public string SignString(string contents, string privateKey)
{
var curve = SecNamedCurves.GetByName("secp256k1");
var domain = new ECDomainParameters(curve.Curve, curve.G, curve.N, curve.H);
var keyParameters = new ECPrivateKeyParameters(new BigInteger(privateKey, 16), domain);
Org.BouncyCastle.Crypto.ISigner signer = SignerUtilities.GetSigner("SHA-256withECDSA");
signer.Init(true, keyParameters);
signer.BlockUpdate(Encoding.ASCII.GetBytes(contents), 0, contents.Length);
var signature = signer.GenerateSignature();
return(Base58Encoding.Encode(signature));
}
public string GeneratePublicKey(string privateKey)
{
if (String.IsNullOrWhiteSpace(privateKey))
{
throw new FormatException("Empty private key");
}
var curve = SecNamedCurves.GetByName("secp256k1");
var domain = new ECDomainParameters(curve.Curve, curve.G, curve.N, curve.H);
var d = new BigInteger(privateKey, 16);
var q = domain.G.Multiply(d);
var publicKey = new ECPublicKeyParameters(q, domain);
return(Base58Encoding.Encode(publicKey.Q.GetEncoded()));
}
public bool SignatureIsValid(string signature, string contents, string publicKey)
{
var curve = SecNamedCurves.GetByName("secp256k1");
var domain = new ECDomainParameters(curve.Curve, curve.G, curve.N, curve.H);
var publicKeyBytes = Base58Encoding.Decode(publicKey);
var q = curve.Curve.DecodePoint(publicKeyBytes);
var keyParameters = new ECPublicKeyParameters(q, domain);
Org.BouncyCastle.Crypto.ISigner signer = SignerUtilities.GetSigner("SHA-256withECDSA");
signer.Init(false, keyParameters);
signer.BlockUpdate(Encoding.ASCII.GetBytes(contents), 0, contents.Length);
var signatureBytes = Base58Encoding.Decode(signature);
return(signer.VerifySignature(signatureBytes));
}