public static string byte2hex(byte[] abyte0)

        {

            StringBuilder sb = new StringBuilder();

            for (int i = ; i<abyte0.Length; i++)

            {

                if ((abyte0[i] & 0xff) < )

                {

                    sb.Append("");

                }

                sb.Append(Convert.ToString((long)abyte0[i] & (long), ));

            }

            return sb.ToString();

        }

 public static string MD5Encrypt(string json)

        {

            MD5 md5Hash = MD5.Create();

            // Convert the input string to a byte array and compute the hash.

            byte[] data = md5Hash.ComputeHash(Encoding.UTF8.GetBytes(json));

            return byte2hex(data);

        }