns a response", resp != NULL);
+
+        pr = parse_result(resp, &result_str, &result_obj);
+        check_condition("ed25519 get_public_key result is a JSON object",
+                        pr == 2 && result_obj != NULL);
+
+        if (result_obj != NULL) {
+            alg_item = cJSON_GetObjectItemCaseSensitive(result_obj, "algorithm");
+            pk_item = cJSON_GetObjectItemCaseSensitive(result_obj, "public_key");
+            kid_item = cJSON_GetObjectItemCaseSensitive(result_obj, "key_id");
+            check_condition("ed25519 structured has algorithm=ed25519",
+                            cJSON_IsString(alg_item) && strcmp(alg_item->valuestring, "ed25519") == 0);
+            check_condition("ed25519 structured has public_key (64 hex chars)",
+                            cJSON_IsString(pk_item) && strlen(pk_item->valuestring) == 64);
+            check_condition("ed25519 structured has key_id (16 hex chars)",
+                            cJSON_IsString(kid_item) && strlen(kid_item->valuestring) == 16);
+            check_condition("ed25519 key_id == first 16 chars of public_key",
+                            cJSON_IsString(pk_item) && cJSON_IsString(kid_item) &&
+                            strncmp(pk_item->valuestring, kid_item->valuestring, 16) == 0);
+        } else {
+            check_condition("ed25519 structured has algorithm=ed25519", 0);
+            check_condition("ed25519 structured has public_key (64 hex chars)", 0);
+            check_condition("ed25519 structured has key_id (16 hex chars)", 0);
+            check_condition("ed25519 key_id == first 16 chars of public_key", 0);
+        }
+
+        free(result_str);
+        cJSON_Delete(result_obj);
+        free(resp);
+        crypto_wipe(&g_key_store);
+        mnemonic_unload(&mnemonic_state);
+    }
+
+    /* ---- ML-DSA-65: structured JSON with large pubkey ---- */
+    {
+        role_table_t table;
+        role_entry_t pq_role;
+        static mnemonic_state_t mnemonic_state;
+        dispatcher_ctx_t dispatcher;
+        char *resp = NULL;
+        char *result_str = NULL;
+        cJSON *result_obj = NULL;
+        cJSON *alg_item = NULL;
+        cJSON *pk_item = NULL;
+        cJSON *kid_item = NULL;
+        const crypto_alg_sizes_t *sz;
+        int pr;
+
+        role_table_init(&table);
+        pq_role = make_entry("pq_sig", "pq-sig", "ml-dsa-65", 0);
+        role_table_add(&table, &pq_role);
+
+        mnemonic_init(&mnemonic_state);
+        mnemonic_load(&mnemonic_state, mnemonic);
+
+        memset(&g_key_store, 0, sizeof(g_key_store));
+        alg_key_cache_init(&g_alg_key_cache);
+        crypto_derive_all(&g_key_store, &table, &mnemonic_state);
+        dispatcher_init(&dispatcher, &table, &mnemonic_state, &g_key_store, &g_alg_key_cache);
+
+        sz = crypto_alg_get_sizes(CRYPTO_ALG_ML_DSA_65);
+        check_condition("ML-DSA-65 sizes available", sz != NULL);
+
+        resp = dispatcher_handle_request(&dispatcher,
+                                          "{\"id\":\"4\",\"method\":\"get_public_key\",\"params\":[{\"role\":\"pq_sig\"}]}");
+        check_condition("ML-DSA-65 get_public_key returns a response", resp != NULL);
+
+        pr = parse_result(resp, &result_str, &result_obj);
+        check_condition("ML-DSA-65 get_public_key result is a JSON object",
+                        pr == 2 && result_obj != NULL);
+
+        if (result_obj != NULL && sz != NULL) {
+            alg_item = cJSON_GetObjectItemCaseSensitive(result_obj, "algorithm");
+            pk_item = cJSON_GetObjectItemCaseSensitive(result_obj, "public_key");
+            kid_item = cJSON_GetObjectItemCaseSensitive(result_obj, "key_id");
+            check_condition("ML-DSA-65 structured has algorithm=ml-dsa-65",
+                            cJSON_IsString(alg_item) && strcmp(alg_item->valuestring, "ml-dsa-65") == 0);
+            check_condition("ML-DSA-65 structured has large public_key (3904 hex chars)",
+                            cJSON_IsString(pk_item) && strlen(pk_item->valuestring) == sz->pub_key_len * 2);
+            check_condition("ML-DSA-65 structured has key_id (16 hex chars)",
+                            cJSON_IsString(kid_item) && strlen(kid_item->valuestring) == 16);
+            check_condition("ML-DSA-65 key_id == first 16 chars of public_key",
+                            cJSON_IsString(pk_item) && cJSON_IsString(kid_item) &&
+                            strncmp(pk_item->valuestring, kid_item->valuestring, 16) == 0);
+        } else {
+            check_condition("ML-DSA-65 structured has algorithm=ml-dsa-65", 0);
+            check_condition("ML-DSA-65 structured has large public_key (3904 hex chars)", 0);
+            check_condition("ML-DSA-65 structured has key_id (16 hex chars)", 0);
+            check_condition("ML-DSA-65 key_id == first 16 chars of public_key", 0);
+        }
+
+        free(result_str);
+        cJSON_Delete(result_obj);
+        free(resp);
+        crypto_wipe(&g_key_store);
+        mnemonic_unload(&mnemonic_state);
+    }
+
+    /* ---- ML-KEM-768: structured JSON ---- */
+    {
+        role_table_t table;
+        role_entry_t kem_role;
+        static mnemonic_state_t mnemonic_state;
+        dispatcher_ctx_t dispatcher;
+        char *resp = NULL;
+        char *result_str = NULL;
+        cJSON *result_obj = NULL;
+        cJSON *alg_item = NULL;
+        cJSON *pk_item = NULL;
+        cJSON *kid_item = NULL;
+        const crypto_alg_sizes_t *sz;
+        int pr;
+
+        role_table_init(&table);
+        kem_role = make_entry("kem_main", "pq-kem", "ml-kem-768", 0);
+        role_table_add(&table, &kem_role);
+
+        mnemonic_init(&mnemonic_state);
+        mnemonic_load(&mnemonic_state, mnemonic);
+
+        memset(&g_key_store, 0, sizeof(g_key_store));
+        alg_key_cache_init(&g_alg_key_cache);
+        crypto_derive_all(&g_key_store, &table, &mnemonic_state);
+        dispatcher_init(&dispatcher, &table, &mnemonic_state, &g_key_store, &g_alg_key_cache);
+
+        sz = crypto_alg_get_sizes(CRYPTO_ALG_ML_KEM_768);
+        check_condition("ML-KEM-768 sizes available", sz != NULL);
+
+        resp = dispatcher_handle_request(&dispatcher,
+                                          "{\"id\":\"5\",\"method\":\"get_public_key\",\"params\":[{\"role\":\"kem_main\"}]}");
+        check_condition("ML-KEM-768 get_public_key returns a response", resp != NULL);
+
+        pr = parse_result(resp, &result_str, &result_obj);
+        check_condition("ML-KEM-768 get_public_key result is a JSON object",
+                        pr == 2 && result_obj != NULL);
+
+        if (result_obj != NULL && sz != NULL) {
+            alg_item = cJSON_GetObjectItemCaseSensitive(result_obj, "algorithm");
+            pk_item = cJSON_GetObjectItemCaseSensitive(result_obj, "public_key");
+            kid_item = cJSON_GetObjectItemCaseSensitive(result_obj, "key_id");
+            check_condition("ML-KEM-768 structured has algorithm=ml-kem-768",
+                            cJSON_IsString(alg_item) && strcmp(alg_item->valuestring, "ml-kem-768") == 0);
+            check_condition("ML-KEM-768 structured has public_key (2368 hex chars)",
+                            cJSON_IsString(pk_item) && strlen(pk_item->valuestring) == sz->pub_key_len * 2);
+            check_condition("ML-KEM-768 structured has key_id (16 hex chars)",
+                            cJSON_IsString(kid_item) && strlen(kid_item->valuestring) == 16);
+            check_condition("ML-KEM-768 key_id == first 16 chars of public_key",
+                            cJSON_IsString(pk_item) && cJSON_IsString(kid_item) &&
+                            strncmp(pk_item->valuestring, kid_item->valuestring, 16) == 0);
+        } else {
+            check_condition("ML-KEM-768 structured has algorithm=ml-kem-768", 0);
+            check_condition("ML-KEM-768 structured has public_key (2368 hex chars)", 0);
+            check_condition("ML-KEM-768 structured has key_id (16 hex chars)", 0);
+            check_condition("ML-KEM-768 key_id == first 16 chars of public_key", 0);
+        }
+
+        free(result_str);
+        cJSON_Delete(result_obj);
+        free(resp);
+        crypto_wipe(&g_key_store);
+        mnemonic_unload(&mnemonic_state);
+    }
+
+    printf("%d/%d tests passed\n", g_passes, g_total);
+    return (g_passes == g_total) ? 0 : 1;
+}

tests/test_role_table.c

@@ -82,6 +82,8 @@ typedef enum {
     PURPOSE_SSH,
     PURPOSE_AGE,
     PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,      /* post-quantum signatures (ML-DSA, SLH-DSA) */
+    PURPOSE_PQ_KEM,      /* post-quantum key encapsulation (ML-KEM) */
     PURPOSE_UNKNOWN
 } role_purpose_t;
 
