using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Security.Cryptography;

namespace MD51X

{

    class MD

    {

        private string sString;

        public MD(string text)

        {

            sString=text;

        }

        /// <summary>

        /// MD5算法算出的字符串

        /// </summary>

        /// <returns>算出的字符串</returns>

        public string ToString()

        {

            return getMd5Hash(sString);

        }      

        private string getMd5Hash(string input)

        {

            MD5 md5Hasher = MD5.Create();

            byte[] data = md5Hasher.ComputeHash(Encoding.Default.GetBytes(input));

            StringBuilder sBuilder = new StringBuilder();

            for (int i = 0; i < data.Length; i++)

            {

                sBuilder.Append(data[i].ToString("x2"));

            }

            return sBuilder.ToString();

        }

    }

}

上面的是MD5加密的类（一定要加这个命名空间：using System.Security.Cryptography;）

下面是主程序

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace MD51X

{

    class Program

    {

        static void Main(string[] args)

        {

           

            Console.WriteLine("请输入，加密字符串");

            string pwd = Console.ReadLine();

            string Md5password = (new MD(pwd)).ToString();

            Console.WriteLine("输出加密后的字符");

            Console.WriteLine(Md5password);

            Console.ReadLine();

        }

    }

}

下面试运算结果