// 5.3 pg 28
/**
* Generate a signature for the given message using the key we were
* initialised with. For conventional DSA the message should be a SHA-1
* hash of the message of interest.
*
* @param message the message that will be verified later.
*/
public BigInteger[] GenerateSignature(byte[] message)
{
ECDomainParameters ec = key.Parameters;
BigInteger n = ec.N;
BigInteger e = calculateE(n, message);
BigInteger d = ((ECPrivateKeyParameters)key).D;
BigInteger r, s;
ECMultiplier basePointMultiplier = new FixedPointCombMultiplier();
// 5.3.2
do // Generate s
{
BigInteger k;
do // Generate r
{
do
{
k = new BigInteger(n.BitLength, random);
}
while (k.SignValue == 0 || k.CompareTo(n) >= 0);
ECPoint p = basePointMultiplier.Multiply(ec.G, k).Normalize();
// 5.3.3
r = p.AffineXCoord.ToBigInteger().Mod(n);
}
while (r.SignValue == 0);
s = k.ModInverse(n).Multiply(e.Add(d.Multiply(r))).Mod(n);
}
while (s.SignValue == 0);
return new BigInteger[]{ r, s };
}
/**
* generate a signature for the given message using the key we were
* initialised with. For conventional GOST3410 the message should be a GOST3411
* hash of the message of interest.
*
* @param message the message that will be verified later.
*/
public BigInteger[] GenerateSignature(
byte[] message)
{
byte[] mRev = new byte[message.Length]; // conversion is little-endian
for (int i = 0; i != mRev.Length; i++)
{
mRev[i] = message[mRev.Length - 1 - i];
}
BigInteger e = new BigInteger(1, mRev);
ECDomainParameters ec = key.Parameters;
BigInteger n = ec.N;
BigInteger d = ((ECPrivateKeyParameters)key).D;
BigInteger r, s = null;
ECMultiplier basePointMultiplier = new FixedPointCombMultiplier();
do // generate s
{
BigInteger k;
do // generate r
{
do
{
k = new BigInteger(n.BitLength, random);
}
while (k.SignValue == 0);
ECPoint p = basePointMultiplier.Multiply(ec.G, k).Normalize();
r = p.AffineXCoord.ToBigInteger().Mod(n);
}
while (r.SignValue == 0);
s = (k.Multiply(e)).Add(d.Multiply(r)).Mod(n);
}
while (s.SignValue == 0);
return new BigInteger[]{ r, s };
}