c# 字符串加密

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;
using System.IO;

namespace tes2
{
    class Encrypt
    {
        #region "定义加密字串变量"
        private SymmetricAlgorithm mCSP;  //声明对称算法变量
        private const string CIV = "Mi9l/+7Zujhy12se6Yjy111A";  //初始化向量
        private const string CKEY = "jkHuIy9D/9i="; //密钥（常量）
        #endregion
        /// <summary>
        /// 实例化
        /// </summary>
        public Encrypt()
        {
            mCSP = new DESCryptoServiceProvider();  //定义访问数据加密标准 (DES) 算法的加密服务提供程序 (CSP) 版本的包装对象,此类是SymmetricAlgorithm的派生类
        }

        /// <summary>
        /// 加密字符串
        /// </summary>
        /// <param name="Value">需加密的字符串</param>
        /// <returns></returns>
        public  string EncryptString(string Value)
        {
            ICryptoTransform ct; //定义基本的加密转换运算
            MemoryStream ms; //定义内存流
            CryptoStream cs; //定义将内存流链接到加密转换的流
            byte[] byt;
            //CreateEncryptor创建(对称数据)加密对象
            ct = mCSP.CreateEncryptor(Convert.FromBase64String(CKEY), Convert.FromBase64String(CIV)); //用指定的密钥和初始化向量创建对称数据加密标准
            byt = Encoding.UTF8.GetBytes(Value); //将Value字符转换为UTF-8编码的字节序列
            ms = new MemoryStream(); //创建内存流
            cs = new CryptoStream(ms, ct, CryptoStreamMode.Write); //将内存流链接到加密转换的流
            cs.Write(byt, 0, byt.Length); //写入内存流
            cs.FlushFinalBlock(); //将缓冲区中的数据写入内存流，并清除缓冲区
            cs.Close(); //释放内存流
            return Convert.ToBase64String(ms.ToArray()); //将内存流转写入字节数组并转换为string字符
        }

        /// <summary>
        /// 解密字符串
        /// </summary>
        /// <param name="Value">要解密的字符串</param>
        /// <returns>string</returns>
        public string DecryptString(string Value)
        {
            ICryptoTransform ct; //定义基本的加密转换运算
            MemoryStream ms; //定义内存流
            CryptoStream cs; //定义将数据流链接到加密转换的流
            byte[] byt;
            ct = mCSP.CreateDecryptor(Convert.FromBase64String(CKEY), Convert.FromBase64String(CIV)); //用指定的密钥和初始化向量创建对称数据解密标准
            byt = Convert.FromBase64String(Value); //将Value(Base 64)字符转换成字节数组
            ms = new MemoryStream();
            cs = new CryptoStream(ms, ct, CryptoStreamMode.Write);
            cs.Write(byt, 0, byt.Length);
            cs.FlushFinalBlock();
            cs.Close();
            return Encoding.UTF8.GetString(ms.ToArray()); //将字节数组中的所有字符解码为一个字符串
        }
    }
}