C# 加密/解密

  public byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };  //加密的KEY

        /// DES加密字符串
        ///
        /// 待加密的字符串
        /// 加密密钥,要求为8位
        /// 加密成功返回加密后的字符串，失败返回源串
        [WebMethod]
        public string EncryptDES(string encryptString, string encryptKey)
        {
            try
            {

　　　　　　　　byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));
                　　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, 0, inputByteArray.Length);
                　　cStream.FlushFinalBlock();
               　　 return Convert.ToBase64String(mStream.ToArray());

　　　　}
            catch
            {
                return encryptString;
            }
        }

        /// DES解密字符串
        ///
        /// 待解密的字符串
        /// 解密密钥,要求为8位,和加密密钥相同
        /// 解密成功返回解密后的字符串，失败返源串
        [WebMethod]
        public 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, 0, inputByteArray.Length);
                　　cStream.FlushFinalBlock();
                　　return Encoding.UTF8.GetString(mStream.ToArray());　

　　　　

　　　　}            

　　　　catch {

                　　　　return decryptString;           

　　　　　　  }

       }