Simplify nip 55 (#2363)

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greenart7c3
2026-06-03 19:22:26 -03:00
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parent 2ab507db10
commit 6d72ea844f

623
55.md
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@@ -6,13 +6,31 @@ Android Signer Application
`draft` `optional`
This NIP describes a method for 2-way communication between an Android signer and any Nostr client on Android. The Android signer is an Android Application and the client can be a web client or an Android application.
## Rationale
## Usage for Android applications
This NIP describes a method for 2-way communication between an Android signer and any Nostr client running on the same device, so that the client never needs to handle the user's private key. The signer is an Android application; the client may be another Android application or a web page.
The Android signer uses Intents (to accept/reject permissions manually) and Content Resolvers (to accept/reject permissions automatically in background if the user allowed it) to communicate between applications.
## Terminology
To be able to use the Android signer in your application you should add this to your AndroidManifest.xml:
- **user**: A person trying to use Nostr.
- **client**: A user-facing application that sends signing requests.
- **signer**: An Android application that holds the user's private key and answers requests from _client_.
- **user-pubkey**: The public key representing _user_, returned by `get_public_key`.
- **package name**: The Android package name of the _signer_ (e.g. `com.example.signer`), used by _client_ to address subsequent requests.
All pubkeys in this NIP are in hex format.
## Communication methods
A _client_ can talk to the _signer_ in three ways:
- **Intents** — used by Android clients. The _signer_ opens, the _user_ approves or rejects the request manually, and the result is returned to _client_.
- **Content Resolver** — used by Android clients. Runs in the background without opening the _signer_, but only works for permissions the _user_ has previously chosen to remember.
- **Web** — used by web clients. The result is returned via a `callbackUrl` or copied to the clipboard.
## Setup
To detect and call the _signer_, an Android _client_ must declare the `nostrsigner` scheme in its `AndroidManifest.xml`:
```xml
<queries>
@@ -24,514 +42,148 @@ To be able to use the Android signer in your application you should add this to
</queries>
```
Then you can use this function to check if there's a signer application installed:
It can then check whether a _signer_ is installed:
```kotlin
fun isExternalSignerInstalled(context: Context): Boolean {
val intent =
Intent().apply {
action = Intent.ACTION_VIEW
data = Uri.parse("nostrsigner:")
}
val infos = context.packageManager.queryIntentActivities(intent, 0)
return infos.size > 0
val intent = Intent(Intent.ACTION_VIEW, Uri.parse("nostrsigner:"))
return context.packageManager.queryIntentActivities(intent, 0).isNotEmpty()
}
```
### Using Intents
## Initiating a connection
To get the result back from the Signer Application you should use `registerForActivityResult` or `rememberLauncherForActivityResult` in Kotlin. If you are using another framework check the documentation of your framework or a third party library to get the result.
1. _client_ sends a `get_public_key` request.
2. _signer_ responds with the `user-pubkey` and its `package name`.
3. _client_ stores both, and SHOULD NOT call `get_public_key` again while the _user_ stays logged in.
4. _client_ addresses all further requests to that `package name`.
```kotlin
val launcher = rememberLauncherForActivityResult(
contract = ActivityResultContracts.StartActivityForResult(),
onResult = { result ->
if (result.resultCode != Activity.RESULT_OK) {
Toast.makeText(
context,
"Sign request rejected",
Toast.LENGTH_SHORT
).show()
} else {
val result = activityResult.data?.getStringExtra("result")
// Do something with result ...
}
}
)
A _client_ MAY pass a list of `permissions` with `get_public_key` so the _user_ can pre-authorize methods (used by the Content Resolver to answer in the background). Each permission is an object with a `type` (a method name) and, for `sign_event`, an optional `kind`:
```json
[{ "type": "sign_event", "kind": 22242 }, { "type": "nip44_decrypt" }]
```
Create the Intent using the **nostrsigner** scheme:
```kotlin
val intent = Intent(Intent.ACTION_VIEW, Uri.parse("nostrsigner:$content"))
```
Set the Signer package name after you receive the response from **get_public_key** method:
```kotlin
intent.`package` = "com.example.signer"
```
If you are sending multiple intents without awaiting you can add some intent flags to sign all events without opening multiple times the signer
```kotlin
intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP or Intent.FLAG_ACTIVITY_CLEAR_TOP)
```
If you are developing a signer application them you need to add this to your AndroidManifest.xml so clients can use the intent flags above
```kotlin
android:launchMode="singleTop"
```
Signer MUST answer multiple permissions with an array of results
```kotlin
val results = listOf(
Result(
package = signerPackageName,
result = eventSignature,
id = intentId
)
)
val json = results.toJson()
intent.putExtra("results", json)
```
Send the Intent:
## Methods
Every request has a `type` (the method name) and a payload. The payload is passed differently per transport (see below) but its meaning is shared:
| Method | Payload | Extra params | Result |
| ------------------- | --------------- | ------------------------- | ------------------------------- |
| `get_public_key` | _(empty)_ | `permissions` | `user-pubkey` |
| `sign_event` | event JSON | `current_user` | the signature, and signed event |
| `nip04_encrypt` | plaintext | `pubkey`, `current_user` | the ciphertext |
| `nip44_encrypt` | plaintext | `pubkey`, `current_user` | the ciphertext |
| `nip04_decrypt` | ciphertext | `pubkey`, `current_user` | the plaintext |
| `nip44_decrypt` | ciphertext | `pubkey`, `current_user` | the plaintext |
| `decrypt_zap_event` | event JSON | `current_user` | the decrypted event JSON |
- `current_user` is the `user-pubkey` currently logged in to _client_, in hex format.
