1.MD5 16位加密实例
using System;
using System.Collections.Generic;
using System.Text;
using System.Security.Cryptography;

namespace md5
{
    
class Program
    
{
        
static void Main(string[] args)
        
{
             Console.WriteLine(UserMd5(
"8"));
             Console.WriteLine(GetMd5Str(
"8"));
         }

        
/// <summary>
        
/// MD5 16位加密 加密后密码为大写
        
/// </summary>
        
/// <param name="ConvertString"></param>
        
/// <returns></returns>

        public static string GetMd5Str(string ConvertString)
        
{
             MD5CryptoServiceProvider md5
= new MD5CryptoServiceProvider();
            
string t2 = BitConverter.ToString(md5.ComputeHash(UTF8Encoding.Default.GetBytes(ConvertString)), 4, 8);
             t2
= t2.Replace("-", "");
            
return t2;
         }

  /// <summary>
        
/// MD5 16位加密 加密后密码为小写
        
/// </summary>
        
/// <param name="ConvertString"></param>
        
/// <returns></returns>

        public static string GetMd5Str(string ConvertString)
        
{
             MD5CryptoServiceProvider md5
= new MD5CryptoServiceProvider();
            
string t2 = BitConverter.ToString(md5.ComputeHash(UTF8Encoding.Default.GetBytes(ConvertString)), 4, 8);
             t2
= t2.Replace("-", "");

            t2 = t2.ToLower();

             return t2;
         }



        
/// <summary>
        
/// MD5 32位加密
        
/// </summary>
        
/// <param name="str"></param>
        
/// <returns></returns>

       static  string UserMd5(string str)
        
{
            
string cl = str;
            
string pwd = "";
             MD5 md5
= MD5.Create();//实例化一个md5对像
            
// 加密后是一个字节类型的数组,这里要注意编码UTF8/Unicode等的选择 
            byte[] s = md5.ComputeHash(Encoding.UTF8.GetBytes(cl));
            
// 通过使用循环,将字节类型的数组转换为字符串,此字符串是常规字符格式化所得
            for (int i = 0; i < s.Length; i++)
            
{
                
// 将得到的字符串使用十六进制类型格式。格式后的字符是小写的字母,如果使用大写(X)则格式后的字符是大写字符

                 pwd
= pwd + s[i].ToString("X");
                
             }

            
return pwd;
         }

     }

}

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

public static string StringToMD5Hash(string inputString)
        {
            MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
            byte[] encryptedBytes = md5.ComputeHash(Encoding.ASCII.GetBytes(inputString));
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < encryptedBytes.Length; i++)
            {
                sb.AppendFormat("{0:x2}", encryptedBytes[i]);
            }
            return sb.ToString();
        }