@@ -90,6 +92,9 @@ typedef enum {
     CURVE_SECP256K1 = 0,
     CURVE_ED25519,
     CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
     CURVE_UNKNOWN
 } role_curve_t;
 
@@ -198,6 +203,24 @@ const char *selector_strerror(int err);
 #define ENFORCE_ERR_PURPOSE      -1 /* purpose mismatch */
 #define ENFORCE_ERR_CURVE        -2 /* curve mismatch */
 #define ENFORCE_ERR_UNKNOWN_VERB -3 /* verb not recognized */
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
 
 /* Known verbs */
 #define VERB_SIGN_EVENT     "sign_event"
@@ -233,6 +256,8 @@ const char *enforce_strerror(int err);
 #define POLICY_MAX_PURPOSES   8
 #define POLICY_VERB_MAX_LEN   32
 #define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
 
 /* Prompt behavior */
 typedef enum {
@@ -257,6 +282,12 @@ typedef struct {
     int role_count;
     char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
     int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
     prompt_mode_t prompt;
     policy_source_t source;
 } policy_entry_t;
@@ -290,6 +321,20 @@ int policy_check(const policy_table_t *table, const char *caller_id,
                  const char *verb, const char *role_name, const char *purpose,
                  policy_source_t *out_source);
 
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
 /* Parse prompt mode from string */
 prompt_mode_t prompt_mode_from_str(const char *s);
 
@@ -297,15 +342,147 @@ prompt_mode_t prompt_mode_from_str(const char *s);
 const char *prompt_mode_to_str(prompt_mode_t m);
 
 
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,   /* existing, Nostr */
+    CRYPTO_ALG_ED25519,         /* new, SSH signatures */
+    CRYPTO_ALG_X25519,          /* new, key agreement */
+    CRYPTO_ALG_ML_DSA_65,       /* new, PQ signatures */
+    CRYPTO_ALG_SLH_DSA_128S,    /* new, PQ signatures */
+    CRYPTO_ALG_ML_KEM_768,      /* new, PQ KEM */
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;           /* 0 for KEM */
+    size_t ciphertext_len;    /* 0 for signatures */
+    size_t shared_secret_len; /* 0 for signatures */
+} crypto_alg_sizes_t;
+
+/* Get size info for an algorithm. Returns NULL for CRYPTO_ALG_UNKNOWN. */
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+
+/* Map role_curve_t + role_purpose_t to crypto_alg_t.
+ * Returns CRYPTO_ALG_UNKNOWN for unsupported combinations. */
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+
+/* Convert crypto_alg_t to string. Returns NULL for unknown. */
+const char *crypto_alg_to_str(crypto_alg_t alg);
+
+/* Parse string to crypto_alg_t. Returns CRYPTO_ALG_UNKNOWN for unrecognized. */
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+
+
 /* from crypto.h */
 
 
 /* Per-role derived key material (stored in secure memory) */
 typedef struct {
-    secure_buf_t private_key;  /* 32 bytes, mlock'd */
-    unsigned char public_key[32];
-    char pubkey_hex[65];       /* 64 hex chars + null */
-    char npub[128];            /* bech32 npub */
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
     int valid;
 } derived_key_t;
 
@@ -336,6 +513,82 @@ char *crypto_sign_event(const key_store_t *store, int role_index, const char *ev
 void crypto_wipe(key_store_t *store);
 
 
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
 /* from dispatcher.h */
 
 
@@ -344,10 +597,11 @@ typedef struct {
     role_table_t *role_table;
     mnemonic_state_t *mnemonic;
     key_store_t *key_store;
+    algorithm_key_cache_t *alg_key_cache;  /* algorithm-based on-demand keys */
 } dispatcher_ctx_t;
 
 /* Initialize dispatcher context */
-void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store);
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
 
 /*
  * Process a JSON-RPC request string and produce a JSON-RPC response string.

tests/test_selector.c

@@ -82,6 +82,8 @@ typedef enum {
     PURPOSE_SSH,
     PURPOSE_AGE,
     PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,      /* post-quantum signatures (ML-DSA, SLH-DSA) */
+    PURPOSE_PQ_KEM,      /* post-quantum key encapsulation (ML-KEM) */
     PURPOSE_UNKNOWN
 } role_purpose_t;
 
@@ -90,6 +92,9 @@ typedef enum {
     CURVE_SECP256K1 = 0,
     CURVE_ED25519,
     CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
     CURVE_UNKNOWN
 } role_curve_t;
 
@@ -195,6 +200,24 @@ const char *selector_strerror(int err);
 #define ENFORCE_ERR_PURPOSE      -1 /* purpose mismatch */
 #define ENFORCE_ERR_CURVE        -2 /* curve mismatch */
 #define ENFORCE_ERR_UNKNOWN_VERB -3 /* verb not recognized */
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
 
 /* Known verbs */
 #define VERB_SIGN_EVENT     "sign_event"
@@ -230,6 +253,8 @@ const char *enforce_strerror(int err);
 #define POLICY_MAX_PURPOSES   8
 #define POLICY_VERB_MAX_LEN   32
 #define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
 
 /* Prompt behavior */
 typedef enum {
@@ -254,6 +279,12 @@ typedef struct {
     int role_count;
     char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
     int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
     prompt_mode_t prompt;
     policy_source_t source;
 } policy_entry_t;
@@ -287,6 +318,20 @@ int policy_check(const policy_table_t *table, const char *caller_id,
                  const char *verb, const char *role_name, const char *purpose,
                  policy_source_t *out_source);
 
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
 /* Parse prompt mode from string */
 prompt_mode_t prompt_mode_from_str(const char *s);
 
@@ -294,15 +339,147 @@ prompt_mode_t prompt_mode_from_str(const char *s);
 const char *prompt_mode_to_str(prompt_mode_t m);
 
 
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,   /* existing, Nostr */
+    CRYPTO_ALG_ED25519,         /* new, SSH signatures */
+    CRYPTO_ALG_X25519,          /* new, key agreement */
+    CRYPTO_ALG_ML_DSA_65,       /* new, PQ signatures */
+    CRYPTO_ALG_SLH_DSA_128S,    /* new, PQ signatures */
+    CRYPTO_ALG_ML_KEM_768,      /* new, PQ KEM */
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;           /* 0 for KEM */
+    size_t ciphertext_len;    /* 0 for signatures */
+    size_t shared_secret_len; /* 0 for signatures */
+} crypto_alg_sizes_t;
+
+/* Get size info for an algorithm. Returns NULL for CRYPTO_ALG_UNKNOWN. */
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+
+/* Map role_curve_t + role_purpose_t to crypto_alg_t.
+ * Returns CRYPTO_ALG_UNKNOWN for unsupported combinations. */
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+
+/* Convert crypto_alg_t to string. Returns NULL for unknown. */
+const char *crypto_alg_to_str(crypto_alg_t alg);
+
+/* Parse string to crypto_alg_t. Returns CRYPTO_ALG_UNKNOWN for unrecognized. */
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+
+
 /* from crypto.h */
 
 
 /* Per-role derived key material (stored in secure memory) */
 typedef struct {
-    secure_buf_t private_key;  /* 32 bytes, mlock'd */
-    unsigned char public_key[32];
-    char pubkey_hex[65];       /* 64 hex chars + null */
-    char npub[128];            /* bech32 npub */
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
     int valid;
 } derived_key_t;
 
@@ -333,6 +510,82 @@ char *crypto_sign_event(const key_store_t *store, int role_index, const char *ev
 void crypto_wipe(key_store_t *store);
 
 
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
 /* from dispatcher.h */
 
 
@@ -341,10 +594,11 @@ typedef struct {
     role_table_t *role_table;
     mnemonic_state_t *mnemonic;
     key_store_t *key_store;
+    algorithm_key_cache_t *alg_key_cache;  /* algorithm-based on-demand keys */
 } dispatcher_ctx_t;
 
 /* Initialize dispatcher context */
-void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store);
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
 
 /*
  * Process a JSON-RPC request string and produce a JSON-RPC response string.

