SkeinMac
Implementation of the Skein parameterised MAC function in 256, 512 and 1024 bit block sizes,
based on the ThreefishEngineThreefish tweakable block cipher.
using Org.BouncyCastle.Crypto.Digests;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Utilities;
using System;
namespace Org.BouncyCastle.Crypto.Macs
{
public class SkeinMac : IMac
{
public const int SKEIN_256 = 256;
public const int SKEIN_512 = 512;
public const int SKEIN_1024 = 1024;
private readonly SkeinEngine engine;
public string AlgorithmName {
get {
int num = engine.BlockSize * 8;
string str = num.ToString();
num = engine.OutputSize * 8;
return "Skein-MAC-" + str + "-" + num.ToString();
}
}
public SkeinMac(int stateSizeBits, int digestSizeBits)
{
engine = new SkeinEngine(stateSizeBits, digestSizeBits);
}
public SkeinMac(SkeinMac mac)
{
engine = new SkeinEngine(mac.engine);
}
public void Init(ICipherParameters parameters)
{
SkeinParameters skeinParameters;
if (parameters is SkeinParameters)
skeinParameters = (SkeinParameters)parameters;
else {
if (!(parameters is KeyParameter))
throw new ArgumentException("Invalid parameter passed to Skein MAC init - " + Platform.GetTypeName(parameters));
skeinParameters = new SkeinParameters.Builder().SetKey(((KeyParameter)parameters).GetKey()).Build();
}
if (skeinParameters.GetKey() == null)
throw new ArgumentException("Skein MAC requires a key parameter.");
engine.Init(skeinParameters);
}
public int GetMacSize()
{
return engine.OutputSize;
}
public void Reset()
{
engine.Reset();
}
public void Update(byte inByte)
{
engine.Update(inByte);
}
public void BlockUpdate(byte[] input, int inOff, int len)
{
engine.BlockUpdate(input, inOff, len);
}
public void BlockUpdate(ReadOnlySpan<byte> input)
{
engine.BlockUpdate(input);
}
public int DoFinal(byte[] output, int outOff)
{
return engine.DoFinal(output, outOff);
}
public int DoFinal(Span<byte> output)
{
return engine.DoFinal(output);
}
}
}