Dstu7624Mac
using Org.BouncyCastle.Crypto.Engines;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Utilities;
using System;
namespace Org.BouncyCastle.Crypto.Macs
{
public class Dstu7624Mac : IMac
{
private int macSize;
private Dstu7624Engine engine;
private int blockSize;
private byte[] c;
private byte[] cTemp;
private byte[] kDelta;
private byte[] buf;
private int bufOff;
public string AlgorithmName => "Dstu7624Mac";
public Dstu7624Mac(int blockSizeBits, int q)
{
engine = new Dstu7624Engine(blockSizeBits);
blockSize = blockSizeBits / 8;
macSize = q / 8;
c = new byte[blockSize];
cTemp = new byte[blockSize];
kDelta = new byte[blockSize];
buf = new byte[blockSize];
}
public void Init(ICipherParameters parameters)
{
if (parameters is KeyParameter) {
engine.Init(true, (KeyParameter)parameters);
engine.ProcessBlock(kDelta, 0, kDelta, 0);
return;
}
throw new ArgumentException("invalid parameter passed to Dstu7624Mac init - " + Platform.GetTypeName(parameters));
}
public int GetMacSize()
{
return macSize;
}
public void Update(byte input)
{
if (bufOff == buf.Length) {
ProcessBlock(buf, 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 num = engine.GetBlockSize();
int num2 = num - bufOff;
if (len > num2) {
Array.Copy(input, inOff, buf, bufOff, num2);
ProcessBlock(buf, 0);
bufOff = 0;
len -= num2;
inOff += num2;
while (len > num) {
ProcessBlock(input, inOff);
len -= num;
inOff += num;
}
}
Array.Copy(input, inOff, buf, bufOff, len);
bufOff += len;
}
private void ProcessBlock(byte[] input, int inOff)
{
Xor(c, 0, input, inOff, cTemp);
engine.ProcessBlock(cTemp, 0, c, 0);
}
private void Xor(byte[] c, int cOff, byte[] input, int inOff, byte[] xorResult)
{
for (int i = 0; i < blockSize; i++) {
xorResult[i] = (byte)(c[i + cOff] ^ input[i + inOff]);
}
}
public int DoFinal(byte[] output, int outOff)
{
if (bufOff % buf.Length != 0)
throw new DataLengthException("Input must be a multiple of blocksize");
Check.OutputLength(output, outOff, macSize, "output buffer too short");
Xor(c, 0, buf, 0, cTemp);
Xor(cTemp, 0, kDelta, 0, c);
engine.ProcessBlock(c, 0, c, 0);
Array.Copy(c, 0, output, outOff, macSize);
return macSize;
}
public void Reset()
{
Arrays.Fill(c, 0);
Arrays.Fill(cTemp, 0);
Arrays.Fill(kDelta, 0);
Arrays.Fill(buf, 0);
engine.ProcessBlock(kDelta, 0, kDelta, 0);
bufOff = 0;
}
}
}