tests/test_slh_dsa_128s.c

@@ -0,0 +1,837 @@
+/* Test for Phase 4 SLH-DSA-128s (FIPS 205) post-quantum hash-based signatures.
+ *
+ * Verifies:
+ *   - SLH-DSA-128s keygen from seed: 32-byte pub, 64-byte priv
+ *   - SLH-DSA-128s keygen determinism: same seed -> same keypair
+ *   - SLH-DSA-128s sign/verify roundtrip: sign a message, verify passes
+ *   - SLH-DSA-128s sign/verify with wrong message: verify fails
+ *   - SLH-DSA-128s sign/verify with wrong key: verify fails
+ *   - DRBG determinism: same seed -> same randombytes output
+ *   - Integration: derive SLH-DSA-128s key from mnemonic via crypto_derive_one,
+ *     sign data via sign_data verb through dispatcher, verify signature
+ *   - Enforcement: sign_data allowed on pq-sig+slh-dsa-128s
+ */
+/* NSIGNER_HEADERLESS_DECLS_BEGIN */
+#include <stddef.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <cJSON.h>
+
+/* from secure_mem.h */
+
+
+typedef struct {
+    void *data;
+    size_t size;
+    int locked;
+} secure_buf_t;
+
+int secure_buf_alloc(secure_buf_t *buf, size_t size);
+void secure_buf_free(secure_buf_t *buf);
+void secure_memzero(void *ptr, size_t len);
+
+
+/* from mnemonic.h */
+
+
+#define MNEMONIC_MAX_LEN 256
+
+typedef struct {
+    secure_buf_t buf;
+    int loaded;
+    int word_count;
+} mnemonic_state_t;
+
+void mnemonic_init(mnemonic_state_t *state);
+int mnemonic_load(mnemonic_state_t *state, const char *phrase);
+void mnemonic_unload(mnemonic_state_t *state);
+int mnemonic_is_loaded(const mnemonic_state_t *state);
+const char *mnemonic_get_phrase(const mnemonic_state_t *state);
+int mnemonic_generate(int word_count, char *out, size_t out_len);
+
+
+/* from role_table.h */
+
+
+#define ROLE_NAME_MAX 64
+#define ROLE_PATH_MAX 128
+#define ROLE_PURPOSE_MAX 32
+#define ROLE_CURVE_MAX 16
+#define ROLE_PUBKEY_HEX_MAX 66
+#define ROLE_TABLE_MAX_ENTRIES 256
+
+typedef enum {
+    PURPOSE_NOSTR = 0,
+    PURPOSE_BITCOIN,
+    PURPOSE_SSH,
+    PURPOSE_AGE,
+    PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,
+    PURPOSE_PQ_KEM,
+    PURPOSE_UNKNOWN
+} role_purpose_t;
+
+typedef enum {
+    CURVE_SECP256K1 = 0,
+    CURVE_ED25519,
+    CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
+    CURVE_UNKNOWN
+} role_curve_t;
+
+typedef enum {
+    SELECTOR_NOSTR_INDEX,
+    SELECTOR_ROLE_PATH
+} role_selector_type_t;
+
+typedef struct {
+    char name[ROLE_NAME_MAX];
+    char purpose_str[ROLE_PURPOSE_MAX];
+    char curve_str[ROLE_CURVE_MAX];
+    role_purpose_t purpose;
+    role_curve_t curve;
+    role_selector_type_t selector_type;
+    int nostr_index;
+    char role_path[ROLE_PATH_MAX];
+    char pubkey_hex[ROLE_PUBKEY_HEX_MAX];
+    int derived;
+} role_entry_t;
+
+typedef struct {
+    role_entry_t entries[ROLE_TABLE_MAX_ENTRIES];
+    int count;
+} role_table_t;
+
+void role_table_init(role_table_t *table);
+int role_table_add(role_table_t *table, const role_entry_t *entry);
+role_entry_t *role_table_find_by_name(role_table_t *table, const char *name);
+role_purpose_t role_purpose_from_str(const char *s);
+role_curve_t role_curve_from_str(const char *s);
+const char *role_purpose_to_str(role_purpose_t p);
+const char *role_curve_to_str(role_curve_t c);
+
+
+/* from selector.h */
+
+
+#define SELECTOR_OK                 0
+#define SELECTOR_ERR_AMBIGUOUS     -1
+#define SELECTOR_ERR_NOT_FOUND     -2
+#define SELECTOR_ERR_NO_DEFAULT    -3
+
+typedef struct {
+    int has_role;
+    char role_name[ROLE_NAME_MAX];
+    int has_nostr_index;
+    int nostr_index;
+    int has_role_path;
+    char role_path[ROLE_PATH_MAX];
+} selector_request_t;
+
+void selector_request_init(selector_request_t *req);
+int selector_resolve(const selector_request_t *req, role_table_t *table, role_entry_t **out);
+const char *selector_strerror(int err);
+
+
+/* from enforcement.h */
+
+
+#define ENFORCE_OK                0
+#define ENFORCE_ERR_PURPOSE      -1
+#define ENFORCE_ERR_CURVE        -2
+#define ENFORCE_ERR_UNKNOWN_VERB -3
+
+#define VERB_SIGN_EVENT     "sign_event"
+#define VERB_GET_PUBLIC_KEY "get_public_key"
+#define VERB_NIP44_ENCRYPT  "nip44_encrypt"
+#define VERB_NIP44_DECRYPT  "nip44_decrypt"
+#define VERB_NIP04_ENCRYPT  "nip04_encrypt"
+#define VERB_NIP04_DECRYPT  "nip04_decrypt"
+#define VERB_MINE_EVENT     "mine_event"
+#define VERB_SIGN_DATA      "sign_data"
+#define VERB_VERIFY_SIG     "verify_signature"
+#define VERB_SSH_SIGN       "ssh_sign"
+#define VERB_KEM_ENCAPS     "kem_encapsulate"
+#define VERB_KEM_DECAPS     "kem_decapsulate"
+
+int enforce_verb_role(const char *verb, const role_entry_t *role);
+const char *enforce_strerror(int err);
+
+
+/* from policy.h */
+
+
+#define POLICY_MAX_ENTRIES    32
+#define POLICY_MAX_VERBS      16
+#define POLICY_MAX_ROLES      16
+#define POLICY_MAX_PURPOSES   8
+#define POLICY_VERB_MAX_LEN   32
+#define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
+
+typedef enum {
+    PROMPT_NEVER = 0,
+    PROMPT_FIRST_PER_BOOT,
+    PROMPT_EVERY_REQUEST,
+    PROMPT_DENY
+} prompt_mode_t;
+
+typedef enum {
+    POLICY_SOURCE_DEFAULT = 0,
+    POLICY_SOURCE_PREAPPROVE,
+    POLICY_SOURCE_SESSION_GRANT
+} policy_source_t;
+
+typedef struct {
+    char caller[POLICY_CALLER_MAX_LEN];
+    char verbs[POLICY_MAX_VERBS][POLICY_VERB_MAX_LEN];
+    int verb_count;
+    char roles[POLICY_MAX_ROLES][ROLE_NAME_MAX];
+    int role_count;
+    char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
+    int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
+    prompt_mode_t prompt;
+    policy_source_t source;
+} policy_entry_t;
+
+typedef struct {
+    policy_entry_t entries[POLICY_MAX_ENTRIES];
+    int count;
+} policy_table_t;
+
+#define POLICY_ALLOW     0
+#define POLICY_DENY     -1
+#define POLICY_PROMPT   -2
+#define POLICY_NO_MATCH -3
+
+void policy_table_init(policy_table_t *table);
+void policy_init_default(policy_table_t *table, uid_t owner_uid);
+int policy_table_add(policy_table_t *table, const policy_entry_t *entry);
+int policy_check(const policy_table_t *table, const char *caller_id,
+                 const char *verb, const char *role_name, const char *purpose,
+                 policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+prompt_mode_t prompt_mode_from_str(const char *s);
+const char *prompt_mode_to_str(prompt_mode_t m);
+
+
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,
+    CRYPTO_ALG_ED25519,
+    CRYPTO_ALG_X25519,
+    CRYPTO_ALG_ML_DSA_65,
+    CRYPTO_ALG_SLH_DSA_128S,
+    CRYPTO_ALG_ML_KEM_768,
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;
+    size_t ciphertext_len;
+    size_t shared_secret_len;
+} crypto_alg_sizes_t;
+
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+const char *crypto_alg_to_str(crypto_alg_t alg);
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                      unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                          const unsigned char *msg, size_t msg_len,
+                          unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                            const unsigned char *msg, size_t msg_len,
+                            const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                         const unsigned char *peer_pub, size_t pub_len,
+                         unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                       unsigned char *seed_out, size_t seed_out_len);
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                        unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                            const unsigned char *msg, size_t msg_len,
+                            unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                              const unsigned char *msg, size_t msg_len,
+                              const unsigned char *sig, size_t sig_len);
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+/* from crypto.h */
+
+
+/* Per-role derived key material (stored in secure memory) */
