using System;

using System.Text;

using System.Security.Cryptography;

using System.IO;

namespace ConsoleApplication1

{

    class Program

    {

        static void Main(string[] args)

        {

            string a1 = EncryptDES("");

            Console.WriteLine(a1);

            string a2 = DecryptDES(a1);

            Console.WriteLine(a2);

            Console.Read();

        }

        //默认密钥向量

        private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };

        //默认加密密码

        private static string DefEncryptKey = "consmkey";

        /// <summary>

        /// DES加密字符串

        /// </summary>

        /// <param name="encryptString">待加密的字符串</param>

        /// <returns>加密成功返回加密后的字符串，失败返回源串</returns>

        public static string EncryptDES(string encryptString)

        {

            return EncryptDES(encryptString, DefEncryptKey);

        }

        /// <summary>

        /// DES解密字符串

        /// </summary>

        /// <param name="decryptString">待解密的字符串</param>

        /// <returns>解密成功返回解密后的字符串，失败返源串</returns>

        public static string DecryptDES(string decryptString)

        {

            return DecryptDES(decryptString, DefEncryptKey);

        }

        /// <summary>

        /// DES加密字符串

        /// </summary>

        /// <param name="encryptString">待加密的字符串</param>

        /// <param name="encryptKey">加密密钥,要求为8位</param>

        /// <returns>加密成功返回加密后的字符串，失败返回源串</returns>

        public static string EncryptDES(string encryptString, string encryptKey)

        {

            try

            {

                byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(, ));

                byte[] rgbIV = Keys;

                byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);

                DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();

                MemoryStream mStream = new MemoryStream();

                CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);

                cStream.Write(inputByteArray, , inputByteArray.Length);

                cStream.FlushFinalBlock();

                return Convert.ToBase64String(mStream.ToArray());

            }

            catch

            {

                return encryptString;

            }

        }

        /// <summary>

        /// DES解密字符串

        /// </summary>

        /// <param name="decryptString">待解密的字符串</param>

        /// <param name="decryptKey">解密密钥,要求为8位,和加密密钥相同</param>

        /// <returns>解密成功返回解密后的字符串，失败返源串</returns>

        public static string DecryptDES(string decryptString, string decryptKey)

        {

            try

            {

                byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);

                byte[] rgbIV = Keys;

                byte[] inputByteArray = Convert.FromBase64String(decryptString);

                DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();

                MemoryStream mStream = new MemoryStream();

                CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);

                cStream.Write(inputByteArray, , inputByteArray.Length);

                cStream.FlushFinalBlock();

                return Encoding.UTF8.GetString(mStream.ToArray());

            }

            catch

            {

                return decryptString;

            }

        }

    }

}