static IBlockCipher Setup(IBlockCipher algo, string mode, bool encryption, byte[] key, byte[] iv)
{
if (mode == "ECB")
{
algo.Init(encryption, new KeyParameter(key));
return(algo);
}
IBlockCipher cipher = null;
if (mode == "CBC")
{
cipher = new Org.BouncyCastle.Crypto.Modes.CbcBlockCipher(algo);
}
if (mode == "CFB")
{
cipher = new Org.BouncyCastle.Crypto.Modes.CfbBlockCipher(algo, iv.Length << 3);
}
if (mode == "OFB")
{
cipher = new Org.BouncyCastle.Crypto.Modes.OfbBlockCipher(algo, iv.Length);
}
if (cipher != null)
{
cipher.Init(encryption, new ParametersWithIV(new KeyParameter(key), iv));
return(cipher);
}
throw new ArgumentException();
}
public byte[] ofbDecoding(byte[] key, byte[] message, byte[] iv)
{
Crypto.Engines.AesEngine engine = new Crypto.Engines.AesEngine();
Crypto.Modes.OfbBlockCipher blockCipher = new Crypto.Modes.OfbBlockCipher(engine, 128);
Crypto.Paddings.PaddedBufferedBlockCipher cipher = new Crypto.Paddings.PaddedBufferedBlockCipher(blockCipher);
Crypto.Parameters.KeyParameter keyParam = new Crypto.Parameters.KeyParameter(key);
Crypto.Parameters.ParametersWithIV keyParamWithIV = new Crypto.Parameters.ParametersWithIV(keyParam, iv);
cipher.Init(false, keyParamWithIV);
byte[] comparisonBytes = new byte[cipher.GetOutputSize(message.Length)];
int length = cipher.ProcessBytes(message, comparisonBytes, 0);
cipher.DoFinal(comparisonBytes, length);
return(comparisonBytes);
}
static IBlockCipher Setup (IBlockCipher algo, string mode, bool encryption, byte[] key, byte[] iv)
{
if (mode == "ECB") {
algo.Init (encryption, new KeyParameter (key));
return algo;
}
IBlockCipher cipher = null;
if (mode == "CBC") cipher = new Org.BouncyCastle.Crypto.Modes.CbcBlockCipher (algo);
if (mode == "CFB") cipher = new Org.BouncyCastle.Crypto.Modes.CfbBlockCipher (algo, iv.Length << 3);
if (mode == "OFB") cipher = new Org.BouncyCastle.Crypto.Modes.OfbBlockCipher (algo, iv.Length);
if (cipher != null) {
cipher.Init (encryption, new ParametersWithIV (new KeyParameter (key), iv));
return cipher;
}
throw new ArgumentException ();
}
