private byte[] RecoverSessionData(PgpPrivateKey privKey)
{
byte[][] encSessionKey = keyData.GetEncSessionKey();
if (keyData.Algorithm == PublicKeyAlgorithmTag.EC)
{
ECDHPublicBcpgKey eCDHPublicBcpgKey = (ECDHPublicBcpgKey)privKey.PublicKeyPacket.Key;
X9ECParameters x9ECParameters = ECKeyPairGenerator.FindECCurveByOid(eCDHPublicBcpgKey.CurveOid);
byte[] array = encSessionKey[0];
int num = (((array[0] & 0xFF) << 8) + (array[1] & 0xFF) + 7) / 8;
byte[] array2 = new byte[num];
Array.Copy(array, 2, array2, 0, num);
byte[] array3 = new byte[array[num + 2]];
Array.Copy(array, 2 + num + 1, array3, 0, array3.Length);
ECPoint eCPoint = x9ECParameters.Curve.DecodePoint(array2);
ECPrivateKeyParameters eCPrivateKeyParameters = (ECPrivateKeyParameters)privKey.Key;
ECPoint s = eCPoint.Multiply(eCPrivateKeyParameters.D).Normalize();
KeyParameter parameters = new KeyParameter(Rfc6637Utilities.CreateKey(privKey.PublicKeyPacket, s));
IWrapper wrapper = PgpUtilities.CreateWrapper(eCDHPublicBcpgKey.SymmetricKeyAlgorithm);
wrapper.Init(forWrapping: false, parameters);
return(PgpPad.UnpadSessionData(wrapper.Unwrap(array3, 0, array3.Length)));
}
IBufferedCipher keyCipher = GetKeyCipher(keyData.Algorithm);
try
{
keyCipher.Init(forEncryption: false, privKey.Key);
}
catch (InvalidKeyException exception)
{
throw new PgpException("error setting asymmetric cipher", exception);
}
if (keyData.Algorithm == PublicKeyAlgorithmTag.RsaEncrypt || keyData.Algorithm == PublicKeyAlgorithmTag.RsaGeneral)
{
byte[] array4 = encSessionKey[0];
keyCipher.ProcessBytes(array4, 2, array4.Length - 2);
}
else
{
ElGamalPrivateKeyParameters elGamalPrivateKeyParameters = (ElGamalPrivateKeyParameters)privKey.Key;
int size = (elGamalPrivateKeyParameters.Parameters.P.BitLength + 7) / 8;
ProcessEncodedMpi(keyCipher, size, encSessionKey[0]);
ProcessEncodedMpi(keyCipher, size, encSessionKey[1]);
}
try
{
return(keyCipher.DoFinal());
}
catch (Exception exception2)
{
throw new PgpException("exception decrypting secret key", exception2);
}
}
private byte[] EncryptSessionInfo(byte[] sessionInfo, SecureRandom random)
{
if (pubKey.Algorithm != PublicKeyAlgorithmTag.EC)
{
IBufferedCipher cipher;
switch (pubKey.Algorithm)
{
case PublicKeyAlgorithmTag.RsaGeneral:
case PublicKeyAlgorithmTag.RsaEncrypt:
cipher = CipherUtilities.GetCipher("RSA//PKCS1Padding");
break;
case PublicKeyAlgorithmTag.ElGamalEncrypt:
case PublicKeyAlgorithmTag.ElGamalGeneral:
cipher = CipherUtilities.GetCipher("ElGamal/ECB/PKCS1Padding");
break;
case PublicKeyAlgorithmTag.Dsa:
throw new PgpException("Can't use DSA for encryption.");
case PublicKeyAlgorithmTag.ECDsa:
throw new PgpException("Can't use ECDSA for encryption.");
default:
throw new PgpException("unknown asymmetric algorithm: " + pubKey.Algorithm);
}
AsymmetricKeyParameter key = pubKey.GetKey();
cipher.Init(forEncryption: true, new ParametersWithRandom(key, random));
return(cipher.DoFinal(sessionInfo));
}
ECDHPublicBcpgKey eCDHPublicBcpgKey = (ECDHPublicBcpgKey)pubKey.PublicKeyPacket.Key;
IAsymmetricCipherKeyPairGenerator keyPairGenerator = GeneratorUtilities.GetKeyPairGenerator("ECDH");
keyPairGenerator.Init(new ECKeyGenerationParameters(eCDHPublicBcpgKey.CurveOid, random));
AsymmetricCipherKeyPair asymmetricCipherKeyPair = keyPairGenerator.GenerateKeyPair();
ECPrivateKeyParameters eCPrivateKeyParameters = (ECPrivateKeyParameters)asymmetricCipherKeyPair.Private;
ECPublicKeyParameters eCPublicKeyParameters = (ECPublicKeyParameters)asymmetricCipherKeyPair.Public;
ECPublicKeyParameters eCPublicKeyParameters2 = (ECPublicKeyParameters)pubKey.GetKey();
ECPoint s = eCPublicKeyParameters2.Q.Multiply(eCPrivateKeyParameters.D).Normalize();
KeyParameter parameters = new KeyParameter(Rfc6637Utilities.CreateKey(pubKey.PublicKeyPacket, s));
IWrapper wrapper = PgpUtilities.CreateWrapper(eCDHPublicBcpgKey.SymmetricKeyAlgorithm);
wrapper.Init(forWrapping: true, new ParametersWithRandom(parameters, random));
byte[] array = PgpPad.PadSessionData(sessionInfo);
byte[] array2 = wrapper.Wrap(array, 0, array.Length);
byte[] encoded = new MPInteger(new BigInteger(1, eCPublicKeyParameters.Q.GetEncoded(compressed: false))).GetEncoded();
byte[] array3 = new byte[encoded.Length + 1 + array2.Length];
Array.Copy(encoded, 0, array3, 0, encoded.Length);
array3[encoded.Length] = (byte)array2.Length;
Array.Copy(array2, 0, array3, encoded.Length + 1, array2.Length);
return(array3);
}