Tag: 256Bit

FNV1a 128…1024Bit Hashing BigInteger

using System;
using System.Numerics;
using System.Security.Cryptography;
using static System.Globalization.CultureInfo;
using static System.Globalization.NumberStyles;
using static System.Numerics.BigInteger;
[Serializable]
public class FNV1aX : HashAlgorithm
{
    private static int        _bitWidth;
    private        BigInteger _h1;
    public         BigInteger _mod;
    public         BigInteger _offset;
    private        BigInteger _prime;
    public FNV1aX(int bitWidth = 128)
    {
        _bitWidth = bitWidth;
        SetBitWidthPom(bitWidth);
        _h1 = _offset;
    }
    public override int HashSize => _bitWidth;
    private void SetBitWidthPom(int bitWidth)
    {
        switch (bitWidth)
        {
            //case 32:
            //    _prime  = Parse("1000193", AllowHexSpecifier, InvariantCulture);
            //    _offset = Parse("811c9dc5", AllowHexSpecifier, InvariantCulture);
            //    _mod    = Parse("10000000", AllowHexSpecifier, InvariantCulture);
            //    break;
            //case 64:
            //    _prime  = Parse("100000001B3", AllowHexSpecifier, InvariantCulture);
            //    _offset = Parse("CBF29CE484222325", AllowHexSpecifier, InvariantCulture);
            //    _mod    = Parse("1000000000000000", AllowHexSpecifier, InvariantCulture);
            //    break;
            case 128:
                _prime = Parse("0000000001000000000000000000013B", AllowHexSpecifier, InvariantCulture);
                _offset = Parse("6c62272e07bb014262b821756295c58d", AllowHexSpecifier, InvariantCulture);
                _mod = Parse("10000000000000000000000000000000", AllowHexSpecifier, InvariantCulture);
                break;
            case 256:
                _prime  = Parse("0000000000000000000001000000000000000000000000000000000000000163", AllowHexSpecifier, InvariantCulture);
                _offset = Parse("dd268dbcaac550362d98c384c4e576ccc8b1536847b6bbb31023b4c8caee0535", AllowHexSpecifier, InvariantCulture);
                _mod    = Parse("1000000000000000000000000000000000000000000000000000000000000000", AllowHexSpecifier, InvariantCulture);
                break;
            case 512:
                _prime = Parse("00000000000000000000000000000000000000000100000000000000000000000000000000000000000000000000000000000000000000000000000000000157",
                    AllowHexSpecifier, InvariantCulture);
                _offset = Parse("b86db0b1171f4416dca1e50f309990acac87d059c90000000000000000000d21e948f68a34c192f62ea79bc942dbe7ce182036415f56e34bac982aac4afe9fd9",
                    AllowHexSpecifier, InvariantCulture);
                _mod = Parse("10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000", AllowHexSpecifier,
                    InvariantCulture);
                break;
            case 1024:
                _prime = Parse(
                    "000000000000000000000000000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000018D",
                    AllowHexSpecifier, InvariantCulture);
                _offset = Parse(
                    "0000000000000000005f7a76758ecc4d32e56d5a591028b74b29fc4223fdada16c3bf34eda3674da9a21d9000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000004c6d7eb6e73802734510a555f256cc005ae556bde8cc9c6a93b21aff4b16c71ee90b3",
                    AllowHexSpecifier, InvariantCulture);
                _mod = Parse(
                    "1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
                    AllowHexSpecifier, InvariantCulture);
                break;
        }
    }
    public override void Initialize()
    {
        _h1 = _offset;
    }
    protected override void HashCore(byte[] bytes, int ibStart, int cbSize)
    {
        Hash(bytes, ibStart, cbSize);
    }
    private unsafe void Hash(byte[] bytes, int ibStart, int cbSize)
    {
        if (bytes == null)
            return;
        if (ibStart >= bytes.Length || cbSize > bytes.Length)
            return;
        fixed (byte* pb = bytes)
        {
            var nb = pb + ibStart;
            while (cbSize >= 8)
            {
                _h1    ^= *(ulong*) nb;
                _h1    *= _prime;
                _h1    %= _mod;
                nb     += 8;
                cbSize -= 8;
            }
            switch (cbSize & 7)
            {
                case 7:
                    _h1 ^= *(ulong*) (nb + 6);
                    _h1 *= _prime;
                    _h1 %= _mod;
                    goto case 6;
                case 6:
                    _h1 ^= *(ulong*) (nb + 5);
                    _h1 *= _prime;
                    _h1 %= _mod;
                    goto case 5;
                case 5:
                    _h1 ^= *(ulong*) (nb + 4);
                    _h1 *= _prime;
                    _h1 %= _mod;
                    goto case 4;
                case 4:
                    _h1 ^= *(ulong*) (nb + 3);
                    _h1 *= _prime;
                    _h1 %= _mod;
                    goto case 3;
                case 3:
                    _h1 ^= *(ulong*) (nb + 2);
                    _h1 *= _prime;
                    _h1 %= _mod;
                    goto case 2;
                case 2:
                    _h1 ^= *(ulong*) (nb + 1);
                    _h1 *= _prime;
                    _h1 %= _mod;
                    goto case 1;
                case 1:
                    _h1 ^= *nb;
                    _h1 *= _prime;
                    _h1 %= _mod;
                    break;
            }
        }
    }
    protected override byte[] HashFinal()
    {
        return _h1.ToByteArray();
    }
}