用C#实现MD5算法

using System;
using System.Text;
using System.Security.Cryptography;

namespace Common
{
/// <summary>
/// 一个实现MD5散列字符串的类
/// 做者：周公
/// 日期：2007
/// </summary>
public sealed class MD5Hashing
       {
private static MD5 md5 = MD5.Create();
//私有化构造函数
private MD5Hashing()
               {
               }
/// <summary>
/// 使用utf8编码将字符串散列
/// </summary>
/// <param name="sourceString">要散列的字符串</param>
/// <returns>散列后的字符串</returns>
public static string HashString( string sourceString)
            {
return HashString(Encoding.UTF8, sourceString);
            }
/// <summary>
/// 使用指定的编码将字符串散列
/// </summary>
/// <param name="encode">编码</param>
/// <param name="sourceString">要散列的字符串</param>
/// <returns>散列后的字符串</returns>
public static string HashString(Encoding encode, string sourceString)
               {
byte[] source = md5.ComputeHash(encode.GetBytes(sourceString));
                       StringBuilder sBuilder = new StringBuilder();
for ( int i = 0; i < source.Length; i++)
                       {
                               sBuilder.Append(source[i].ToString( "x2"));
                       }
return sBuilder.ToString();
               }
       }
}