- `pubkey` is the public key of the other party used for encryption/decryption, in hex format.
- `id` is an optional client-chosen string echoed back in the result, used to match responses when several requests are sent without waiting.
## Using Intents
The payload is the `nostrsigner:` URI data; all other params are intent extras. The result is returned via `registerForActivityResult` / `rememberLauncherForActivityResult`.
```kotlin
val intent = Intent(Intent.ACTION_VIEW, Uri.parse("nostrsigner:$payload")).apply {
`package` = signerPackageName // omit only for get_public_key
putExtra("type", "sign_event")
putExtra("id", event.id) // optional, echoed back
putExtra("current_user", userPubkey)
}
launcher.launch(intent)
```
### Initiating a connection
The result is read from the returned intent's extras:
- Client send a get_public_key `Intent`
- Signer responds with the user `pubkey` and it's `packageName`
- Client saves the `pubkey` and `packageName` somewhere and NEVER calls `get_public_key` again
- Client now can send `content resolvers` and `Intents` for the other methods
| Extra | Description |
| ---------- | -------------------------------------------------------- |
| `result` | the method result (pubkey, signature, ciphertext, etc.) |
| `id` | the `id` sent in the request |
| `event` | the signed event JSON (`sign_event` only) |
| `package` | the _signer_ package name (`get_public_key` only) |
| `rejected` | `true` when the _user_ rejected the request |
#### Methods
A `resultCode` other than `Activity.RESULT_OK` means the _signer_ failed (e.g. it crashed), not that the _user_ rejected the request. When the _user_ rejects, the _signer_ returns `RESULT_OK` with a `rejected` extra set to `true`.
- **get_public_key**
- params:
```kotlin
onResult = { result ->
if (result.resultCode != Activity.RESULT_OK) {
// signer error (e.g. crash)
} else if (result.data?.getBooleanExtra("rejected", false) == true) {
// user rejected the request
} else {
val value = result.data?.getStringExtra("result")
}
}
```
```kotlin
val intent = Intent(Intent.ACTION_VIEW, Uri.parse("nostrsigner:"))
intent.putExtra("type", "get_public_key")
// You can send some default permissions for the user to authorize for ever
val permissions = listOf(
Permission(
type = "sign_event",
kind = 22242
),
Permission(
type = "nip44_decrypt"
)
)
intent.putExtra("permissions", permissions.toJson())
context.startActivity(intent)
```
- result:
- If the user approved the intent it will return the **pubkey** in the result field and the signer packageName in the **package** field
To sign multiple events without reopening the _signer_ for each one, _client_ adds the flags below and the _signer_ returns an array of results. The _signer_ must declare `android:launchMode="singleTop"` for this to work.
