using System;
using System.Text;
using System.Security.Cryptography;
public static class Md5SignatureDemo
{
        private static readonly char[] HexDigits = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
        // Use the MD5 algorithm to regenerate a signature string with a unique value based on the string in the specified UTF-8 encoding format
        // encryptContent: The signature string is generated using the MD5 algorithm based on the string in this UTF-8 encoding format
        public static string PMakeMd5Signature(this string encryptContent)
        {
            if (string.IsNullOrEmpty(encryptContent))
            {
                return string.Empty;
            }

            byte[] bInputs = Encoding.UTF8.GetBytes(encryptContent);
            // Get the 'MessageDigest' object of the MD5 digest algorithm
            var oMd5 = MD5.Create();
            // Updates the summary with the specified bytes
            oMd5.ComputeHash(bInputs);
            // Get ciphertext
            byte[] bHashes = oMd5.Hash;
            // Convert the ciphertext into hexadecimal string form
            int iLen = bHashes.Length;
            char[] cBuffers = new char[iLen * 2];
            int j = 0;
            for (int i = 0; i < iLen; i++)
            {
                byte bZero = bHashes[i];
                cBuffers[j++] = HexDigits[(bZero >> 4) & 0xf];
                cBuffers[j++] = HexDigits[bZero & 0xf];
            }

            string sRet = new string(cBuffers);

            return sRet;
        }
}