public bool Check(string passphrase, BitcoinAddress expectedAddress)
{
//Derive passfactor using scrypt with ownerentropy and the user's passphrase and use it to recompute passpoint
byte[] passfactor = BitcoinEncryptedSecretEC.CalculatePassFactor(passphrase, LotSequence, OwnerEntropy);
//Derive decryption key for pointb using scrypt with passpoint, addresshash, and ownerentropy
byte[] passpoint = BitcoinEncryptedSecretEC.CalculatePassPoint(passfactor);
byte[] derived = BitcoinEncryptedSecretEC.CalculateDecryptionKey(passpoint, AddressHash, OwnerEntropy);
//Decrypt encryptedpointb to yield pointb
var pointbprefix = EncryptedPointB[0];
pointbprefix = (byte)(pointbprefix ^ (byte)(derived[63] & (byte)0x01));
//Optional since ArithmeticException will catch it, but it saves some times
if (pointbprefix != 0x02 && pointbprefix != 0x03)
{
return(false);
}
var pointb = BitcoinEncryptedSecret.DecryptKey(EncryptedPointB.Skip(1).ToArray(), derived);
pointb = new byte[] { pointbprefix }.Concat(pointb).ToArray();
//4.ECMultiply pointb by passfactor. Use the resulting EC point as a public key
var curve = ECKey.Secp256k1;
ECPoint pointbec;
try
{
pointbec = curve.Curve.DecodePoint(pointb);
}
catch (ArgumentException)
{
return(false);
}
catch (ArithmeticException)
{
return(false);
}
PubKey pubkey = new PubKey(pointbec.Multiply(new BigInteger(1, passfactor)).GetEncoded());
//and hash it into address using either compressed or uncompressed public key methodology as specifid in flagbyte.
pubkey = IsCompressed ? pubkey.Compress() : pubkey.Decompress();
var actualhash = BitcoinEncryptedSecretEC.HashAddress(pubkey.GetAddress(ScriptPubKeyType.Legacy, Network));
var expectedhash = BitcoinEncryptedSecretEC.HashAddress(expectedAddress);
return(Utils.ArrayEqual(actualhash, expectedhash));
}