```kotlin
val pubkey = intent.data?.getStringExtra("result")
// The package name of the signer application
val packageName = intent.data?.getStringExtra("package")
```
```kotlin
intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP or Intent.FLAG_ACTIVITY_CLEAR_TOP)
- **sign_event**
- params:
// signer answers with:
intent.putExtra("results", listOf(Result(package = signerPackageName, result = signature, id = intentId)).toJson())
```
```kotlin
val intent = Intent(Intent.ACTION_VIEW, Uri.parse("nostrsigner:$eventJson"))
intent.`package` = "com.example.signer"
intent.putExtra("type", "sign_event")
// To handle results when not waiting between intents
intent.putExtra("id", event.id)
// Send the current logged in user pubkey
intent.putExtra("current_user", pubkey)
## Using Content Resolver
context.startActivity(intent)
```
- result:
- If the user approved intent it will return the **result**, **id** and **event** fields
The _client_ queries `content://<package-name>.<TYPE>` (e.g. `SIGN_EVENT`, `NIP44_ENCRYPT`). The query's `selectionArgs` carry the payload and params in the order `[payload, pubkey, current_user]`:
```kotlin
val signature = intent.data?.getStringExtra("result")
// The id you sent
val id = intent.data?.getStringExtra("id")
val signedEventJson = intent.data?.getStringExtra("event")
```
- **nip04_encrypt**
- params:
```kotlin
val intent = Intent(Intent.ACTION_VIEW, Uri.parse("nostrsigner:$plaintext"))
intent.`package` = "com.example.signer"
intent.putExtra("type", "nip04_encrypt")
// to control the result in your application in case you are not waiting the result before sending another intent
intent.putExtra("id", "some_id")
// Send the current logged in user pubkey
intent.putExtra("current_user", account.keyPair.pubkey)
// Send the hex pubkey that will be used for encrypting the data
intent.putExtra("pubkey", pubkey)
context.startActivity(intent)
```
- result:
- If the user approved intent it will return the **result** and **id** fields
```kotlin
val encryptedText = intent.data?.getStringExtra("result")
// the id you sent
val id = intent.data?.getStringExtra("id")
```
- **nip44_encrypt**
- params:
```kotlin
val intent = Intent(Intent.ACTION_VIEW, Uri.parse("nostrsigner:$plaintext"))
intent.`package` = "com.example.signer"
intent.putExtra("type", "nip44_encrypt")
// to control the result in your application in case you are not waiting the result before sending another intent
intent.putExtra("id", "some_id")
// Send the current logged in user pubkey
intent.putExtra("current_user", account.keyPair.pubkey)
// Send the hex pubkey that will be used for encrypting the data
intent.putExtra("pubkey", pubkey)
context.startActivity(intent)
```
- result:
- If the user approved intent it will return the **result** and **id** fields
```kotlin
val encryptedText = intent.data?.getStringExtra("result")
// the id you sent
val id = intent.data?.getStringExtra("id")
```
- **nip04_decrypt**
- params:
```kotlin
val intent = Intent(Intent.ACTION_VIEW, Uri.parse("nostrsigner:$encryptedText"))
intent.`package` = "com.example.signer"
intent.putExtra("type", "nip04_decrypt")
// to control the result in your application in case you are not waiting the result before sending another intent
intent.putExtra("id", "some_id")
// Send the current logged in user pubkey
intent.putExtra("current_user", account.keyPair.pubkey)
// Send the hex pubkey that will be used for decrypting the data
intent.putExtra("pubkey", pubkey)
context.startActivity(intent)
```
- result:
- If the user approved intent it will return the **result** and **id** fields
```kotlin
val plainText = intent.data?.getStringExtra("result")
// the id you sent
val id = intent.data?.getStringExtra("id")
```
- **nip44_decrypt**
- params:
```kotlin
val intent = Intent(Intent.ACTION_VIEW, Uri.parse("nostrsigner:$encryptedText"))
intent.`package` = "com.example.signer"
intent.putExtra("type", "nip44_decrypt")
// to control the result in your application in case you are not waiting the result before sending another intent
intent.putExtra("id", "some_id")
// Send the current logged in user pubkey
intent.putExtra("current_user", account.keyPair.pubkey)
// Send the hex pubkey that will be used for decrypting the data
intent.putExtra("pubkey", pubkey)
context.startActivity(intent)
```
- result:
- If the user approved intent it will return the **result** and **id** fields
```kotlin
val plainText = intent.data?.getStringExtra("result")
// the id you sent
val id = intent.data?.getStringExtra("id")
```
- **decrypt_zap_event**
- params:
```kotlin
val intent = Intent(Intent.ACTION_VIEW, Uri.parse("nostrsigner:$eventJson"))
intent.`package` = "com.example.signer"
intent.putExtra("type", "decrypt_zap_event")
// to control the result in your application in case you are not waiting the result before sending another intent
intent.putExtra("id", "some_id")
// Send the current logged in user pubkey
intent.putExtra("current_user", account.keyPair.pubkey)
context.startActivity(intent)
```
- result:
- If the user approved intent it will return the **result** and **id** fields
```kotlin
val eventJson = intent.data?.getStringExtra("result")
// the id you sent
val id = intent.data?.getStringExtra("id")
```
### Using Content Resolver
To get the result back from Signer Application you should use contentResolver.query in Kotlin. If you are using another framework check the documentation of your framework or a third party library to get the result.
