CfbBlockCipherMac
using Org.BouncyCastle.Crypto.Paddings;
using System;
namespace Org.BouncyCastle.Crypto.Macs
{
public class CfbBlockCipherMac : IMac
{
private byte[] mac;
private byte[] Buffer;
private int bufOff;
private MacCfbBlockCipher cipher;
private IBlockCipherPadding padding;
private int macSize;
public string AlgorithmName => cipher.AlgorithmName;
public CfbBlockCipherMac(IBlockCipher cipher)
: this(cipher, 8, cipher.GetBlockSize() * 8 / 2, null)
{
}
public CfbBlockCipherMac(IBlockCipher cipher, IBlockCipherPadding padding)
: this(cipher, 8, cipher.GetBlockSize() * 8 / 2, padding)
{
}
public CfbBlockCipherMac(IBlockCipher cipher, int cfbBitSize, int macSizeInBits)
: this(cipher, cfbBitSize, macSizeInBits, null)
{
}
public CfbBlockCipherMac(IBlockCipher cipher, int cfbBitSize, int macSizeInBits, IBlockCipherPadding padding)
{
if (macSizeInBits % 8 != 0)
throw new ArgumentException("MAC size must be multiple of 8");
mac = new byte[cipher.GetBlockSize()];
this.cipher = new MacCfbBlockCipher(cipher, cfbBitSize);
this.padding = padding;
macSize = macSizeInBits / 8;
Buffer = new byte[this.cipher.GetBlockSize()];
bufOff = 0;
}
public void Init(ICipherParameters parameters)
{
Reset();
cipher.Init(true, parameters);
}
public int GetMacSize()
{
return macSize;
}
public void Update(byte input)
{
if (bufOff == Buffer.Length) {
cipher.ProcessBlock(Buffer, 0, mac, 0);
bufOff = 0;
}
Buffer[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 = cipher.GetBlockSize();
int num = 0;
int num2 = blockSize - bufOff;
if (input.Length > num2) {
input.Slice(0, num2).CopyTo(Buffer.AsSpan(bufOff));
num += cipher.ProcessBlock(Buffer, mac);
bufOff = 0;
int num3 = num2;
input = input.Slice(num3, input.Length - num3);
while (input.Length > blockSize) {
num += cipher.ProcessBlock(input, mac);
num3 = blockSize;
input = input.Slice(num3, input.Length - num3);
}
}
input.CopyTo(Buffer.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 = cipher.GetBlockSize();
if (padding == null) {
while (bufOff < blockSize) {
Buffer[bufOff++] = 0;
}
} else
padding.AddPadding(Buffer, bufOff);
cipher.ProcessBlock(Buffer, 0, mac, 0);
cipher.GetMacBlock(mac);
mac.AsSpan(0, macSize).CopyTo(output);
Reset();
return macSize;
}
public void Reset()
{
Array.Clear(Buffer, 0, Buffer.Length);
bufOff = 0;
cipher.Reset();
}
}
}