126 lines
2.9 KiB
C#
126 lines
2.9 KiB
C#
using System;
|
|
using Org.BouncyCastle.Crypto.Parameters;
|
|
|
|
namespace Org.BouncyCastle.Crypto.Modes;
|
|
|
|
public class CbcBlockCipher : IBlockCipher
|
|
{
|
|
private byte[] IV;
|
|
|
|
private byte[] cbcV;
|
|
|
|
private byte[] cbcNextV;
|
|
|
|
private int blockSize;
|
|
|
|
private IBlockCipher cipher;
|
|
|
|
private bool encrypting;
|
|
|
|
public string AlgorithmName => cipher.AlgorithmName + "/CBC";
|
|
|
|
public bool IsPartialBlockOkay => false;
|
|
|
|
public CbcBlockCipher(IBlockCipher cipher)
|
|
{
|
|
this.cipher = cipher;
|
|
blockSize = cipher.GetBlockSize();
|
|
IV = new byte[blockSize];
|
|
cbcV = new byte[blockSize];
|
|
cbcNextV = new byte[blockSize];
|
|
}
|
|
|
|
public IBlockCipher GetUnderlyingCipher()
|
|
{
|
|
return cipher;
|
|
}
|
|
|
|
public void Init(bool forEncryption, ICipherParameters parameters)
|
|
{
|
|
bool flag = encrypting;
|
|
encrypting = forEncryption;
|
|
if (parameters is ParametersWithIV)
|
|
{
|
|
ParametersWithIV parametersWithIV = (ParametersWithIV)parameters;
|
|
byte[] iV = parametersWithIV.GetIV();
|
|
if (iV.Length != blockSize)
|
|
{
|
|
throw new ArgumentException("initialisation vector must be the same length as block size");
|
|
}
|
|
Array.Copy(iV, 0, IV, 0, iV.Length);
|
|
parameters = parametersWithIV.Parameters;
|
|
}
|
|
Reset();
|
|
if (parameters != null)
|
|
{
|
|
cipher.Init(encrypting, parameters);
|
|
}
|
|
else if (flag != encrypting)
|
|
{
|
|
throw new ArgumentException("cannot change encrypting state without providing key.");
|
|
}
|
|
}
|
|
|
|
public int GetBlockSize()
|
|
{
|
|
return cipher.GetBlockSize();
|
|
}
|
|
|
|
public int ProcessBlock(byte[] input, int inOff, byte[] output, int outOff)
|
|
{
|
|
if (!encrypting)
|
|
{
|
|
return DecryptBlock(input, inOff, output, outOff);
|
|
}
|
|
return EncryptBlock(input, inOff, output, outOff);
|
|
}
|
|
|
|
public void Reset()
|
|
{
|
|
Array.Copy(IV, 0, cbcV, 0, IV.Length);
|
|
Array.Clear(cbcNextV, 0, cbcNextV.Length);
|
|
cipher.Reset();
|
|
}
|
|
|
|
private int EncryptBlock(byte[] input, int inOff, byte[] outBytes, int outOff)
|
|
{
|
|
if (inOff + blockSize > input.Length)
|
|
{
|
|
throw new DataLengthException("input buffer too short");
|
|
}
|
|
for (int i = 0; i < blockSize; i++)
|
|
{
|
|
byte[] array2;
|
|
byte[] array = (array2 = cbcV);
|
|
int num = i;
|
|
nint num2 = num;
|
|
array[num] = (byte)(array2[num2] ^ input[inOff + i]);
|
|
}
|
|
int result = cipher.ProcessBlock(cbcV, 0, outBytes, outOff);
|
|
Array.Copy(outBytes, outOff, cbcV, 0, cbcV.Length);
|
|
return result;
|
|
}
|
|
|
|
private int DecryptBlock(byte[] input, int inOff, byte[] outBytes, int outOff)
|
|
{
|
|
if (inOff + blockSize > input.Length)
|
|
{
|
|
throw new DataLengthException("input buffer too short");
|
|
}
|
|
Array.Copy(input, inOff, cbcNextV, 0, blockSize);
|
|
int result = cipher.ProcessBlock(input, inOff, outBytes, outOff);
|
|
for (int i = 0; i < blockSize; i++)
|
|
{
|
|
byte[] array2;
|
|
byte[] array = (array2 = outBytes);
|
|
int num = outOff + i;
|
|
nint num2 = num;
|
|
array[num] = (byte)(array2[num2] ^ cbcV[i]);
|
|
}
|
|
byte[] array3 = cbcV;
|
|
cbcV = cbcNextV;
|
|
cbcNextV = array3;
|
|
return result;
|
|
}
|
|
}
|