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 "定義加密字串變量"
        private SymmetricAlgorithm mCSP;  //聲明對稱算法變量
        private const string CIV = "Mi9l/+7Zujhy12se6Yjy111A";  //初始化向量
        private const string CKEY = "jkHuIy9D/9i="; //密鑰（常量）
        #endregion
        /// <summary>
        /// 實例化
        /// </summary>
        public Encrypt()
        {
            mCSP = new DESCryptoServiceProvider();  //定義訪問數據加密標准 (DES) 算法的加密服務提供程序 (CSP) 版本的包裝對象,此類是SymmetricAlgorithm的派生類
        }

        /// <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; //定義基本的加密轉換運算
            MemoryStream ms; //定義內存流
            CryptoStream cs; //定義將內存流鏈接到加密轉換的流
            byte[] byt;
            //CreateEncryptor創建(對稱數據)加密對象
            ct = mCSP.CreateEncryptor(Convert.FromBase64String(CKEY), Convert.FromBase64String(CIV)); //用指定的密鑰和初始化向量創建對稱數據加密標准
            byt = Encoding.UTF8.GetBytes(Value); //將Value字符轉換為UTF-8編碼的字節序列
            ms = new MemoryStream(); //創建內存流
            cs = new CryptoStream(ms, ct, CryptoStreamMode.Write); //將內存流鏈接到加密轉換的流
            cs.Write(byt, 0, byt.Length); //寫入內存流
            cs.FlushFinalBlock(); //將緩沖區中的數據寫入內存流，並清除緩沖區
            cs.Close(); //釋放內存流
            return Convert.ToBase64String(ms.ToArray()); //將內存流轉寫入字節數組並轉換為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; //定義基本的加密轉換運算
            MemoryStream ms; //定義內存流
            CryptoStream cs; //定義將數據流鏈接到加密轉換的流
            byte[] byt;
            ct = mCSP.CreateDecryptor(Convert.FromBase64String(CKEY), Convert.FromBase64String(CIV)); //用指定的密鑰和初始化向量創建對稱數據解密標准
            byt = Convert.FromBase64String(Value); //將Value(Base 64)字符轉換成字節數組
            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()); //將字節數組中的所有字符解碼為一個字符串
        }
    }
}