CbcBlockCipherMac
using Org.BouncyCastle.Crypto.Modes;
using Org.BouncyCastle.Crypto.Paddings;
using System;
namespace Org.BouncyCastle.Crypto.Macs
{
public class CbcBlockCipherMac : IMac
{
private byte[] buf;
private int bufOff;
private IBlockCipherMode m_cipherMode;
private IBlockCipherPadding padding;
private int macSize;
public string AlgorithmName => m_cipherMode.AlgorithmName;
public CbcBlockCipherMac(IBlockCipher cipher)
: this(cipher, cipher.GetBlockSize() * 8 / 2, null)
{
}
public CbcBlockCipherMac(IBlockCipher cipher, IBlockCipherPadding padding)
: this(cipher, cipher.GetBlockSize() * 8 / 2, padding)
{
}
public CbcBlockCipherMac(IBlockCipher cipher, int macSizeInBits)
: this(cipher, macSizeInBits, null)
{
}
public CbcBlockCipherMac(IBlockCipher cipher, int macSizeInBits, IBlockCipherPadding padding)
{
if (macSizeInBits % 8 != 0)
throw new ArgumentException("MAC size must be multiple of 8");
m_cipherMode = new CbcBlockCipher(cipher);
this.padding = padding;
macSize = macSizeInBits / 8;
buf = new byte[cipher.GetBlockSize()];
bufOff = 0;
}
public void Init(ICipherParameters parameters)
{
Reset();
m_cipherMode.Init(true, parameters);
}
public int GetMacSize()
{
return macSize;
}
public void Update(byte input)
{
if (bufOff == buf.Length) {
m_cipherMode.ProcessBlock(buf, 0, 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!");
BlockUpdate(input.AsSpan(inOff, len));
}
public void BlockUpdate(ReadOnlySpan<byte> input)
{
int blockSize = m_cipherMode.GetBlockSize();
int num = blockSize - bufOff;
if (input.Length > num) {
input.Slice(0, num).CopyTo(buf.AsSpan(bufOff));
m_cipherMode.ProcessBlock(buf, buf);
bufOff = 0;
int num2 = num;
input = input.Slice(num2, input.Length - num2);
while (input.Length > blockSize) {
m_cipherMode.ProcessBlock(input, buf);
num2 = blockSize;
input = input.Slice(num2, input.Length - num2);
}
}
input.CopyTo(buf.AsSpan(bufOff));
bufOff += input.Length;
}
public int DoFinal(byte[] output, int outOff)
{
return DoFinal(output.AsSpan(outOff));
}
public int DoFinal(Span<byte> output)
{
int blockSize = m_cipherMode.GetBlockSize();
if (padding == null) {
while (bufOff < blockSize) {
buf[bufOff++] = 0;
}
} else {
if (bufOff == blockSize) {
m_cipherMode.ProcessBlock(buf, buf);
bufOff = 0;
}
padding.AddPadding(buf, bufOff);
}
m_cipherMode.ProcessBlock(buf, buf);
buf.AsSpan(0, macSize).CopyTo(output);
Reset();
return macSize;
}
public void Reset()
{
Array.Clear(buf, 0, buf.Length);
bufOff = 0;
m_cipherMode.Reset();
}
}
}