NIP-55 Android

A spec-compliant NIP-55 library for Android. Communicate with any external signer (Amber, Signet, etc.) to sign Nostr events without exposing private keys.

Watch demo

Installation

// settings.gradle.kts
dependencyResolutionManagement {
    repositories {
        maven { url = uri("https://jitpack.io") }
    }
}

// build.gradle.kts
dependencies {
    implementation("com.github.Letdown2491:nip55-android:1.0.0")
}

Add to AndroidManifest.xml (required for Android 11+):

<queries>
    <intent>
        <action android:name="android.intent.action.VIEW" />
        <data android:scheme="nostrsigner" />
    </intent>
</queries>

Quick Start

class MyActivity : AppCompatActivity() {

    private val getPublicKey = registerForActivityResult(GetPublicKeyContract()) { result ->
        result
            .onSuccess { login(it.pubkey) }
            .onError { showError(it.message) }
    }

    private val signEvent = registerForActivityResult(SignEventContract()) { result ->
        result
            .onSuccess { publish(it.signedEventJson) }
            .onError { showError(it.message) }
    }

    fun login() {
        if (!Nip55.isSignerAvailable(this)) return
        getPublicKey.launch(GetPublicKeyContract.Input())
    }

    fun sign(eventJson: String, userPubkey: String) {
        signEvent.launch(SignEventContract.Input(eventJson, userPubkey))
    }

    // Encrypt/decrypt (NIP-44)
    private val encrypt = registerForActivityResult(Nip44EncryptContract()) { result ->
        result.onSuccess { sendMessage(it.ciphertext) }
    }

    fun encryptMessage(plaintext: String, recipientPubkey: String, userPubkey: String) {
        encrypt.launch(Nip44EncryptContract.Input(plaintext, recipientPubkey, userPubkey))
    }
}

See API.md for all contracts and options.