Key Pair

The God of sr25519 library. Combines whole logic into the one place.

On a low level has next constructor:

class KeyPair(
    val secretKey: SecretKey,
    val publicKey: PublicKey,
)

While you can use this knowing Secret Key and creating Public Key out of it, there are more popular ways to work with it.

Uniform

val secretKeyBytes: ByteArray
val publicKeyBytes: ByteArray
val keyPair: KeyPair = KeyPair.fromByteArray(secretKeyBytes + secretKeyBytes)
val secretKeyAndRistretto = keyPair.toByteArray()

ed25519

val secretKeyBytes: ByteArray
val publicKeyBytes: ByteArray
val keyPair: KeyPair = KeyPair.fromHalfEd25519ByteArray(secretKeyBytes + secretKeyBytes)
val secretKeyAndRistretto = keyPair.toHalfEd25519ByteArray()

Generation

Basically, proxies the call to internal Secret Key:

val generatedKeyPair: KeyPair = KeyPair.generate()

val yourSecureRandom: kotlin.random.Random
val generatedKeyPairWithCPSRNG: KeyPair = KeyPair.generateWith(yourSecureRandom)

Signing

Same proxying of signature methods to its Secret Key:

val yourContextLabel: String
val messageToSign: ByteArray

val signingContext: SigningContext = SigningContext
    .fromContext(yourContextLabel.toByteArray())
val signingTranscript: SigningTranscript = signingContext.bytes(messageToSign)
    
val yourKeyPair: KeyPair
val signedMessage: Signature = yourKeyPair.sign(signingTranscript)

Double check signature:

val signingTranscript: SigningTranscript
val yourKeyPair: KeyPair

val signedMessage: Signature = yourKeyPair.signDoubleCheck(signingTranscript)

Simple signing:

val yourContextLabel: String
val messageToSign: ByteArray

// Still, we need to set the context
val signingContext: SigningContext = SigningContext
    .fromContext(yourContextLabel.toByteArray())
    
val yourKeyPair: KeyPair
val signedMessage: Signature = yourKeyPair.signSimple(signingContext, messageToSign)
val doubleCheckedSignedMessage: Signature = yourKeyPair.signSimpleDoubleCheck(signingContext, messageToSign)

Uniform

Verifying

Now it has proxy methods for its internal Public Key:

val yourKeyPair: KeyPair
val message: ByteArray
val signedMessage: ByteArray

val signature: Signature = Signature.fromByteArray(signedMessage)

val signingContext: SigningContext = SigningContext
    .fromContext(yourContextLabel.toByteArray())

val simplyVerified: Boolean = yourKeyPair.verifySimple(signingContext, message, signature)

val signingTranscript: SigningTranscript = signingContext.bytes(message)
val verified: Boolean = yourKeyPair.verify(signingTranscript, signature)

// simplyVerified == verified