deterministicSign static method

MuSig2DeterministicSignature deterministicSign({ required List<int> sk, required List<int> aggotherNonce, required List<List<int>> publicKeys, List<MuSig2Tweak> tweaks = const [], required List<int> msg, List<int>? rand, })

Generates a deterministic MuSig2 signature

Implementation

static MuSig2DeterministicSignature deterministicSign(
    {required List<int> sk,
    required List<int> aggotherNonce,
    required List<List<int>> publicKeys,
    List<MuSig2Tweak> tweaks = const [],
    required List<int> msg,
    List<int>? rand}) {
  if (rand != null) {
    rand = BytesUtils.xor(
        sk, P2TRUtils.taggedHash(MuSig2Const.musigAuxDomain, rand));
  } else {
    rand = List<int>.from(sk);
  }
  final aggPk =
      MuSig2Utils.keyAggAndTweak(publicKeys: publicKeys, tweaks: tweaks);
  final aggPkX = aggPk.xOnly().asImmutableBytes;
  final k1 = MuSig2Utils.deterministicNonceHash(
          sk: rand,
          aggotherNonce: aggotherNonce,
          aggPk: aggPkX,
          i: 0,
          msg: msg) %
      MuSig2Const.order;
  final k2 = MuSig2Utils.deterministicNonceHash(
          sk: rand,
          aggotherNonce: aggotherNonce,
          aggPk: aggPkX,
          i: 1,
          msg: msg) %
      MuSig2Const.order;

  if (k1 == BigInt.zero || k2 == BigInt.zero) {
    throw MuSig2Exception("derive nonce hash failed.");
  }
  final rs1 = MuSig2Const.generator * k1;
  final rs2 = MuSig2Const.generator * k2;
  final pk = MuSig2Utils.scToPk(sk);
  final pubnonce = [...rs1.toBytes(), ...rs2.toBytes()];
  final secnonce = [
    ...BigintUtils.toBytes(k1, length: BigintUtils.bitlengthInBytes(k1)),
    ...BigintUtils.toBytes(k2, length: BigintUtils.bitlengthInBytes(k2)),
    ...pk
  ].asImmutableBytes;
  final aggnonce = nonceAgg([pubnonce, aggotherNonce]);
  final session = MuSig2Session(
      aggnonce: aggnonce, publicKeys: publicKeys, tweaks: tweaks, msg: msg);
  final signature = sign(secnonce: secnonce, sk: sk, session: session);
  return MuSig2DeterministicSignature(
      pubnonce: pubnonce, signature: signature);
}