/// <summary>
/// Generate key pair.
/// </summary>
/// <returns></returns>
public override AsymmetricCipherKeyPair GenerateKeyPair()
{
ElGamalParametersGenerator generator2 = new ElGamalParametersGenerator();
generator2.Init(_keySize, _certainty, Common.ThreadSecureRandom.Value);
ElGamalParameters parameters2 = generator2.GenerateParameters();
KeyGenerationParameters parameters = new ElGamalKeyGenerationParameters(Common.ThreadSecureRandom.Value, parameters2);
IAsymmetricCipherKeyPairGenerator generator = new ElGamalKeyPairGenerator();
generator.Init(parameters);
return(generator.GenerateKeyPair());
}
/**
* this test is can take quiet a while
*
* @param size size of key in bits.
*/
private void doTestGeneration(
int size)
{
ElGamalParametersGenerator pGen = new ElGamalParametersGenerator();
pGen.Init(size, 10, new SecureRandom());
ElGamalParameters elParams = pGen.GenerateParameters();
if (elParams.L != 0)
{
Fail("ElGamalParametersGenerator failed to set L to 0 in generated ElGamalParameters");
}
ElGamalKeyGenerationParameters ekgParams = new ElGamalKeyGenerationParameters(new SecureRandom(), elParams);
ElGamalKeyPairGenerator kpGen = new ElGamalKeyPairGenerator();
kpGen.Init(ekgParams);
//
// generate first pair
//
AsymmetricCipherKeyPair pair = kpGen.GenerateKeyPair();
ElGamalPublicKeyParameters pu = (ElGamalPublicKeyParameters)pair.Public;
ElGamalPrivateKeyParameters pv = (ElGamalPrivateKeyParameters)pair.Private;
ElGamalEngine e = new ElGamalEngine();
e.Init(true, new ParametersWithRandom(pu, new SecureRandom()));
byte[] message = Hex.Decode("5468697320697320612074657374");
byte[] pText = message;
byte[] cText = e.ProcessBlock(pText, 0, pText.Length);
e.Init(false, pv);
pText = e.ProcessBlock(cText, 0, cText.Length);
if (!Arrays.AreEqual(message, pText))
{
Fail("generation test failed");
}
}
public AsymmetricCipherKeyPair GenerateElGamalKeyPair(int keySize, BigInteger prime = null, BigInteger generator = null)
{
ElGamalParameters elGamalParameters;
if (prime != null && generator != null)
{
elGamalParameters = new ElGamalParameters(prime, generator);
}
else
{
var elGamalParameterGenerator = new ElGamalParametersGenerator();
elGamalParameterGenerator.Init(keySize, 64, secureRandom.Generator);
elGamalParameters = elGamalParameterGenerator.GenerateParameters();
}
var keyGenerationParameters = new ElGamalKeyGenerationParameters(secureRandom.Generator, elGamalParameters);
var keyPairGenerator = new ElGamalKeyPairGenerator();
keyPairGenerator.Init(keyGenerationParameters);
return(keyPairGenerator.GenerateKeyPair());
}
public void TestElGamal()
{
BigInteger g512 = new BigInteger("153d5d6172adb43045b68ae8e1de1070b6137005686d29d3d73a7749199681ee5b212c9b96bfdcfa5b20cd5e3fd2044895d609cf9b410b7a0f12ca1cb9a428cc", 16);
BigInteger p512 = new BigInteger("9494fec095f3b85ee286542b3836fc81a5dd0a0349b4c239dd38744d488cf8e31db8bcb7d33b41abb9e5a33cca9144b1cef332c94bf0573bf047a3aca98cdf3b", 16);
ElGamalParameters dhParams = new ElGamalParameters(p512, g512);
