public virtual byte[] Encode(BigInteger n, BigInteger r, BigInteger s)
{
int valueLength = BigIntegers.GetUnsignedByteLength(n);
byte[] result = new byte[valueLength * 2];
EncodeValue(n, r, result, 0, valueLength);
EncodeValue(n, s, result, valueLength, valueLength);
return(result);
}
public void Init(BigInteger n, BigInteger d, byte[] message)
{
this.n = n;
Arrays.Fill(V, (byte)0x01);
Arrays.Fill(K, (byte)0);
int size = BigIntegers.GetUnsignedByteLength(n);
byte[] x = new byte[size];
byte[] dVal = BigIntegers.AsUnsignedByteArray(d);
Array.Copy(dVal, 0, x, x.Length - dVal.Length, dVal.Length);
byte[] m = new byte[size];
BigInteger mInt = BitsToInt(message);
if (mInt.CompareTo(n) >= 0)
{
mInt = mInt.Subtract(n);
}
byte[] mVal = BigIntegers.AsUnsignedByteArray(mInt);
Array.Copy(mVal, 0, m, m.Length - mVal.Length, mVal.Length);
hMac.Init(new KeyParameter(K));
hMac.BlockUpdate(V, 0, V.Length);
hMac.Update((byte)0x00);
hMac.BlockUpdate(x, 0, x.Length);
hMac.BlockUpdate(m, 0, m.Length);
hMac.DoFinal(K, 0);
hMac.Init(new KeyParameter(K));
hMac.BlockUpdate(V, 0, V.Length);
hMac.DoFinal(V, 0);
hMac.BlockUpdate(V, 0, V.Length);
hMac.Update((byte)0x01);
hMac.BlockUpdate(x, 0, x.Length);
hMac.BlockUpdate(m, 0, m.Length);
hMac.DoFinal(K, 0);
hMac.Init(new KeyParameter(K));
hMac.BlockUpdate(V, 0, V.Length);
hMac.DoFinal(V, 0);
}
/**
* generate a signature for the loaded message using the key we were
* initialised with.
*/
public virtual byte[] GenerateSignature()
{
CreateSignatureBlock();
BigInteger t = new BigInteger(1, cipher.ProcessBlock(block, 0, block.Length));
ClearBlock(block);
t = t.Min(kParam.Modulus.Subtract(t));
int size = BigIntegers.GetUnsignedByteLength(kParam.Modulus);
return(BigIntegers.AsUnsignedByteArray(size, t));
}
public virtual BigInteger[] Decode(BigInteger n, byte[] encoding)
{
int valueLength = BigIntegers.GetUnsignedByteLength(n);
if (encoding.Length != valueLength * 2)
{
throw new ArgumentException("Encoding has incorrect length", "encoding");
}
return(new BigInteger[] {
DecodeValue(n, encoding, 0, valueLength),
DecodeValue(n, encoding, valueLength, valueLength),
});
}
public virtual BigInteger NextK()
{
byte[] t = new byte[BigIntegers.GetUnsignedByteLength(n)];
for (;;)
{
int tOff = 0;
while (tOff < t.Length)
{
hMac.BlockUpdate(V, 0, V.Length);
hMac.DoFinal(V, 0);
int len = System.Math.Min(t.Length - tOff, V.Length);
Array.Copy(V, 0, t, tOff, len);
tOff += len;
}
BigInteger k = BitsToInt(t);
if (k.SignValue > 0 && k.CompareTo(n) < 0)
{
return(k);
}
hMac.BlockUpdate(V, 0, V.Length);
hMac.Update((byte)0x00);
hMac.DoFinal(K, 0);
hMac.Init(new KeyParameter(K));
hMac.BlockUpdate(V, 0, V.Length);
hMac.DoFinal(V, 0);
}
}
