nonceAgg static method

List<int> nonceAgg(List<List<int>> pubnonces)

Aggregates public nonces for MuSig2

Implementation

static List<int> nonceAgg(List<List<int>> pubnonces) {
  if (pubnonces.length < MuSig2Const.minimumRequiredKey) {
    throw MuSig2Exception(
        "At least two public nonces are required for aggregation.");
  }
  for (final i in pubnonces) {
    if (i.length != MuSig2Const.pubnonceLength) {
      throw MuSig2Exception("Invalid public nonce length.", details: {
        "excpected": MuSig2Const.pubnonceLength,
        "length": i.length
      });
    }
  }
  final nonce = DynamicByteTracker();
  for (int i = 1; i < 3; i++) {
    ProjectiveECCPoint? rJ;
    for (final n in pubnonces) {
      final offset = (i - 1) * EcdsaKeysConst.pubKeyCompressedByteLen;
      final key = MuSig2Utils.encodePointAsEven(
          n.sublist(offset, offset + EcdsaKeysConst.pubKeyCompressedByteLen));
      if (rJ != null) {
        rJ = (rJ + key).cast();
      } else {
        rJ = key;
      }
    }
    if (rJ!.isInfinity) {
      nonce.add(MuSig2Const.zero);
    } else {
      nonce.add(rJ.toBytes());
    }
  }

  return nonce.toBytes();
}