public HdKey Derive(uint index)
{
var keyArray = Key.ToByteArray();
var pubKeyArray = PubKey.ToByteArray();
var data = (index & Hardened) != Hardened
? pubKeyArray
: ByteArray.Zero.Concat(keyArray);
var salt = Packer.Pack("A^I", data, index);
var i = Hashes.HMACSHA512(ChainCode, salt);
var il = i.Slice(0, KeyLength);
var ir = i.Slice(KeyLength, ChainCodeLength);
Key.CheckValidKey(il);
var parse256il = il.ToBigIntegerUnsigned(true);
var kpar = keyArray.ToBigIntegerUnsigned(true);
var childCodeChain = ir;
var childKey = (parse256il + kpar) % Secp256k1.N;
var keyBytes = childKey.ToUByteArray().ToBigEndian();
keyBytes = keyBytes.PadLeft(KeyLength);
var childFingerprint = PubKey.Hash.ToByteArray().Slice(0, FingerprintLength);
return(new HdKey(new Key(keyBytes), childCodeChain, (byte)(Depth + 1), index, childFingerprint));
}
public HdPubKey Derive(uint index)
{
if ((index & Hardened) == Hardened)
{
throw new InvalidOperationException("Cannot create a hardened child key from public child derivation");
}
var pubKey = PubKey.ToByteArray();
var salt = Packer.Pack("bA^I", pubKey[0], pubKey.Slice(1), index);
var i = Hashes.HMACSHA512(ChainCode, salt);
var il = i.Slice(0, KeyLength);
var ir = i.Slice(KeyLength, ChainCodeLength);
var childCodeChain = ir;
Key.CheckValidKey(il);
var parse256il = il.ToBigIntegerUnsigned(true);
var q = (Secp256k1.G * parse256il) + PubKey.Point;
if (q.IsInfinity)
{
throw new InvalidOperationException("Point is infinity, very rare. This event has a probability lower than 1 in 2^127");
}
var childFingerprint = PubKey.Hash.ToByteArray().Slice(0, FingerprintLength);
return(new HdPubKey(new PubKey(q.Encode(true)), childCodeChain, (byte)(Depth + 1), index, childFingerprint));
}
public KeyId(PubKey pubKey)
: this(Hashes.Hash160(pubKey.ToByteArray()))
{
}
public static Script FromPubKey(PubKey publicKey)
{
var pubKey = Encoders.Hex.GetString(publicKey.ToByteArray());
return(FromAsm($"{pubKey} OP_CHECKSIG"));
}
public byte[] ToByteArray()
{
return(Packer.Pack("bA^I_AA", Depth, Fingerprint, Child, ChainCode, PubKey.ToByteArray()));
}