+typedef struct {
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
+    int valid;
+} derived_key_t;
+
+typedef struct {
+    derived_key_t keys[ROLE_TABLE_MAX_ENTRIES];
+    int count;
+} key_store_t;
+
+int crypto_derive_all(key_store_t *store, role_table_t *table, const mnemonic_state_t *mnemonic);
+int crypto_derive_one(key_store_t *store, role_table_t *table, const mnemonic_state_t *mnemonic, int role_index);
+const unsigned char *crypto_get_private_key(const key_store_t *store, int role_index);
+const char *crypto_get_pubkey_hex(const key_store_t *store, int role_index);
+char *crypto_sign_event(const key_store_t *store, int role_index, const char *event_json);
+void crypto_wipe(key_store_t *store);
+
+
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
+/* from dispatcher.h */
+
+
+typedef struct {
+    role_table_t *role_table;
+    mnemonic_state_t *mnemonic;
+    key_store_t *key_store;
+} dispatcher_ctx_t;
+
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
+char *dispatcher_handle_request(dispatcher_ctx_t *ctx, const char *json_request);
+
+
+/* NSIGNER_HEADERLESS_DECLS_END */
+
+static key_store_t g_key_store;
+
+static algorithm_key_cache_t g_alg_key_cache;
+
+#include <nostr_core/nostr_common.h>
+#include <nostr_core/utils.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* SLH-DSA-128s key sizes (FIPS 205) */
+#define SLH_DSA_128S_PUBKEY_BYTES  32
+#define SLH_DSA_128S_PRIVKEY_BYTES 64
+#define SLH_DSA_128S_SIG_BYTES     7856
+
+static int g_passes = 0;
+static int g_total = 0;
+
+static void check_condition(const char *name, int condition) {
+    g_total++;
+    if (condition) {
+        printf("PASS: %s\n", name);
+        g_passes++;
+    } else {
+        printf("FAIL: %s\n", name);
+    }
+}
+
+static int response_has(const char *response, const char *needle) {
+    return (response != NULL && needle != NULL && strstr(response, needle) != NULL);
+}
+
+static role_entry_t make_pq_sig_slh_dsa_128s_entry(const char *name, int idx) {
+    role_entry_t e;
+    memset(&e, 0, sizeof(e));
+    strncpy(e.name, name, sizeof(e.name) - 1);
+    strncpy(e.purpose_str, "pq-sig", sizeof(e.purpose_str) - 1);
+    strncpy(e.curve_str, "slh-dsa-128s", sizeof(e.curve_str) - 1);
+    e.purpose = role_purpose_from_str(e.purpose_str);
+    e.curve = role_curve_from_str(e.curve_str);
+    e.selector_type = SELECTOR_NOSTR_INDEX;
+    e.nostr_index = idx;
+    e.derived = 0;
+    return e;
+}
+
+static role_entry_t make_nostr_secp_entry(const char *name, int idx) {
+    role_entry_t e;
+    memset(&e, 0, sizeof(e));
+    strncpy(e.name, name, sizeof(e.name) - 1);
+    strncpy(e.purpose_str, "nostr", sizeof(e.purpose_str) - 1);
+    strncpy(e.curve_str, "secp256k1", sizeof(e.curve_str) - 1);
+    e.purpose = role_purpose_from_str(e.purpose_str);
+    e.curve = role_curve_from_str(e.curve_str);
+    e.selector_type = SELECTOR_NOSTR_INDEX;
+    e.nostr_index = idx;
+    e.derived = 0;
+    return e;
+}
+
+int main(void) {
+    /* Test mnemonic (BIP-39 standard test vector). */
+    const char *mnemonic = "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about";
+    unsigned char seed[32];
+    unsigned char *priv1, *pub1, *priv2, *pub2;
+    unsigned char *sig;
+    size_t sig_len;
+    int rc;
+
+    /* Allocate key buffers on the heap */
+    priv1 = (unsigned char *)malloc(SLH_DSA_128S_PRIVKEY_BYTES);
+    pub1 = (unsigned char *)malloc(SLH_DSA_128S_PUBKEY_BYTES);
+    priv2 = (unsigned char *)malloc(SLH_DSA_128S_PRIVKEY_BYTES);
+    pub2 = (unsigned char *)malloc(SLH_DSA_128S_PUBKEY_BYTES);
+    sig = (unsigned char *)malloc(SLH_DSA_128S_SIG_BYTES);
+
+    if (!priv1 || !pub1 || !priv2 || !pub2 || !sig) {
+        printf("FAIL: memory allocation\n");
+        return 1;
+    }
+
+    /* ---- DRBG determinism ---- */
+    {
+        unsigned char out1[64], out2[64];
+
+        memset(seed, 0x42, 32);
+        pq_drbg_init(seed, 32);
+        rc = pq_drbg_randombytes(out1, 64);
+        check_condition("DRBG randombytes succeeds", rc == 0);
+
+        pq_drbg_zeroize();
+
+        memset(seed, 0x42, 32);
+        pq_drbg_init(seed, 32);
+        rc = pq_drbg_randombytes(out2, 64);
+        check_condition("DRBG randombytes succeeds (2nd)", rc == 0);
+
+        check_condition("DRBG determinism (same seed -> same output)",
+                        memcmp(out1, out2, 64) == 0);
+
+        pq_drbg_zeroize();
+    }
+
+    /* ---- SLH-DSA-128s keygen from seed ---- */
+    memset(seed, 0x42, 32);
+    rc = crypto_slh_dsa_128s_keygen_from_seed(seed, 32, priv1, pub1);
+    check_condition("SLH-DSA-128s keygen from seed succeeds", rc == 0);
+
+    /* Keygen determinism: same seed -> same keypair */
+    memset(seed, 0x42, 32);
+    rc = crypto_slh_dsa_128s_keygen_from_seed(seed, 32, priv2, pub2);
+    check_condition("SLH-DSA-128s keygen determinism (same seed -> same key)", rc == 0 &&
+                    memcmp(priv1, priv2, SLH_DSA_128S_PRIVKEY_BYTES) == 0 &&
+                    memcmp(pub1, pub2, SLH_DSA_128S_PUBKEY_BYTES) == 0);
+
+    /* Different seed -> different keypair */
+    memset(seed, 0x99, 32);
+    rc = crypto_slh_dsa_128s_keygen_from_seed(seed, 32, priv2, pub2);
+    check_condition("SLH-DSA-128s keygen different seed -> different key", rc == 0 &&
+                    memcmp(pub1, pub2, SLH_DSA_128S_PUBKEY_BYTES) != 0);
+
+    /* ---- SLH-DSA-128s sign/verify roundtrip ---- */
+    memset(seed, 0x42, 32);
+    crypto_slh_dsa_128s_keygen_from_seed(seed, 32, priv1, pub1);
+    {
+        const char *msg = "hello world";
+        sig_len = SLH_DSA_128S_SIG_BYTES;
+        rc = crypto_slh_dsa_128s_sign(priv1, SLH_DSA_128S_PRIVKEY_BYTES,
+                                        (const unsigned char *)msg, strlen(msg),
+                                        sig, &sig_len);
+        check_condition("SLH-DSA-128s sign succeeds", rc == 0 && sig_len > 0);
+        check_condition("SLH-DSA-128s signature is 7856 bytes", sig_len == SLH_DSA_128S_SIG_BYTES);
+
+        rc = crypto_slh_dsa_128s_verify(pub1, SLH_DSA_128S_PUBKEY_BYTES,
+                                          (const unsigned char *)msg, strlen(msg),
+                                          sig, sig_len);
+        check_condition("SLH-DSA-128s verify valid signature", rc == 0);
+
+        /* Wrong message should fail */
+        {
+            const char *wrong_msg = "hello worle";
+            rc = crypto_slh_dsa_128s_verify(pub1, SLH_DSA_128S_PUBKEY_BYTES,
+                                              (const unsigned char *)wrong_msg, strlen(wrong_msg),
+                                              sig, sig_len);
+            check_condition("SLH-DSA-128s verify wrong message -> invalid", rc == 1);
+        }
+
+        /* Wrong key should fail */
+        memset(seed, 0xAB, 32);
+        crypto_slh_dsa_128s_keygen_from_seed(seed, 32, priv2, pub2);
+        rc = crypto_slh_dsa_128s_verify(pub2, SLH_DSA_128S_PUBKEY_BYTES,
+                                          (const unsigned char *)msg, strlen(msg),
+                                          sig, sig_len);
+        check_condition("SLH-DSA-128s verify wrong key -> invalid", rc == 1);
+    }
+
+    /* ---- Integration: derive SLH-DSA-128s key via crypto_derive_all ---- */
+    {
+        role_table_t table;
+        role_entry_t pq_role;
+        static mnemonic_state_t mnemonic_state;
+            int derived;
+
+        role_table_init(&table);
+        pq_role = make_pq_sig_slh_dsa_128s_entry("pq_main", 0);
+        role_table_add(&table, &pq_role);
+
+        mnemonic_init(&mnemonic_state);
+        mnemonic_load(&mnemonic_state, mnemonic);
+
+        memset(&g_key_store, 0, sizeof(g_key_store));
+        alg_key_cache_init(&g_alg_key_cache);
+        derived = crypto_derive_all(&g_key_store, &table, &mnemonic_state);
+        check_condition("crypto_derive_all derives SLH-DSA-128s key", derived == 1);
+
+        {
+            const char *pub_hex = crypto_get_pubkey_hex(&g_key_store, 0);
