C#一个字符串的加密与解密

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Security.Cryptography;

using System.IO;

  

namespace ConsoleApplication1

{

    class Program

    {

        static string encryptKey = "Oyea";    //定义密钥 

  

        #region 加密字符串 

        /// <summary> /// 加密字符串  

        /// </summary> 

        /// <param name="str">要加密的字符串</param> 

        /// <returns>加密后的字符串</returns> 

        static string Encrypt(string str) 

        {   

            DESCryptoServiceProvider descsp = new DESCryptoServiceProvider();   //实例化加/解密类对象  

    

            byte[] key = Encoding.Unicode.GetBytes(encryptKey); //定义字节数组，用来存储密钥   

   

            byte[] data = Encoding.Unicode.GetBytes(str);//定义字节数组，用来存储要加密的字符串 

     

            MemoryStream MStream = new MemoryStream(); //实例化内存流对象     

  

            //使用内存流实例化加密流对象  

            CryptoStream CStream = new CryptoStream(MStream, descsp.CreateEncryptor(key, key), CryptoStreamMode.Write);    

  

            CStream.Write(data, 0, data.Length);  //向加密流中写入数据     

  

            CStream.FlushFinalBlock();              //释放加密流     

  

            return Convert.ToBase64String(MStream.ToArray());//返回加密后的字符串 

        } 

        #endregion

  

        #region 解密字符串  

        /// <summary> 

        /// 解密字符串  

        /// </summary> 

        /// <param name="str">要解密的字符串</param> 

        /// <returns>解密后的字符串</returns>   

        static string Decrypt(string str) 

        {     

            DESCryptoServiceProvider descsp = new DESCryptoServiceProvider();   //实例化加/解密类对象   

     

            byte[] key = Encoding.Unicode.GetBytes(encryptKey); //定义字节数组，用来存储密钥   

    

            byte[] data = Convert.FromBase64String(str);//定义字节数组，用来存储要解密的字符串 

      

            MemoryStream MStream = new MemoryStream(); //实例化内存流对象     

   

            //使用内存流实例化解密流对象      

            CryptoStream CStream = new CryptoStream(MStream, descsp.CreateDecryptor(key, key), CryptoStreamMode.Write);  

   

            CStream.Write(data, 0, data.Length);      //向解密流中写入数据    

  

            CStream.FlushFinalBlock();               //释放解密流     

  

            return Encoding.Unicode.GetString(MStream.ToArray());       //返回解密后的字符串 

        } 

        #endregion

  

        static void Main(string[] args)

        {

            Console.Write("请输入要加密的字符串：");   //提示输入字符串     

            Console.WriteLine();                  //换行输入  

            string str = Console.ReadLine();     //记录输入的字符串     

            string strNew = Encrypt(str);              //加密字符串     

            Console.WriteLine("加密后的字符串：" + strNew);  //输出加密后的字符串     

            Console.WriteLine("解密后的字符串：" + Decrypt(strNew)); //解密字符串并输出    

            Console.ReadLine();

        }

    }

}