ISO9797Alg3Mac
using Org.BouncyCastle.Crypto.Engines;
using Org.BouncyCastle.Crypto.Modes;
using Org.BouncyCastle.Crypto.Paddings;
using Org.BouncyCastle.Crypto.Parameters;
using System;
namespace Org.BouncyCastle.Crypto.Macs
{
public class ISO9797Alg3Mac : IMac
{
private byte[] mac;
private byte[] buf;
private int bufOff;
private IBlockCipher cipher;
private IBlockCipherPadding padding;
private int macSize;
private KeyParameter lastKey2;
private KeyParameter lastKey3;
public string AlgorithmName => "ISO9797Alg3";
public ISO9797Alg3Mac(IBlockCipher cipher)
: this(cipher, cipher.GetBlockSize() * 8, null)
{
}
public ISO9797Alg3Mac(IBlockCipher cipher, IBlockCipherPadding padding)
: this(cipher, cipher.GetBlockSize() * 8, padding)
{
}
public ISO9797Alg3Mac(IBlockCipher cipher, int macSizeInBits)
: this(cipher, macSizeInBits, null)
{
}
public ISO9797Alg3Mac(IBlockCipher cipher, int macSizeInBits, IBlockCipherPadding padding)
{
if (macSizeInBits % 8 != 0)
throw new ArgumentException("MAC size must be multiple of 8");
if (!(cipher is DesEngine))
throw new ArgumentException("cipher must be instance of DesEngine");
this.cipher = new CbcBlockCipher(cipher);
this.padding = padding;
macSize = macSizeInBits / 8;
mac = new byte[cipher.GetBlockSize()];
buf = new byte[cipher.GetBlockSize()];
bufOff = 0;
}
public void Init(ICipherParameters parameters)
{
Reset();
if (!(parameters is KeyParameter) && !(parameters is ParametersWithIV))
throw new ArgumentException("parameters must be an instance of KeyParameter or ParametersWithIV");
KeyParameter keyParameter = (!(parameters is KeyParameter)) ? ((KeyParameter)((ParametersWithIV)parameters).Parameters) : ((KeyParameter)parameters);
byte[] key = keyParameter.GetKey();
KeyParameter parameters2;
if (key.Length == 16) {
parameters2 = new KeyParameter(key, 0, 8);
lastKey2 = new KeyParameter(key, 8, 8);
lastKey3 = parameters2;
} else {
if (key.Length != 24)
throw new ArgumentException("Key must be either 112 or 168 bit long");
parameters2 = new KeyParameter(key, 0, 8);
lastKey2 = new KeyParameter(key, 8, 8);
lastKey3 = new KeyParameter(key, 16, 8);
}
if (parameters is ParametersWithIV)
cipher.Init(true, new ParametersWithIV(parameters2, ((ParametersWithIV)parameters).GetIV()));
else
cipher.Init(true, parameters2);
}
public int GetMacSize()
{
return macSize;
}
public void Update(byte input)
{
if (bufOff == buf.Length) {
cipher.ProcessBlock(buf, 0, mac, 0);
bufOff = 0;
}
buf[bufOff++] = input;
}
public void BlockUpdate(byte[] input, int inOff, int len)
{
if (len < 0)
throw new ArgumentException("Can't have a negative input length!");
int blockSize = cipher.GetBlockSize();
int num = 0;
int num2 = blockSize - bufOff;
if (len > num2) {
Array.Copy(input, inOff, buf, bufOff, num2);
num += cipher.ProcessBlock(buf, 0, mac, 0);
bufOff = 0;
len -= num2;
inOff += num2;
while (len > blockSize) {
num += cipher.ProcessBlock(input, inOff, mac, 0);
len -= blockSize;
inOff += blockSize;
}
}
Array.Copy(input, inOff, buf, bufOff, len);
bufOff += len;
}
public int DoFinal(byte[] output, int outOff)
{
int blockSize = cipher.GetBlockSize();
if (padding == null) {
while (bufOff < blockSize) {
buf[bufOff++] = 0;
}
} else {
if (bufOff == blockSize) {
cipher.ProcessBlock(buf, 0, mac, 0);
bufOff = 0;
}
padding.AddPadding(buf, bufOff);
}
cipher.ProcessBlock(buf, 0, mac, 0);
DesEngine desEngine = new DesEngine();
desEngine.Init(false, lastKey2);
desEngine.ProcessBlock(mac, 0, mac, 0);
desEngine.Init(true, lastKey3);
desEngine.ProcessBlock(mac, 0, mac, 0);
Array.Copy(mac, 0, output, outOff, macSize);
Reset();
return macSize;
}
public void Reset()
{
Array.Clear(buf, 0, buf.Length);
bufOff = 0;
}
}
}