+            /* 32 bytes hex-encoded = 64 hex chars + null */
+            check_condition("SLH-DSA-128s derived pubkey hex is 64 chars",
+                            pub_hex != NULL && strlen(pub_hex) == 64);
+        }
+
+        {
+            const unsigned char *priv = crypto_get_private_key(&g_key_store, 0);
+            check_condition("SLH-DSA-128s derived private key not NULL", priv != NULL);
+        }
+
+        /* Determinism: re-derive and check same key */
+        {
+            static key_store_t key_store2;
+            memset(&key_store2, 0, sizeof(key_store2));
+            crypto_derive_all(&key_store2, &table, &mnemonic_state);
+            {
+                const char *pub_hex1 = crypto_get_pubkey_hex(&g_key_store, 0);
+                const char *pub_hex2 = crypto_get_pubkey_hex(&key_store2, 0);
+                check_condition("SLH-DSA-128s derivation determinism (same mnemonic -> same key)",
+                                pub_hex1 != NULL && pub_hex2 != NULL &&
+                                strcmp(pub_hex1, pub_hex2) == 0);
+            }
+            crypto_wipe(&key_store2);
+        }
+
+        crypto_wipe(&g_key_store);
+        mnemonic_unload(&mnemonic_state);
+    }
+
+    /* ---- Integration: sign_data via dispatcher ---- */
+    {
+        role_table_t table;
+        role_entry_t pq_role;
+        static mnemonic_state_t mnemonic_state;
+        dispatcher_ctx_t dispatcher;
+        char *resp;
+        const char *msg_hex = "68656c6c6f20776f726c64"; /* "hello world" in hex */
+        char request[512];
+
+        role_table_init(&table);
+        pq_role = make_pq_sig_slh_dsa_128s_entry("pq_main", 0);
+        role_table_add(&table, &pq_role);
+
+        mnemonic_init(&mnemonic_state);
+        mnemonic_load(&mnemonic_state, mnemonic);
+
+        memset(&g_key_store, 0, sizeof(g_key_store));
+        alg_key_cache_init(&g_alg_key_cache);
+        crypto_derive_all(&g_key_store, &table, &mnemonic_state);
+
+        dispatcher_init(&dispatcher, &table, &mnemonic_state, &g_key_store, &g_alg_key_cache);
+
+        /* sign_data request */
+        snprintf(request, sizeof(request),
+                 "{\"id\":\"test1\",\"method\":\"sign_data\",\"params\":[\"%s\",{\"role\":\"pq_main\"}]}",
+                 msg_hex);
+        resp = dispatcher_handle_request(&dispatcher, request);
+        check_condition("sign_data via dispatcher returns result",
+                        resp != NULL && response_has(resp, "\"result\""));
+        check_condition("sign_data result contains signature",
+                        resp != NULL && response_has(resp, "signature"));
+        check_condition("sign_data result contains algorithm slh-dsa-128s",
+                        resp != NULL && response_has(resp, "slh-dsa-128s"));
+        free(resp);
+
+        crypto_wipe(&g_key_store);
+        mnemonic_unload(&mnemonic_state);
+    }
+
+    /* ---- Integration: verify_signature roundtrip via dispatcher ---- */
+    {
+        role_table_t table;
+        role_entry_t pq_role;
+        static mnemonic_state_t mnemonic_state;
+        dispatcher_ctx_t dispatcher;
+        char *sign_resp, *verify_resp;
+        const char *msg_hex = "68656c6c6f20776f726c64"; /* "hello world" */
+        char sign_req[512];
+        /* SLH-DSA-128s sig is 7856 bytes = 15712 hex chars. The verify request
+         * needs: JSON overhead + msg_hex (22) + sig_hex (15712) + options ~50
+         * = ~16000 bytes. Use 20000 to be safe. */
+        char *verify_req = (char *)malloc(20000);
+        cJSON *sign_json, *result_item, *sig_item;
+        const char *sig_str = NULL;
+
+        role_table_init(&table);
+        pq_role = make_pq_sig_slh_dsa_128s_entry("pq_main", 0);
+        role_table_add(&table, &pq_role);
+
+        mnemonic_init(&mnemonic_state);
+        mnemonic_load(&mnemonic_state, mnemonic);
+
+        memset(&g_key_store, 0, sizeof(g_key_store));
+        alg_key_cache_init(&g_alg_key_cache);
+        crypto_derive_all(&g_key_store, &table, &mnemonic_state);
+        dispatcher_init(&dispatcher, &table, &mnemonic_state, &g_key_store, &g_alg_key_cache);
+
+        /* Sign */
+        snprintf(sign_req, sizeof(sign_req),
+                 "{\"id\":\"s1\",\"method\":\"sign_data\",\"params\":[\"%s\",{\"role\":\"pq_main\"}]}",
+                 msg_hex);
+        sign_resp = dispatcher_handle_request(&dispatcher, sign_req);
+        check_condition("verify roundtrip: sign_data succeeds", sign_resp != NULL);
+
+        /* Extract signature from result */
+        if (sign_resp != NULL) {
+            sign_json = cJSON_Parse(sign_resp);
+            if (sign_json != NULL) {
+                result_item = cJSON_GetObjectItemCaseSensitive(sign_json, "result");
+                if (cJSON_IsString(result_item)) {
+                    cJSON *result_obj = cJSON_Parse(result_item->valuestring);
+                    if (result_obj != NULL) {
+                        sig_item = cJSON_GetObjectItemCaseSensitive(result_obj, "signature");
+                        if (cJSON_IsString(sig_item)) {
+                            sig_str = strdup(sig_item->valuestring);
+                        }
+                        cJSON_Delete(result_obj);
+                    }
+                }
+                cJSON_Delete(sign_json);
+            }
+        }
+        check_condition("verify roundtrip: extracted signature hex", sig_str != NULL);
+
+        /* Verify */
+        if (sig_str != NULL && verify_req != NULL) {
+            snprintf(verify_req, 20000,
+                     "{\"id\":\"v1\",\"method\":\"verify_signature\",\"params\":[\"%s\",\"%s\",{\"role\":\"pq_main\"}]}",
+                     msg_hex, sig_str);
+            verify_resp = dispatcher_handle_request(&dispatcher, verify_req);
+            check_condition("verify_signature returns valid:true",
+                            verify_resp != NULL && response_has(verify_resp, "valid") &&
+                            response_has(verify_resp, "true"));
+            free(verify_resp);
+
+            /* Verify with wrong message */
+            snprintf(verify_req, 20000,
+                     "{\"id\":\"v2\",\"method\":\"verify_signature\",\"params\":[\"00ff\",\"%s\",{\"role\":\"pq_main\"}]}",
+                     sig_str);
+            verify_resp = dispatcher_handle_request(&dispatcher, verify_req);
+            check_condition("verify_signature wrong msg returns valid:false",
+                            verify_resp != NULL && response_has(verify_resp, "valid") &&
+                            response_has(verify_resp, "false"));
+            free(verify_resp);
+
+            free((void *)sig_str);
+        } else {
+            check_condition("verify_signature returns valid:true", 0);
+            check_condition("verify_signature wrong msg returns valid:false", 0);
+        }
+
+        free(verify_req);
+        free(sign_resp);
+        crypto_wipe(&g_key_store);
+        mnemonic_unload(&mnemonic_state);
+    }
+
+    /* ---- Enforcement: sign_data on pq-sig+slh-dsa-128s ---- */
+    {
+        role_entry_t pq_sig = make_pq_sig_slh_dsa_128s_entry("pq", 0);
+        role_entry_t nostr_secp = make_nostr_secp_entry("nostr", 0);
+
+        check_condition("enforce sign_data + pq-sig/slh-dsa-128s -> OK",
+                        enforce_verb_role(VERB_SIGN_DATA, &pq_sig) == ENFORCE_OK);
+
+        check_condition("enforce sign_data + nostr/secp256k1 -> PURPOSE err",
+                        enforce_verb_role(VERB_SIGN_DATA, &nostr_secp) == ENFORCE_ERR_PURPOSE);
+
+        check_condition("enforce verify_signature + pq-sig/slh-dsa-128s -> OK",
+                        enforce_verb_role(VERB_VERIFY_SIG, &pq_sig) == ENFORCE_OK);
+    }
+
+    /* ---- Cleanup ---- */
+    free(priv1);
+    free(pub1);
+    free(priv2);
+    free(pub2);
+    free(sig);
+
+    printf("\n%d/%d tests passed\n", g_passes, g_total);
+    return (g_passes == g_total) ? 0 : 1;
+}

