/// <summary>        /// DES加密        /// </summary>        /// <param name="sourceString">需要加密字符串</param>        /// <param name="key">加密密钥</param>        /// <param name="iv"></param>        /// <returns></returns>        public static string Encrypt(string sourceString, string key, string iv)        {            try            {                key = key.Substring(0,8);                iv = iv.Substring(0, 8);                byte[] btKey = Encoding.UTF8.GetBytes(key);                byte[] btIV = Encoding.UTF8.GetBytes(iv);                DESCryptoServiceProvider des = new DESCryptoServiceProvider();                using (MemoryStream ms = new MemoryStream())                {                    byte[] inData =http://www.mamicode.com/ Encoding.UTF8.GetBytes(sourceString);                    try                    {                        using (CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(btKey, btIV), CryptoStreamMode.Write))                        {                            cs.Write(inData, 0, inData.Length);                            cs.FlushFinalBlock();                        }                        return Convert.ToBase64String(ms.ToArray());                    }                    catch                    {                        return sourceString;                    }                }            }            catch(Exception ex) { return ex+"cath DES加密出错"; }        }        /// <summary>        /// DES解密字符串        /// </summary>        /// <param name="encryptedString"></param>        /// <param name="key"></param>        /// <param name="iv"></param>        /// <returns></returns>        public static string Decrypt(string encryptedString, string key, string iv)        {            key = key.Substring(0, 8);            iv = iv.Substring(0, 8);            byte[] btKey = Encoding.UTF8.GetBytes(key);            byte[] btIV = Encoding.UTF8.GetBytes(iv);            DESCryptoServiceProvider des = new DESCryptoServiceProvider();            using (MemoryStream ms = new MemoryStream())            {                byte[] inData =http://www.mamicode.com/ Convert.FromBase64String(encryptedString);                try                {                    using (CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(btKey, btIV), CryptoStreamMode.Write))                    {                        cs.Write(inData, 0, inData.Length);                        cs.FlushFinalBlock();                    }                    return Encoding.UTF8.GetString(ms.ToArray());                }                catch                {                    return encryptedString;                }            }        }