public virtual byte[] GenerateSignature()
{
byte[] eHash = DigestUtilities.DoFinal(digest);
BigInteger n = ecParams.N;
BigInteger e = CalculateE(n, eHash);
BigInteger d = ((ECPrivateKeyParameters)ecKey).D;
BigInteger r, s;
ECMultiplier basePointMultiplier = CreateBasePointMultiplier();
// 5.2.1 Draft RFC: SM2 Public Key Algorithms
do // generate s
{
BigInteger k;
do // generate r
{
// A3
k = kCalculator.NextK();
// A4
ECPoint p = basePointMultiplier.Multiply(ecParams.G, k).Normalize();
// A5
r = e.Add(p.AffineXCoord.ToBigInteger()).Mod(n);
}while (r.SignValue == 0 || r.Add(k).Equals(n));
// A6
BigInteger dPlus1ModN = d.Add(BigInteger.One).ModInverse(n);
s = k.Subtract(r.Multiply(d)).Mod(n);
s = dPlus1ModN.Multiply(s).Mod(n);
}while (s.SignValue == 0);
// A7
try
{
return(encoding.Encode(ecParams.N, r, s));
}
catch (Exception ex)
{
throw new CryptoException("unable to encode signature: " + ex.Message, ex);
}
}
/**
* Generate a signature for the message we've been loaded with using
* the key we were initialised with.
*/
public virtual byte[] GenerateSignature()
{
if (!forSigning)
{
throw new InvalidOperationException("DSADigestSigner not initialised for signature generation.");
}
byte[] hash = new byte[digest.GetDigestSize()];
digest.DoFinal(hash, 0);
BigInteger[] sig = dsa.GenerateSignature(hash);
try
{
return(encoding.Encode(GetOrder(), sig[0], sig[1]));
}
catch (Exception)
{
throw new InvalidOperationException("unable to encode signature");
}
}