private static IAsymmetricBlockCipher createCipher(bool forEncryption, IAsymmetricKey key, IParameters<Algorithm> parameters, SecureRandom random)
{
IAsymmetricBlockCipher engine = new ElGamalEngine();
ICipherParameters lwParams;
if (key is AsymmetricDHPublicKey)
{
AsymmetricDHPublicKey k = (AsymmetricDHPublicKey)key;
lwParams = new ElGamalPublicKeyParameters(k.Y, new DHParameters(k.DomainParameters.P, k.DomainParameters.G, k.DomainParameters.Q, k.DomainParameters.L));
}
else
{
AsymmetricDHPrivateKey k = (AsymmetricDHPrivateKey)key;
lwParams = new ElGamalPrivateKeyParameters(k.X, new DHParameters(k.DomainParameters.P, k.DomainParameters.G, k.DomainParameters.Q, k.DomainParameters.L));
}
if (parameters.Algorithm.Equals(WrapPkcs1v15.Algorithm))
{
engine = new Pkcs1Encoding(engine);
}
else if (parameters.Algorithm.Equals(WrapOaep.Algorithm))
{
OaepWrapParameters oeapParams = (OaepWrapParameters)parameters;
engine = new OaepEncoding(engine, FipsShs.CreateDigest(oeapParams.DigestAlgorithm), FipsShs.CreateDigest(oeapParams.MgfDigestAlgorithm), oeapParams.GetEncodingParams());
}
if (random != null)
{
lwParams = new ParametersWithRandom(lwParams, random);
}
engine.Init(forEncryption, lwParams);
return engine;
}
public KeyGenerationParameters For(OaepWrapParameters oaepUsage)
{
return(new KeyGenerationParameters(oaepUsage, this));
}