using System;using System.IO;using System.Security.Cryptography;namespace ConsoleApp{    ///     /// Security 的摘要说明。    ///     public class Security    {        //8字节密钥        const string KEY_64 = "VavicApp";        const string IV_64 = "VavicApp"; //注意了，是8个字符，64位        public Security()        {            //            // TODO: 在此处添加构造函数逻辑            //        }        public static string Encode(string data)        {            byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(KEY_64);            byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(IV_64);            DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();            int i = cryptoProvider.KeySize;            MemoryStream ms = new MemoryStream();            CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateEncryptor(byKey, byIV), CryptoStreamMode.Write);            StreamWriter sw = new StreamWriter(cst);            sw.Write(data);            sw.Flush();            cst.FlushFinalBlock();            sw.Flush();            return Convert.ToBase64String(ms.GetBuffer(), 0, (int)ms.Length);        }        public static string Decode(string data)        {            byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(KEY_64);            byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(IV_64);            byte[] byEnc;            try            {                byEnc = Convert.FromBase64String(data);            }            catch            {                return null;            }            DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();            MemoryStream ms = new MemoryStream(byEnc);            CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateDecryptor(byKey, byIV), CryptoStreamMode.Read);            StreamReader sr = new StreamReader(cst);            return sr.ReadToEnd();        }        public static void Main()        {            string s = "";            string s1 = "";            string s2 = "";            s = Console.ReadLine();            Console.WriteLine(s);            s1 = Security.Encode(s);            Console.WriteLine(s1);            s2 = Security.Decode(s1);            Console.WriteLine(s2);            Console.Read();        }    }}