public static void ECPrivateKeyToPublicKey(
BigInteger privateKey,
out BigInteger publicKeyX,
out BigInteger publicKeyY)
{
if (!EllipticCurve.IsPrivateKeyValid(privateKey))
{
throw new Exception("privateKey is invalid.");
}
var parameters = Org.BouncyCastle.Asn1.Sec.SecNamedCurves.GetByName("secp256k1");
var d = new Org.BouncyCastle.Math.BigInteger(privateKey.ToString());
var Q = parameters.G.Multiply(d).Normalize();
publicKeyX = BigInteger.Parse(Q.XCoord.ToBigInteger().ToString());
publicKeyY = BigInteger.Parse(Q.YCoord.ToBigInteger().ToString());
}
public static BigInteger PasswordToPrivateKey(string password)
{
// change salt for improved security
// reference https://en.wikipedia.org/wiki/Key_stretching
// reference https://en.wikipedia.org/wiki/Salt_(cryptography)
string salt = "Cryptography";
var pbkdf2 = new Rfc2898DeriveBytes(
Encoding.UTF8.GetBytes(password),
Encoding.UTF8.GetBytes(salt),
4096);
BigInteger privateKey = Encode.BytesToBigInteger(pbkdf2.GetBytes(32));
if (!EllipticCurve.IsPrivateKeyValid(privateKey))
{
throw new Exception("privateKey is invalid."); // extreme low probability to happen
}
return(privateKey);
}