ElGamalKeyGenerationParameters parameters = new ElGamalKeyGenerationParameters(new SecureRandom(), dhParams); ElGamalKeyPairGenerator kpGen = new ElGamalKeyPairGenerator();
kpGen.Init(parameters);
AsymmetricCipherKeyPair pair = kpGen.GenerateKeyPair();
ElGamalPublicKeyParameters pu1 = (ElGamalPublicKeyParameters)pair.Public;
ElGamalPrivateKeyParameters pv1 = (ElGamalPrivateKeyParameters)pair.Private;
ElGamalPublicKeyParameters pu2 = new ElGamalPublicKeyParameters(pu1.Y, pu1.Parameters);
ElGamalPrivateKeyParameters pv2 = new ElGamalPrivateKeyParameters(pv1.X, pv1.Parameters);
ElGamalPublicKeyParameters pu3 = new ElGamalPublicKeyParameters(pv1.X, pu1.Parameters);
ElGamalPrivateKeyParameters pv3 = new ElGamalPrivateKeyParameters(pu1.Y, pu1.Parameters);
doTest(pu1, pu2, pu3);
doTest(pv1, pv2, pv3);
ElGamalParameters pr1 = pu1.Parameters;
ElGamalParameters pr2 = new ElGamalParameters(pr1.P, pr1.G);
ElGamalParameters pr3 = new ElGamalParameters(pr1.G, pr1.P);
doTest(pr1, pr2, pr3);
pu2 = new ElGamalPublicKeyParameters(pu1.Y, pr2);
pv2 = new ElGamalPrivateKeyParameters(pv1.X, pr2);
doTest(pu1, pu2, pu3);
doTest(pv1, pv2, pv3);
ElGamalTestKeyParameters k1 = new ElGamalTestKeyParameters(false, null);
ElGamalTestKeyParameters k2 = new ElGamalTestKeyParameters(false, null);
ElGamalTestKeyParameters k3 = new ElGamalTestKeyParameters(false, pu1.Parameters);
doTest(k1, k2, k3);
}
private void doTestEnc(
int size,
int privateValueSize,
BigInteger g,
BigInteger p)
{
ElGamalParameters dhParams = new ElGamalParameters(p, g, privateValueSize);
ElGamalKeyGenerationParameters ekgParams = new ElGamalKeyGenerationParameters(new SecureRandom(), dhParams);
ElGamalKeyPairGenerator kpGen = new ElGamalKeyPairGenerator();
kpGen.Init(ekgParams);
//
// generate pair
//
AsymmetricCipherKeyPair pair = kpGen.GenerateKeyPair();
ElGamalPublicKeyParameters pu = (ElGamalPublicKeyParameters)pair.Public;
ElGamalPrivateKeyParameters pv = (ElGamalPrivateKeyParameters)pair.Private;
checkKeySize(privateValueSize, pv);
ElGamalEngine e = new ElGamalEngine();
e.Init(true, pu);
if (e.GetOutputBlockSize() != size / 4)
{
Fail(size + " GetOutputBlockSize() on encryption failed.");
}
byte[] message = Hex.Decode("5468697320697320612074657374");
byte[] pText = message;
byte[] cText = e.ProcessBlock(pText, 0, pText.Length);
e.Init(false, pv);
if (e.GetOutputBlockSize() != (size / 8) - 1)
{
Fail(size + " GetOutputBlockSize() on decryption failed.");
}
pText = e.ProcessBlock(cText, 0, cText.Length);
if (!Arrays.AreEqual(message, pText))
{
Fail(size + " bit test failed");
}
e.Init(true, pu);
byte[] bytes = new byte[e.GetInputBlockSize() + 2];
try
{
e.ProcessBlock(bytes, 0, bytes.Length);
Fail("out of range block not detected");
}
catch (DataLengthException)
{
// expected
}
try
{
bytes[0] = (byte)0xff;
e.ProcessBlock(bytes, 0, bytes.Length - 1);
Fail("out of range block not detected");
}
catch (DataLengthException)
{
// expected
}
try
{
bytes[0] = (byte)0x7f;
e.ProcessBlock(bytes, 0, bytes.Length - 1);
}
catch (DataLengthException)
{
Fail("in range block failed");
}
}