If the user did not check the "remember my choice" option, the pubkey is not in Signer Application or the signer type is not recognized the `contentResolver` will return null
For the SIGN_EVENT type Signer Application returns two columns "result" and "event". The column event is the signed event json
For the other types Signer Application returns the column "result"
If the user chose to always reject the event, signer application will return the column "rejected" and you should not open signer application
Clients SHOULD save the user pubkey locally and avoid calling the `get_public_key` after the user is logged in to the Client
#### Methods
- **sign_event**
- params:
```kotlin
val result = context.contentResolver.query(
```kotlin
val result = context.contentResolver.query(
Uri.parse("content://com.example.signer.SIGN_EVENT"),
listOf("$eventJson", "", "${logged_in_user_pubkey}"),
null,
null,
null
)
```
- result:
- Will return the **result** and the **event** columns
listOf(eventJson, "", loggedInUserPubkey),
null, null, null,
)
```
```kotlin
if (result == null) return
The cursor returns a `result` column (and, for `sign_event`, an `event` column with the signed event JSON). The query returns `null`, or a `rejected` column is present, when:
if (it.getColumnIndex("rejected") > -1) return
- the _user_ did not enable "remember my choice" for this request,
- the `user-pubkey` is not present in the _signer_,
- the request `type` is not recognized, or
- the _user_ chose to always reject this request (a `rejected` column is returned — _client_ SHOULD NOT then fall back to an Intent).
if (result.moveToFirst()) {
val index = it.getColumnIndex("result")
val indexJson = it.getColumnIndex("event")
val signature = it.getString(index)
val eventJson = it.getString(indexJson)
}
```
```kotlin
if (result == null) return
if (result.getColumnIndex("rejected") > -1) return
if (result.moveToFirst()) {
val value = result.getString(result.getColumnIndex("result"))
// for sign_event also: result.getColumnIndex("event")
}
```
- **nip04_encrypt**
- params:
Clients SHOULD store the `user-pubkey` locally and avoid calling `get_public_key` after the user is logged in.
```kotlin
val result = context.contentResolver.query(
Uri.parse("content://com.example.signer.NIP04_ENCRYPT"),
listOf("$plainText", "${hex_pub_key}", "${logged_in_user_pubkey}"),
null,
null,
null
)
```
- result:
- Will return the **result** column
## Using Web Applications
```kotlin
if (result == null) return
Web clients can't receive a result from an intent, so the _signer_ returns the result via a `callbackUrl` (appended to the URL) or, if none is given, by copying it to the clipboard. The request is a `nostrsigner:` URL whose path is the payload and whose query string carries the params:
if (it.getColumnIndex("rejected") > -1) return
```
nostrsigner:<payload>?type=<method>&pubkey=<hex_pubkey>&callbackUrl=https://example.com/?result=
```
if (result.moveToFirst()) {
val index = it.getColumnIndex("result")
val encryptedText = it.getString(index)
}
```
Query parameters:
- **nip44_encrypt**
- params:
- `type` — the method name.
- `pubkey` — the other party's hex pubkey (encryption/decryption methods).
- `callbackUrl` — where the _signer_ appends the result. If omitted, the result is copied to the clipboard.
- `returnType``signature` or `event`.
- `compressionType``none` (default) or `gzip`. With `gzip` the returned event is `"Signer1"` + Base64(gzip(event json)); useful because intents and URLs have length limits.
```kotlin
val result = context.contentResolver.query(
Uri.parse("content://com.example.signer.NIP44_ENCRYPT"),
listOf("$plainText", "${hex_pub_key}", "${logged_in_user_pubkey}"),
null,
null,
null
)
```
- result:
- Will return the **result** column
```js
window.href = `nostrsigner:${eventJson}?compressionType=none&returnType=signature&type=sign_event&callbackUrl=https://example.com/?event=`;
```
```kotlin
if (result == null) return
if (it.getColumnIndex("rejected") > -1) return
if (result.moveToFirst()) {
val index = it.getColumnIndex("result")
val encryptedText = it.getString(index)
}
```
- **nip04_decrypt**
- params:
```kotlin
val result = context.contentResolver.query(
Uri.parse("content://com.example.signer.NIP04_DECRYPT"),
listOf("$encryptedText", "${hex_pub_key}", "${logged_in_user_pubkey}"),
null,
null,
null
)
```
- result:
- Will return the **result** column
```kotlin
if (result == null) return
if (it.getColumnIndex("rejected") > -1) return
if (result.moveToFirst()) {
val index = it.getColumnIndex("result")
val encryptedText = it.getString(index)
}
```
- **nip44_decrypt**
- params:
```kotlin
val result = context.contentResolver.query(
Uri.parse("content://com.example.signer.NIP44_DECRYPT"),
listOf("$encryptedText", "${hex_pub_key}", "${logged_in_user_pubkey}"),
null,
null,
null
)
```
- result:
- Will return the **result** column
```kotlin
if (result == null) return
if (it.getColumnIndex("rejected") > -1) return
if (result.moveToFirst()) {
val index = it.getColumnIndex("result")
val encryptedText = it.getString(index)
}
```
- **decrypt_zap_event**
- params:
```kotlin
val result = context.contentResolver.query(
Uri.parse("content://com.example.signer.DECRYPT_ZAP_EVENT"),
listOf("$eventJson", "", "${logged_in_user_pubkey}"),
null,
null,
null
)
```
- result:
- Will return the **result** column
```kotlin
if (result == null) return
if (it.getColumnIndex("rejected") > -1) return
if (result.moveToFirst()) {
val index = it.getColumnIndex("result")
val eventJson = it.getString(index)
}
```
## Usage for Web Applications
You should consider using [NIP-46: Nostr Connect](46.md) for a better experience for web applications. When using this approach, the web app can't call the signer in the background, so the user will see a popup for every event you try to sign.
