C#实现MD5加密算法源码详解

//MD5.cs
//-----------------------------------
using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Collections;

namespace Encrypt.Algorithm
{
    ///<summary >
    /// MD5加密算法
    ///</summary> 
    public class MD5
    {
        //static state variables
        private static UInt32 A;
        private static UInt32 B;
        private static UInt32 C;
        private static UInt32 D;

        //number of bits to rotate in tranforming
        private const int S11 = 7;
        private const int S12 = 12;
        private const int S13 = 17;
        private const int S14 = 22;
        private const int S21 = 5;
        private const int S22 = 9;
        private const int S23 = 14;
        private const int S24 = 20;

        private const int S31 = 4;
        private const int S32 = 11;
        private const int S33 = 16;
        private const int S34 = 23;
        private const int S41 = 6;
        private const int S42 = 10;
        private const int S43 = 15;
        private const int S44 = 21;
        private static UInt32 F(UInt32 x, UInt32 y, UInt32 z)
        {
            return (x & y) | ((~x) & z);
        }
        private static UInt32 G(UInt32 x, UInt32 y, UInt32 z)
        {
            return (x & z) | (y & (~z));
        }
        private static UInt32 H(UInt32 x, UInt32 y, UInt32 z)
        {
            return x ^ y ^ z;
        }
        private static UInt32 I(UInt32 x, UInt32 y, UInt32 z)
        {
            return y ^ (x | (~z));
        }
        private static void FF(ref UInt32 a, UInt32 b, UInt32 c, UInt32 d, UInt32 mj, int s, UInt32 ti)
        {
            a = a + F(b, c, d) + mj + ti;
            a = a << s | a >> (32 - s);
            a += b;
        }