softDerive method

(SchnorrkelSecretKey, List<int>) softDerive(List<int> chainCode, { List<int>? message, GenerateRandom? nonceGenerator, })

Derives a new Schnorrkel secret key and chain code from the current secret key, chain code, and an optional message.

Parameters:

• chainCode: A chain code used in the derivation.
• message (optional): An optional byte array message used in the derivation. Default is an empty byte array.
• nonceGenerator (optional): A function that generates a nonce. Default is a function that generates a random 32-byte nonce.

Implementation

(SchnorrkelSecretKey, List<int>) softDerive(
  List<int> chainCode, {
  List<int>? message,
  GenerateRandom? nonceGenerator,
}) {
  final derivePub = publicKey()._deriveScalarAndChainCode(chainCode, message);
  final nonce =
      nonceGenerator?.call(SchnorrkelKeyCost.nonceLength) ??
      QuickCrypto.generateRandom(SchnorrkelKeyCost.nonceLength);
  if (nonce.length != SchnorrkelKeyCost.nonceLength) {
    throw const CryptoException("invalid none length.");
  }
  final newKey = Ed25519Utils.add(key(), derivePub.$1);
  final combine = [...newKey, ...nonce];
  return (SchnorrkelSecretKey.fromBytes(combine), derivePub.$2);
}