tests/test_socket_name.c

@@ -82,6 +82,8 @@ typedef enum {
     PURPOSE_SSH,
     PURPOSE_AGE,
     PURPOSE_FIPS,
+    PURPOSE_PQ_SIG,      /* post-quantum signatures (ML-DSA, SLH-DSA) */
+    PURPOSE_PQ_KEM,      /* post-quantum key encapsulation (ML-KEM) */
     PURPOSE_UNKNOWN
 } role_purpose_t;
 
@@ -90,6 +92,9 @@ typedef enum {
     CURVE_SECP256K1 = 0,
     CURVE_ED25519,
     CURVE_X25519,
+    CURVE_ML_DSA_65,
+    CURVE_SLH_DSA_128S,
+    CURVE_ML_KEM_768,
     CURVE_UNKNOWN
 } role_curve_t;
 
@@ -195,6 +200,24 @@ const char *selector_strerror(int err);
 #define ENFORCE_ERR_PURPOSE      -1 /* purpose mismatch */
 #define ENFORCE_ERR_CURVE        -2 /* curve mismatch */
 #define ENFORCE_ERR_UNKNOWN_VERB -3 /* verb not recognized */
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
+#define ENFORCE_ERR_ALGORITHM  -4 /* algorithm not valid for verb */
+
+/* New algorithm-based verb defines (algorithm is a parameter, not implicit) */
+#define VERB_SIGN              "sign"
+#define VERB_VERIFY            "verify"
+#define VERB_ENCAPSULATE       "encapsulate"
+#define VERB_DECAPSULATE       "decapsulate"
+#define VERB_DERIVE_SHARED     "derive_shared_secret"
+
 
 /* Known verbs */
 #define VERB_SIGN_EVENT     "sign_event"
@@ -230,6 +253,8 @@ const char *enforce_strerror(int err);
 #define POLICY_MAX_PURPOSES   8
 #define POLICY_VERB_MAX_LEN   32
 #define POLICY_CALLER_MAX_LEN 160
+#define POLICY_MAX_ALGS       16
+#define POLICY_MAX_ALGS       16
 
 /* Prompt behavior */
 typedef enum {
@@ -254,6 +279,12 @@ typedef struct {
     int role_count;
     char purposes[POLICY_MAX_PURPOSES][ROLE_PURPOSE_MAX];
     int purpose_count;
+    /* Algorithm-based (new) */
+    char algorithms[16][32];  /* algorithm names; POLICY_MAX_ALGS */
+    int alg_count;
+    int index_min;            /* -1 = any */
+    int index_max;            /* -1 = any */
+    /* Common */
     prompt_mode_t prompt;
     policy_source_t source;
 } policy_entry_t;
@@ -287,6 +318,20 @@ int policy_check(const policy_table_t *table, const char *caller_id,
                  const char *verb, const char *role_name, const char *purpose,
                  policy_source_t *out_source);
 
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
+/* Check whether caller_id is allowed to invoke `verb` with the given
+ * algorithm and index (algorithm-based policy). Returns POLICY_ALLOW,
+ * POLICY_DENY, POLICY_PROMPT, or POLICY_NO_MATCH. */
+int policy_check_algorithm(const policy_table_t *table, const char *caller_id,
+                           const char *verb, const char *algorithm, int index,
+                           policy_source_t *out_source);
+
 /* Parse prompt mode from string */
 prompt_mode_t prompt_mode_from_str(const char *s);
 
@@ -294,15 +339,147 @@ prompt_mode_t prompt_mode_from_str(const char *s);
 const char *prompt_mode_to_str(prompt_mode_t m);
 
 
+/* from pq_crypto.h */
+
+
+/* Algorithm identifiers */
+typedef enum {
+    CRYPTO_ALG_SECP256K1 = 0,   /* existing, Nostr */
+    CRYPTO_ALG_ED25519,         /* new, SSH signatures */
+    CRYPTO_ALG_X25519,          /* new, key agreement */
+    CRYPTO_ALG_ML_DSA_65,       /* new, PQ signatures */
+    CRYPTO_ALG_SLH_DSA_128S,    /* new, PQ signatures */
+    CRYPTO_ALG_ML_KEM_768,      /* new, PQ KEM */
+    CRYPTO_ALG_UNKNOWN
+} crypto_alg_t;
+
+/* Key sizes for each algorithm (compile-time constants) */
+typedef struct {
+    size_t priv_key_len;
+    size_t pub_key_len;
+    size_t sig_len;           /* 0 for KEM */
+    size_t ciphertext_len;    /* 0 for signatures */
+    size_t shared_secret_len; /* 0 for signatures */
+} crypto_alg_sizes_t;
+
+/* Get size info for an algorithm. Returns NULL for CRYPTO_ALG_UNKNOWN. */
+const crypto_alg_sizes_t *crypto_alg_get_sizes(crypto_alg_t alg);
+
+/* Map role_curve_t + role_purpose_t to crypto_alg_t.
+ * Returns CRYPTO_ALG_UNKNOWN for unsupported combinations. */
+crypto_alg_t crypto_alg_from_role(role_curve_t curve, role_purpose_t purpose);
+
+/* Convert crypto_alg_t to string. Returns NULL for unknown. */
+const char *crypto_alg_to_str(crypto_alg_t alg);
+
+/* Parse string to crypto_alg_t. Returns CRYPTO_ALG_UNKNOWN for unrecognized. */
+crypto_alg_t crypto_alg_from_str(const char *s);
+/* ed25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_ed25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                     unsigned char *priv_out, unsigned char *pub_out);
+
+/* ed25519: sign a message. priv is 32-byte private key.
+ * sig_out must be at least 64 bytes. Returns 0 on success, -1 on error. */
+int crypto_ed25519_sign(const unsigned char *priv, size_t priv_len,
+                         const unsigned char *msg, size_t msg_len,
+                         unsigned char *sig_out, size_t *sig_out_len);
+
+/* ed25519: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ed25519_verify(const unsigned char *pub, size_t pub_len,
+                           const unsigned char *msg, size_t msg_len,
+                           const unsigned char *sig, size_t sig_len);
+
+/* x25519: derive keypair from a 32-byte seed.
+ * priv_out and pub_out must be at least 32 bytes each.
+ * Returns 0 on success, -1 on error. */
+int crypto_x25519_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                    unsigned char *priv_out, unsigned char *pub_out);
+
+/* x25519: derive shared secret from our private key and peer's public key.
+ * shared_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_x25519_ecdh(const unsigned char *our_priv, size_t priv_len,
+                        const unsigned char *peer_pub, size_t pub_len,
+                        unsigned char *shared_out, size_t *shared_out_len);
+
+/* Derive a 32-byte seed from a mnemonic using a BIP-44 path (SLIP-0010).
+ * seed_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_derive_seed_from_mnemonic(const char *mnemonic, const char *path,
+                                      unsigned char *seed_out, size_t seed_out_len);
+/* ML-DSA-65: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 4032 bytes, pub_out at least 1952 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                       unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-DSA-65: sign a message. priv is 4032-byte private key.
+ * sig_out must be at least 3309 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_dsa_65_sign(const unsigned char *priv, size_t priv_len,
+                           const unsigned char *msg, size_t msg_len,
+                           unsigned char *sig_out, size_t *sig_out_len);
+
+/* ML-DSA-65: verify a signature. pub is 1952-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_ml_dsa_65_verify(const unsigned char *pub, size_t pub_len,
+                             const unsigned char *msg, size_t msg_len,
+                             const unsigned char *sig, size_t sig_len);
+
+
+/* SLH-DSA-128s: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 64 bytes, pub_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                           unsigned char *priv_out, unsigned char *pub_out);
+
+/* SLH-DSA-128s: sign a message. priv is 64-byte private key.
+ * sig_out must be at least 7856 bytes. Returns 0 on success, -1 on error. */
+int crypto_slh_dsa_128s_sign(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *msg, size_t msg_len,
+                               unsigned char *sig_out, size_t *sig_out_len);
+
+/* SLH-DSA-128s: verify a signature. pub is 32-byte public key.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_slh_dsa_128s_verify(const unsigned char *pub, size_t pub_len,
+                                 const unsigned char *msg, size_t msg_len,
+                                 const unsigned char *sig, size_t sig_len);
+
+/* ML-KEM-768: generate keypair from a 32-byte seed (deterministic).
+ * priv_out must be at least 2400 bytes, pub_out at least 1184 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_keygen_from_seed(const unsigned char *seed, size_t seed_len,
+                                         unsigned char *priv_out, unsigned char *pub_out);
+
+/* ML-KEM-768: encapsulate. pub is 1184-byte public key.
+ * ct_out must be at least 1088 bytes, ss_out at least 32 bytes.
+ * Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_encaps(const unsigned char *pub, size_t pub_len,
+                               unsigned char *ct_out, unsigned char *ss_out);
+
+/* ML-KEM-768: decapsulate. priv is 2400-byte secret key, ct is 1088-byte ciphertext.
+ * ss_out must be at least 32 bytes. Returns 0 on success, -1 on error. */
+int crypto_ml_kem_768_decaps(const unsigned char *priv, size_t priv_len,
+                               const unsigned char *ct, size_t ct_len,
+                               unsigned char *ss_out);
+/* Deterministic PRNG for PQ keygen (replaces PQClean randombytes()). */
+void pq_drbg_init(const unsigned char *seed, size_t seed_len);
+int  pq_drbg_randombytes(unsigned char *buf, size_t len);
+void pq_drbg_zeroize(void);
+
+
+
+
 /* from crypto.h */
 
 
 /* Per-role derived key material (stored in secure memory) */
 typedef struct {
-    secure_buf_t private_key;  /* 32 bytes, mlock'd */
-    unsigned char public_key[32];
-    char pubkey_hex[65];       /* 64 hex chars + null */
-    char npub[128];            /* bech32 npub */
+    secure_buf_t private_key;   /* mlock'd, variable size per algorithm */
+    secure_buf_t public_key;    /* mlock'd, variable size per algorithm */
+    char pubkey_hex[8192];      /* hex-encoded public key (PQ pubkeys are large) */
+    char npub[128];             /* bech32 npub (secp256k1 only, empty for others) */
+    crypto_alg_t alg;           /* which algorithm this key was derived for */
     int valid;
 } derived_key_t;
 