Since web applications can't receive a result from the intent, you should add a modal to paste the signature or the event json or create a callback url.
If you send the callback url parameter, Signer Application will send the result to the url.
If you don't send a callback url, Signer Application will copy the result to the clipboard.
You can configure the `returnType` to be **signature** or **event**.
Android intents and browser urls have limitations, so if you are using the `returnType` of **event** consider using the parameter **compressionType=gzip** that will return "Signer1" + Base64 gzip encoded event json
### Methods
- **get_public_key**
- params:
```js
window.href = `nostrsigner:?compressionType=none&returnType=signature&type=get_public_key&callbackUrl=https://example.com/?event=`;
```
- **sign_event**
- params:
```js
window.href = `nostrsigner:${eventJson}?compressionType=none&returnType=signature&type=sign_event&callbackUrl=https://example.com/?event=`;
```
- **nip04_encrypt**
- params:
```js
window.href = `nostrsigner:${plainText}?pubkey=${hex_pub_key}&compressionType=none&returnType=signature&type=nip04_encrypt&callbackUrl=https://example.com/?event=`;
```
- **nip44_encrypt**
- params:
```js
window.href = `nostrsigner:${plainText}?pubkey=${hex_pub_key}&compressionType=none&returnType=signature&type=nip44_encrypt&callbackUrl=https://example.com/?event=`;
```
- **nip04_decrypt**
- params:
```js
window.href = `nostrsigner:${encryptedText}?pubkey=${hex_pub_key}&compressionType=none&returnType=signature&type=nip04_decrypt&callbackUrl=https://example.com/?event=`;
```
- **nip44_decrypt**
- params:
```js
window.href = `nostrsigner:${encryptedText}?pubkey=${hex_pub_key}&compressionType=none&returnType=signature&type=nip44_decrypt&callbackUrl=https://example.com/?event=`;
```
- **decrypt_zap_event**
- params:
```js
window.href = `nostrsigner:${eventJson}?compressionType=none&returnType=signature&type=decrypt_zap_event&callbackUrl=https://example.com/?event=`;
```
> Consider using [NIP-46: Nostr Remote Signing](46.md) for web applications. With the approach here the web client can't call the _signer_ in the background, so the _user_ sees a popup for every request.
### Example
```js
```html
<!DOCTYPE html>
<html lang="en">
<head>
@@ -544,21 +196,16 @@ Android intents and browser urls have limitations, so if you are using the `retu
<script>
window.onload = function() {
var url = new URL(window.location.href);
var params = url.searchParams;
if (params) {
var param1 = params.get("event");
if (param1) alert(param1)
}
let json = {
kind: 1,
content: "test"
}
let encodedJson = encodeURIComponent(JSON.stringify(json))
var newAnchor = document.createElement("a");
newAnchor.href = `nostrsigner:${encodedJson}?compressionType=none&returnType=signature&type=sign_event&callbackUrl=https://example.com/?event=`;
newAnchor.textContent = "Open External Signer";
document.body.appendChild(newAnchor)
var params = new URL(window.location.href).searchParams;
var result = params.get("event");
if (result) alert(result);
var json = { kind: 1, content: "test" };
var encodedJson = encodeURIComponent(JSON.stringify(json));
var anchor = document.createElement("a");
anchor.href = `nostrsigner:${encodedJson}?compressionType=none&returnType=signature&type=sign_event&callbackUrl=https://example.com/?event=`;
anchor.textContent = "Open External Signer";
document.body.appendChild(anchor);
}
</script>
</body>