ArrayMixer.cs

Uses Sha3 to Shuffle Primitive Arrays

using System;
public class ArrayMixer
{
    private readonly SHA3ModInt _alg;
    private readonly int        _moveSize;
    public ArrayMixer() : this(256, 24)
    {
    }
    public ArrayMixer(int hashSize) : this(hashSize, 24)
    {
    }
    public ArrayMixer(int hashSize, int rounds)
    {
        _alg      = new SHA3ModInt(hashSize, rounds);
        _moveSize = _alg.ComputeHash(2.GetBytes()).Length;
    }
    public byte[] Mix(byte[] buf, int iterations = 1000)
    {
        var bufferSize = buf.Length;
        var lBuffer    = new byte[_moveSize];
        var oBuffer    = new byte[bufferSize];
        for (var i = 0; i < iterations; ++i)
        {
            var bytesSuffled = 0;
            var moveSize     = _moveSize;
            var p            = 0;
            while (true)
            {
                var rBytesShuffle = bufferSize - bytesSuffled;
                if (rBytesShuffle < moveSize)
                    moveSize = rBytesShuffle;
                if (rBytesShuffle <= 0)
                    break;
                Buffer.BlockCopy(buf, p, lBuffer, 0, moveSize);
                lBuffer = _alg.ComputeHash(lBuffer);
                Buffer.BlockCopy(lBuffer, 0, oBuffer, p, moveSize);
                p            += moveSize;
                bytesSuffled += moveSize;
            }
            Buffer.BlockCopy(oBuffer, 0, buf, 0, bufferSize);
        }
        lBuffer.Fill(0);
        oBuffer.Fill(0);
        return buf;
    }
    public ushort[] Mix(ushort[] buf, int iterations = 1000)
    {
        var bb = buf.GetBytes();
        return Mix(bb, iterations).ToUShortArray();
    }
    public uint[] Mix(uint[] buf, int iterations = 1000)
    {
        var bb = buf.GetBytes();
        return Mix(bb, iterations).ToUIntArray();
    }
    public ulong[] Mix(ulong[] buf, int iterations = 1000)
    {
        var bb = buf.GetBytes();
        return Mix(bb, iterations).ToULongArray();
    }
    /// <summary>
    ///     Will round up finalSize to the nearest 8 byte boundary.
    /// </summary>
    /// <param name="ba"></param>
    /// <param name="finalSize"></param>
    /// <returns></returns>
    private static ulong[] ByteArrayToULongArray(byte[] ba, int finalSize)
    {
        var minSize = ba.Length / 8;
        if (finalSize < minSize)
            finalSize = minSize;
        ba = PadULong(ba);
        var os = finalSize / 8;
        if (os * 8 < finalSize)
            os++;
        var result = new ulong[os];
        for (var i = 0; i < ba.Length; i += 8)
            Buffer.BlockCopy(ba, i, result, i, 8);
        return result;
    }
    private static byte[] PadULong(byte[] ba)
    {
        var s = ba.Length % 8;
        switch (s)
        {
            case 0:
                break;
            case 1:
                Array.Resize(ref ba, ba.Length + 7);
                ba[ba.Length - 1] = 0x80;
                ba[ba.Length - 2] = 0x80;
                ba[ba.Length - 3] = 0x80;
                ba[ba.Length - 4] = 0x80;
                ba[ba.Length - 5] = 0x80;
                ba[ba.Length - 6] = 0x80;
                ba[ba.Length - 7] = 0x80;
                break;
            case 2:
                Array.Resize(ref ba, ba.Length + 6);
                ba[ba.Length - 1] = 0x80;
                ba[ba.Length - 2] = 0x80;
                ba[ba.Length - 3] = 0x80;
                ba[ba.Length - 4] = 0x80;
                ba[ba.Length - 5] = 0x80;
                ba[ba.Length - 6] = 0x80;
                break;
            case 3:
                Array.Resize(ref ba, ba.Length + 5);
                ba[ba.Length - 1] = 0x80;
                ba[ba.Length - 2] = 0x80;
                ba[ba.Length - 3] = 0x80;
                ba[ba.Length - 4] = 0x80;
                ba[ba.Length - 5] = 0x80;
                break;
            case 4:
                Array.Resize(ref ba, ba.Length + 4);
                ba[ba.Length - 1] = 0x80;
                ba[ba.Length - 2] = 0x80;
                ba[ba.Length - 3] = 0x80;
                ba[ba.Length - 4] = 0x80;
                break;
            case 5:
                Array.Resize(ref ba, ba.Length + 3);
                ba[ba.Length - 1] = 0x80;
                ba[ba.Length - 2] = 0x80;
                ba[ba.Length - 3] = 0x80;
                break;
            case 6:
                Array.Resize(ref ba, ba.Length + 2);
                ba[ba.Length - 1] = 0x80;
                ba[ba.Length - 2] = 0x80;
                break;
            case 7:
                Array.Resize(ref ba, ba.Length + 1);
                ba[ba.Length - 1] = 0x80;
                break;
        }
        return ba;
    }
    private static void Expand(ulong[] x, int iterations = 1)
    {
        var size = x.Length;
        for (var k = 0; k < iterations; ++k)
        for (var i = 0; i < size; ++i)
        {
            ulong n = 0;
            var   j = 0;
            while (j < size)
            {
                n ^= x[j];
                ++j;
            }
            x[i] = (n << 1) | (n >> 56);
        }
    }
    /// <summary>
    ///     ExpandAndMixArray resizes the array by extrusion then mixes the array using a Sha3 one way hash
    /// </summary>
    /// <param name="ba">The buffer</param>
    /// <param name="size">The final desired size</param>
    /// <param name="iterations">The number of iterations to mix the final array</param>
    public byte[] ExpandAndMixArray(byte[] ba, int size, int iterations = 1000)
    {
        var ula = ByteArrayToULongArray(ba, size);
        Expand(ula, 1);
        var array = ula.GetBytes();
        return Mix(array, iterations);
    }
    public ushort[] ExpandAndMixArray(ushort[] ba, int size, int iterations = 1000)
    {
        var bb = ba.GetBytes();
        return ExpandAndMixArray(bb, size, iterations).ToUShortArray();
    }
    public uint[] ExpandAndMixArray(uint[] ba, int size, int iterations = 1000)
    {
        var bb = ba.GetBytes();
        return ExpandAndMixArray(bb, size, iterations).ToUIntArray();
    }
    public ulong[] ExpandAndMixArray(ulong[] ba, int size, int iterations = 1000)
    {
        var bb = ba.GetBytes();
        return ExpandAndMixArray(bb, size, iterations).ToULongArray();
    }
}