@@ -333,6 +510,82 @@ char *crypto_sign_event(const key_store_t *store, int role_index, const char *ev
 void crypto_wipe(key_store_t *store);
 
 
+
+/* from alg_api.h */
+
+
+/* Check whether a verb is valid for an algorithm (algorithm-based enforcement).
+ * Returns ENFORCE_OK, ENFORCE_ERR_ALGORITHM, or ENFORCE_ERR_UNKNOWN_VERB.
+ * Does NOT check purpose — purpose is irrelevant for the new verbs. */
+int enforce_verb_algorithm(const char *verb, crypto_alg_t alg);
+
+/* secp256k1 Schnorr (BIP-340) sign arbitrary bytes.
+ * priv is 32-byte scalar, pub is 32-byte x-only pubkey, sig_out is 64 bytes.
+ * Hashes the message with SHA-256 before signing (like Nostr event signing).
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_schnorr_sign(const unsigned char *priv, size_t priv_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 Schnorr (BIP-340) verify.
+ * pub is 32-byte x-only pubkey, sig is 64 bytes.
+ * Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_schnorr_verify(const unsigned char *pub, size_t pub_len,
+                                      const unsigned char *msg, size_t msg_len,
+                                      const unsigned char *sig, size_t sig_len);
+
+/* secp256k1 ECDSA sign arbitrary bytes.
+ * priv is 32-byte scalar, sig_out must be at least 64 bytes (compact DER r||s).
+ * Hashes the message with SHA-256 before signing.
+ * Returns 0 on success, -1 on error. */
+int crypto_secp256k1_ecdsa_sign(const unsigned char *priv, size_t priv_len,
+                                  const unsigned char *msg, size_t msg_len,
+                                  unsigned char *sig_out, size_t *sig_out_len);
+
+/* secp256k1 ECDSA verify.
+ * pub is 32-byte x-only pubkey (converted internally to compressed form).
+ * sig is 64-byte compact (r||s). Returns 0 on valid, 1 on invalid, -1 on error. */
+int crypto_secp256k1_ecdsa_verify(const unsigned char *pub, size_t pub_len,
+                                    const unsigned char *msg, size_t msg_len,
+                                    const unsigned char *sig, size_t sig_len);
+
+/* ---- Algorithm key cache ----
+ * On-demand key derivation by algorithm+index, separate from the role-based
+ * key_store. Holds up to ALG_KEY_CACHE_MAX derived keys in secure memory.
+ * When full, the oldest entry is evicted (FIFO). */
+
+#define ALG_KEY_CACHE_MAX 32
+
+typedef struct {
+    crypto_alg_t alg;
+    int index;
+    secure_buf_t private_key;
+    secure_buf_t public_key;
+    char pubkey_hex[8192];
+    char key_id[17];
+    int valid;
+} alg_key_entry_t;
+
+typedef struct {
+    alg_key_entry_t entries[ALG_KEY_CACHE_MAX];
+    int count;
+} algorithm_key_cache_t;
+
+/* Initialize an empty cache. */
+void alg_key_cache_init(algorithm_key_cache_t *cache);
+
+/* Zeroize and free all entries. Idempotent. */
+void alg_key_cache_wipe(algorithm_key_cache_t *cache);
+
+/* Look up a cached entry by (alg, index). Returns NULL if not present. */
+const alg_key_entry_t *alg_key_cache_get(algorithm_key_cache_t *cache, crypto_alg_t alg, int index);
+
+/* Derive a key on-demand by (alg, index) and store it in the cache.
+ * Uses the standard derivation path for the algorithm.
+ * Returns 0 on success, -1 on error. */
+int alg_key_cache_derive(algorithm_key_cache_t *cache, const mnemonic_state_t *mnemonic, crypto_alg_t alg, int index);
+
+
 /* from dispatcher.h */
 
 
@@ -341,10 +594,11 @@ typedef struct {
     role_table_t *role_table;
     mnemonic_state_t *mnemonic;
     key_store_t *key_store;
+    algorithm_key_cache_t *alg_key_cache;  /* algorithm-based on-demand keys */
 } dispatcher_ctx_t;
 
 /* Initialize dispatcher context */
-void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store);
+void dispatcher_init(dispatcher_ctx_t *ctx, role_table_t *table, mnemonic_state_t *mnemonic, key_store_t *key_store, algorithm_key_cache_t *alg_key_cache);
 
 /*
  * Process a JSON-RPC request string and produce a JSON-RPC response string.

tools/http_test.py

@@ -0,0 +1,141 @@
+#!/usr/bin/env python3
+"""
+http_test.py — test the HTTP listener mode with curl-like requests.
+
+Starts nsigner in HTTP mode, sends requests via urllib, and verifies
+the responses.
+"""
+import json
+import os
+import subprocess
+import sys
+import time
+import urllib.request
+
+NSIGNER = "./build/nsigner"
+PAD_DIR = "/media/user/Music/pads"
+PAD_SPEC = "333e9902db839d9d"
+MNEMONIC_FILE = ".test_mnemonic"
+MNEMONIC_TMP = ".test_mnemonic_http.tmp"
+PORT = 11111
+
+
+def main():
+    # Reset pad offset
+    state_path = f"{PAD_DIR}/333e9902db839d9d7f1f6aaa30f392a77c9abd011dd6274d9d3cf167361a789e.state"
+    with open(state_path, "w") as f:
+        f.write("offset=32\n")
+
+    # Prepare mnemonic temp file
+    with open(MNEMONIC_FILE) as f:
+        mnemonic = f.read().strip()
+    with open(MNEMONIC_TMP, "w") as f:
+        f.write(mnemonic + "\n")
+
+    # Start nsigner in HTTP mode
+    shell_cmd = (
+        f"exec 3<{MNEMONIC_TMP} 2>/dev/null; "
+        f"exec {NSIGNER} --listen http:127.0.0.1:{PORT} --mnemonic-fd 3 "
+        f"--otp-pad-dir {PAD_DIR} --otp-pad {PAD_SPEC} "
+        f"--otp-allow-blkback --allow-all"
+    )
+    proc = subprocess.Popen(
+        ["bash", "-c", shell_cmd],
+        stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
+    )
+    time.sleep(2.0)  # let the signer start
+
+    if proc.poll() is not None:
+        err = proc.stderr.read().decode()
+        print(f"ERROR: nsigner exited early (code {proc.returncode})")
+        print(f"stderr: {err}")
+        try:
+            os.unlink(MNEMONIC_TMP)
+        except OSError:
+            pass
+        return 1
+
+    try:
+        url = f"http://127.0.0.1:{PORT}/"
+
+        # Test 1: get_public_key
+        print("=== Test 1: get_public_key via HTTP ===")
+        req_data = json.dumps({
+            "id": "1",
+            "method": "get_public_key",
+            "params": [{"role": "main"}],
+        }).encode()
+        req = urllib.request.Request(url, data=req_data,
+                                      headers={"Content-Type": "application/json"})
+        with urllib.request.urlopen(req, timeout=5) as resp:
+            result = json.loads(resp.read().decode())
+        print(f"Response: {json.dumps(result)[:120]}...")
+        if "result" not in result:
+            print("ERROR: no result in get_public_key response")
+            return 1
+        pubkey = result["result"].strip('"')
+        print(f"Public key: {pubkey}")
+
+        # Test 2: otp_encrypt
+        print("\n=== Test 2: otp_encrypt via HTTP ===")
+        import base64
+        pt_b64 = base64.b64encode(b"Hello, OTP via HTTP!").decode()
+        req_data = json.dumps({
+            "id": "2",
+            "method": "otp_encrypt",
+            "params": [pt_b64, {"encoding": "ascii"}],
+        }).encode()
+        req = urllib.request.Request(url, data=req_data,
+                                      headers={"Content-Type": "application/json"})
+        with urllib.request.urlopen(req, timeout=5) as resp:
+            result = json.loads(resp.read().decode())
+        print(f"Response: {json.dumps(result)[:200]}...")
+        if "result" not in result:
+            print("ERROR: no result in otp_encrypt response")
+            return 1
+        enc_result = json.loads(result["result"])
+        ciphertext = enc_result["ciphertext"]
+        print(f"Pad offset: {enc_result['pad_offset_before']} -> {enc_result['pad_offset_after']}")
+        print(f"Ciphertext (first 60 chars): {ciphertext[:60]}...")
+
+        # Test 3: otp_decrypt
+        print("\n=== Test 3: otp_decrypt via HTTP ===")
+        req_data = json.dumps({
+            "id": "3",
+            "method": "otp_decrypt",
+            "params": [ciphertext, {"encoding": "ascii"}],
+        }).encode()
+        req = urllib.request.Request(url, data=req_data,
+                                      headers={"Content-Type": "application/json"})
+        with urllib.request.urlopen(req, timeout=5) as resp:
+            result = json.loads(resp.read().decode())
+        print(f"Response: {json.dumps(result)[:200]}...")
+        if "result" not in result:
+            print("ERROR: no result in otp_decrypt response")
+            return 1
+        dec_result = json.loads(result["result"])
+        recovered = base64.b64decode(dec_result["plaintext"]).decode()
+        print(f"Recovered plaintext: {recovered}")
+
+        if recovered == "Hello, OTP via HTTP!":
+            print("\n=== HTTP ROUND-TRIP SUCCESS ===")
+            return 0
+        else:
+            print("\n=== HTTP ROUND-TRIP FAILED ===")
+            print(f"Expected: Hello, OTP via HTTP!")
+            print(f"Got:      {recovered}")
+            return 1
+    finally:
+        proc.terminate()
+        try:
+            proc.wait(timeout=3)
+        except subprocess.TimeoutExpired:
+            proc.kill()
+        try:
+            os.unlink(MNEMONIC_TMP)
+        except OSError:
+            pass
+
+
+if __name__ == "__main__":
+    sys.exit(main())

