public static PrivateKeyInfo createPrivateKeyInfo(AsymmetricKeyParameter key)
{
/*
* Process DH private key.
* The value for L was set to zero implicitly.
* This is the same action as found in JCEDHPrivateKey getEncoded method.
*/
if (key is ElGamalPrivateKeyParameters)
{
ElGamalPrivateKeyParameters _key = (ElGamalPrivateKeyParameters)key;
PrivateKeyInfo info =
new PrivateKeyInfo(
new AlgorithmIdentifier(
OIWObjectIdentifiers.elGamalAlgorithm,
new ElGamalParameter(
_key.getParameters().getP(),
_key.getParameters().getG()).toASN1Object()), new DERInteger(_key.getX()));
return(info);
}
if (key is DSAPrivateKeyParameters)
{
DSAPrivateKeyParameters _key = (DSAPrivateKeyParameters)key;
PrivateKeyInfo info =
new PrivateKeyInfo(
new AlgorithmIdentifier(
X9ObjectIdentifiers.id_dsa,
new DSAParameter(
_key.getParameters().getP(),
_key.getParameters().getQ(),
_key.getParameters().getG()).toASN1Object()), new DERInteger(_key.getX()));
return(info);
}
if (key is DHPrivateKeyParameters)
{
DHPrivateKeyParameters _key = (DHPrivateKeyParameters)key;
PrivateKeyInfo info = new PrivateKeyInfo(
new AlgorithmIdentifier(
PKCSObjectIdentifiers.dhKeyAgreement, new DHParameter(
_key.getParameters().getP(),
_key.getParameters().getG(),
0
).toASN1Object()
)
, new DERInteger(_key.getX()));
return(info);
}
if (key is RSAPrivateCrtKeyParameters)
{
RSAPrivateCrtKeyParameters _key = (RSAPrivateCrtKeyParameters)key;
PrivateKeyInfo info = new PrivateKeyInfo(
new AlgorithmIdentifier(
PKCSObjectIdentifiers.rsaEncryption, new DERNull()),
new RSAPrivateKeyStructure(
_key.getModulus(),
_key.getPublicExponent(),
_key.getExponent(),
_key.getP(),
_key.getQ(),
_key.getDP(),
_key.getDQ(),
_key.getQInv()).toASN1Object());
return(info);
}
if (key is ECPrivateKeyParameters)
{
ECPrivateKeyParameters _key = (ECPrivateKeyParameters)key;
X9ECParameters ecP = new X9ECParameters(
_key.getParameters().getCurve(),
_key.getParameters().getG(),
_key.getParameters().getN(),
_key.getParameters().getH(),
_key.getParameters().getSeed());
X962Parameters x962 = new X962Parameters(ecP);
PrivateKeyInfo info = new PrivateKeyInfo(
new AlgorithmIdentifier(X9ObjectIdentifiers.id_ecPublicKey, x962.toASN1Object()),
new ECPrivateKeyStructure(_key.getD()).toASN1Object());
return(info);
}
throw (new Exception("Class provided is not convertable:" + key.GetType()));
}
/**
* Process a single block using the basic ElGamal algorithm.
*
* @param in the input array.
* @param inOff the offset into the input buffer where the data starts.
* @param inLen the length of the data to be processed.
* @return the result of the ElGamal process.
* @exception DataLengthException the input block is too large.
*/
public byte[] processBlock(
byte[] inBytes,
int inOff,
int inLen)
{
if (inLen > (getInputBlockSize() + 1))
{
throw new DataLengthException("input too large for ElGamal cipher.\n");
}
else if (inLen == (getInputBlockSize() + 1) && (inBytes[inOff] & 0x80) != 0)
{
throw new DataLengthException("input too large for ElGamal cipher.\n");
}
byte[] block;
if (inOff != 0 || inLen != inBytes.Length)
{
block = new byte[inLen];
Array.Copy(inBytes, inOff, block, 0, inLen);
}
else
{
block = inBytes;
}
BigInteger input = new BigInteger(1, block);
BigInteger g = key.getParameters().getG();
BigInteger p = key.getParameters().getP();
if (typeof(ElGamalPrivateKeyParameters).IsInstanceOfType(key))
{
byte[] in1 = new byte[inBytes.Length / 2];
byte[] in2 = new byte[inBytes.Length / 2];
Array.Copy(inBytes, 0, in1, 0, in1.Length);
Array.Copy(inBytes, in1.Length, in2, 0, in2.Length);
BigInteger gamma = new BigInteger(1, in1);
BigInteger phi = new BigInteger(1, in2);
ElGamalPrivateKeyParameters priv = (ElGamalPrivateKeyParameters)key;
BigInteger m = gamma.modPow(p.subtract(ONE).subtract(priv.getX()), p).multiply(phi).mod(p);
byte[] outBytes = m.toByteArray();
if (outBytes[0] != 0)
{
return(outBytes);
}
else
{
byte[] output = new byte[outBytes.Length - 1];
Array.Copy(outBytes, 1, output, 0, output.Length);
return(output);
}
}
else
{
ElGamalPublicKeyParameters pub = (ElGamalPublicKeyParameters)key;
BigInteger k = new BigInteger(p.bitLength(), random);
while (k.Equals(ZERO) || (k.compareTo(p.subtract(TWO)) > 0))
{
k = new BigInteger(p.bitLength(), random);
}
BigInteger gamma = g.modPow(k, p);
BigInteger phi = input.multiply(pub.getY().modPow(k, p)).mod(p);
byte[] out1 = gamma.toByteArray();
byte[] out2 = phi.toByteArray();
byte[] output = new byte[this.getOutputBlockSize()];
if (out1[0] == 0)
{
Array.Copy(out1, 1, output, output.Length / 2 - (out1.Length - 1), out1.Length - 1);
}
else
{
Array.Copy(out1, 0, output, output.Length / 2 - out1.Length, out1.Length);
}
if (out2[0] == 0)
{
Array.Copy(out2, 1, output, output.Length - (out2.Length - 1), out2.Length - 1);
}
else
{
Array.Copy(out2, 0, output, output.Length - out2.Length, out2.Length);
}
return(output);
}
}