PasswordStretch.cs

Password Stretch using Sha3

Example Code:
var b1   = new byte[0];
        var b2   = new byte[0];
        var salt = new byte[0];
        using (var db = new PasswordStretch("1234567890".ToSecureString(), 16))
        {

            b1   = (byte[]) db.GetBytes(0, 64).Clone();
            salt = db.Salt;
        }

        using (var db = new PasswordStretch("1234567891".ToSecureString(), salt))
        {

            b2 = (byte[]) db.GetBytes(0, 64).Clone();
        }
using System;
using System.Security;
using System.Security.Cryptography;
public class PasswordStretch : IDisposable
{
    private const    int         PacketCount = 4;
    private readonly byte[]      _buffer;
    private readonly byte[]      _salt;
    private readonly SHA3Managed _sha;
    public PasswordStretch(SecureString password) : this(password, 0, 1000)
    {
    }
    public PasswordStretch(SecureString password, int saltSize) : this(password, saltSize, 1000)
    {
    }
    public PasswordStretch(SecureString password, int saltSize, int iterations)
    {
        Iterations = iterations;
        var temp = new byte[0];
        if (saltSize != 0)
        {
            var data = new byte[saltSize];
            new RNGCryptoServiceProvider().GetBytes(data);
            _salt   = data;
            _sha    = new SHA3Managed(512);
            _buffer = new byte[_sha.HashLength * PacketCount];
            _sha.TransformBlock(_salt, 0, _salt.Length, null, 0);
            var pwb = password.GetBytes();
            _sha.TransformBlock(pwb, 0, pwb.Length, null, 0);
            _sha.Finalize();
            temp = _sha.HashValue;
        }
        else
        {
            _sha    = new SHA3Managed(512);
            _buffer = new byte[_sha.HashLength * PacketCount];
            temp    = _sha.ComputeHash(password.GetBytes());
        }
        for (var i = 0; i < PacketCount; i++)
        {
            for (var j = 0; j < Iterations; j++)
                temp = _sha.ComputeHash(temp);
            Buffer.BlockCopy(temp, 0, _buffer, i * _sha.HashLength, _sha.HashLength);
        }
    }
    public PasswordStretch(SecureString password, byte[] salt) : this(password, salt, 1000)
    {
    }
    public PasswordStretch(SecureString password, byte[] salt, int iterations = 1000)
    {
        Iterations = iterations;
        _sha       = new SHA3Managed(512);
        _buffer    = new byte[_sha.HashLength * PacketCount];
        _sha.TransformBlock(salt, 0, salt.Length, null, 0);
        var pwb = password.GetBytes();
        _sha.TransformBlock(pwb, 0, pwb.Length, null, 0);
        _sha.Finalize();
        var temp = _sha.HashValue;
        for (var i = 0; i < PacketCount; i++)
        {
            for (var j = 0; j < Iterations; j++)
                temp = _sha.ComputeHash(temp);
            Buffer.BlockCopy(temp, 0, _buffer, i * _sha.HashLength, _sha.HashLength);
        }
    }
    public byte[] Salt
    {
        get
        {
            if (_salt != null)
                return (byte[]) _salt.Clone();
            return default;
        }
    }
    public int Iterations
    {
        get;
    } = 1000;
    public void Dispose()
    {
        Dispose(true);
        GC.SuppressFinalize(this);
    }
    ~PasswordStretch()
    {
        Dispose();
    }
    public byte[] GetBytes(int offset, int psize)
    {
        if (offset + psize > _buffer.Length)
            throw new Exception("Offset and Size Exceed Buffer Length.");
        var passpart = new byte[psize];
        Buffer.BlockCopy(_buffer, offset, passpart, 0, passpart.Length);
        return passpart;
    }
    private void Dispose(bool disposing)
    {
        if (!disposing)
            return;
        if (_sha != null)
            _sha.Dispose();
        if (_buffer != null)
            Array.Clear(_buffer, 0, _buffer.Length);
        if (_salt == null)
            return;
        Array.Clear(_salt, 0, _salt.Length);
    }
}