tools/make_test_pad.c

@@ -0,0 +1,228 @@
+/*
+ * make_test_pad.c — generate a small test OTP pad on a target directory.
+ *
+ * Bit-compatible with the `otp` project's pad format:
+ *   - <chksum>.pad : raw random bytes, first 32 bytes are the "reserved header"
+ *     (also used as the key to encrypt the checksum).
+ *   - <chksum>.state : text file "offset=32\n" (32-byte header reserved).
+ *   - chksum is the 64-hex-char XOR checksum as computed by
+ *     otp/src/crypto.c:calculate_checksum (position-dependent XOR folded into
+ *     32 buckets, then XORed with the first 32 pad bytes).
+ *
+ * Usage:
+ *   make_test_pad <pad_dir> <size_bytes>
+ *
+ * Example:
+ *   make_test_pad /media/user/USBDISK/pads 1048576
+ *
+ * Entropy source: /dev/urandom (local-entropy test path only — NOT for production
+ * pads; production pads should use the `otp` CLI with keyboard/TRNG entropy or a
+ * future hardware signer).
+ */
+
+#define _POSIX_C_SOURCE 200809L
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <errno.h>
+
+#define CHKSUM_HEX_LEN 64
+#define CHKSUM_BIN_LEN 32
+#define HEADER_RESERVED 32
+#define BUF_SIZE (64 * 1024)
+
+static int compute_checksum(const char *pad_path, char *checksum_hex) {
+    FILE *file = fopen(pad_path, "rb");
+    if (!file) {
+        fprintf(stderr, "compute_checksum: cannot open %s: %s\n",
+                pad_path, strerror(errno));
+        return 1;
+    }
+
+    unsigned char checksum[CHKSUM_BIN_LEN];
+    unsigned char buffer[BUF_SIZE];
+    size_t bytes_read;
+    size_t total_bytes = 0;
+
+    memset(checksum, 0, CHKSUM_BIN_LEN);
+
+    while ((bytes_read = fread(buffer, 1, sizeof(buffer), file)) > 0) {
+        for (size_t i = 0; i < bytes_read; i++) {
+            size_t pos = total_bytes + i;
+            unsigned char bucket = (unsigned char)(pos % CHKSUM_BIN_LEN);
+            checksum[bucket] ^= buffer[i] ^
+                               (unsigned char)((pos >> 8) & 0xFF) ^
+                               (unsigned char)((pos >> 16) & 0xFF) ^
+                               (unsigned char)((pos >> 24) & 0xFF);
+        }
+        total_bytes += bytes_read;
+    }
+    fclose(file);
+
+    /* XOR the checksum with the first 32 bytes of the pad (the "pad key"). */
+    file = fopen(pad_path, "rb");
+    if (!file) {
+        fprintf(stderr, "compute_checksum: cannot reopen %s: %s\n",
+                pad_path, strerror(errno));
+        return 1;
+    }
+    unsigned char pad_key[CHKSUM_BIN_LEN];
+    if (fread(pad_key, 1, CHKSUM_BIN_LEN, file) != CHKSUM_BIN_LEN) {
+        fprintf(stderr, "compute_checksum: pad too small for header key\n");
+        fclose(file);
+        return 1;
+    }
+    fclose(file);
+
+    unsigned char encrypted_checksum[CHKSUM_BIN_LEN];
+    for (int i = 0; i < CHKSUM_BIN_LEN; i++) {
+        encrypted_checksum[i] = checksum[i] ^ pad_key[i];
+    }
+
+    for (int i = 0; i < CHKSUM_BIN_LEN; i++) {
+        sprintf(checksum_hex + (i * 2), "%02x", encrypted_checksum[i]);
+    }
+    checksum_hex[CHKSUM_HEX_LEN] = '\0';
+    return 0;
+}
+
+static int write_random(const char *path, size_t size) {
+    int urand = open("/dev/urandom", O_RDONLY);
+    if (urand < 0) {
+        fprintf(stderr, "cannot open /dev/urandom: %s\n", strerror(errno));
+        return 1;
+    }
+
+    int out = open(path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
+    if (out < 0) {
+        fprintf(stderr, "cannot create %s: %s\n", path, strerror(errno));
+        close(urand);
+        return 1;
+    }
+
+    unsigned char buffer[BUF_SIZE];
+    size_t written = 0;
+    while (written < size) {
+        size_t chunk = size - written;
+        if (chunk > sizeof(buffer)) chunk = sizeof(buffer);
+
+        ssize_t got = 0;
+        while ((size_t)got < chunk) {
+            ssize_t r = read(urand, buffer + got, chunk - (size_t)got);
+            if (r < 0) {
+                if (errno == EINTR) continue;
+                fprintf(stderr, "read urandom failed: %s\n", strerror(errno));
+                close(out);
+                close(urand);
+                return 1;
+            }
+            if (r == 0) {
+                fprintf(stderr, "urandom EOF (unexpected)\n");
+                close(out);
+                close(urand);
+                return 1;
+            }
+            got += r;
+        }
+
+        ssize_t put = 0;
+        while (put < got) {
+            ssize_t w = write(out, buffer + put, (size_t)got - (size_t)put);
+            if (w < 0) {
+                if (errno == EINTR) continue;
+                fprintf(stderr, "write %s failed: %s\n", path, strerror(errno));
+                close(out);
+                close(urand);
+                return 1;
+            }
+            put += w;
+        }
+        written += (size_t)got;
+    }
+
+    close(out);
+    close(urand);
+    return 0;
+}
+
+int main(int argc, char *argv[]) {
+    if (argc != 3) {
+        fprintf(stderr, "Usage: %s <pad_dir> <size_bytes>\n", argv[0]);
+        return 1;
+    }
+
+    const char *pad_dir = argv[1];
+    size_t size = (size_t)strtoull(argv[2], NULL, 10);
+    if (size < 64) {
+        fprintf(stderr, "size must be at least 64 bytes\n");
+        return 1;
+    }
+
+    /* Ensure pad_dir exists. */
+    struct stat st;
+    if (stat(pad_dir, &st) != 0) {
+        if (mkdir(pad_dir, 0755) != 0) {
+            fprintf(stderr, "cannot create %s: %s\n", pad_dir, strerror(errno));
+            return 1;
+        }
+    } else if (!S_ISDIR(st.st_mode)) {
+        fprintf(stderr, "%s exists but is not a directory\n", pad_dir);
+        return 1;
+    }
+
+    /* Write the pad to a temporary name first, then rename by checksum. */
+    char tmp_path[1024];
+    snprintf(tmp_path, sizeof(tmp_path), "%s/.tmp_pad_XXXXXX", pad_dir);
+    /* mkstemp would be cleaner, but we want a stable name for the rename. */
+    int tfd = mkstemp(tmp_path);
+    if (tfd < 0) {
+        fprintf(stderr, "mkstemp failed: %s\n", strerror(errno));
+        return 1;
+    }
+    close(tfd);
+
+    if (write_random(tmp_path, size) != 0) {
+        unlink(tmp_path);
+        return 1;
+    }
+
+    char chksum[CHKSUM_HEX_LEN + 1];
+    if (compute_checksum(tmp_path, chksum) != 0) {
+        unlink(tmp_path);
+        return 1;
+    }
+
+    char final_path[1024];
+    char state_path[1024];
+    snprintf(final_path, sizeof(final_path), "%s/%s.pad", pad_dir, chksum);
+    snprintf(state_path, sizeof(state_path), "%s/%s.state", pad_dir, chksum);
+
+    if (rename(tmp_path, final_path) != 0) {
+        fprintf(stderr, "rename %s -> %s failed: %s\n",
+                tmp_path, final_path, strerror(errno));
+        unlink(tmp_path);
+        return 1;
+    }
+
+    /* Write initial state file: offset=32 (header reserved). */
+    FILE *state = fopen(state_path, "w");
+    if (!state) {
+        fprintf(stderr, "cannot create %s: %s\n", state_path, strerror(errno));
+        return 1;
+    }
+    fprintf(state, "offset=%d\n", HEADER_RESERVED);
+    fclose(state);
+
+    printf("Created test pad:\n");
+    printf("  pad:   %s\n", final_path);
+    printf("  state: %s\n", state_path);
+    printf("  size:  %zu bytes\n", size);
+    printf("  chksum: %s\n", chksum);
+    printf("  chksum prefix (16 chars): %.16s\n", chksum);
+    return 0;
+}