C# 實現rtsp Digest Authentication Response

<pre name="code" class="csharp">using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;

namespace RTSP_Digest_Authentication
{
    class Program
    {
        /// <summary>
        /// MD5　32位加密
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        static string md5(string str)
        {
            MD5 md5 = new MD5CryptoServiceProvider();
            byte[] bytes = System.Text.Encoding.UTF8.GetBytes(str);
            bytes = md5.ComputeHash(bytes);
            md5.Clear();

            string ret = "";
            for (int i = 0; i < bytes.Length; i++)
            {
                ret += Convert.ToString(bytes[i], 16).PadLeft(2, '0');//補0
            }
            return ret.PadLeft(32, '0'); //補0

        }


        private static string computeDigestResponse(string username, string userpwd, string realm, string cmd, string nonce, string url)
        {
            // The "response" field is computed as:
            //    md5(md5(<username>:<realm>:<password>):<nonce>:md5(<cmd>:<url>))
            // or, if "fPasswordIsMD5" is True:
            //    md5(<password>:<nonce>:md5(<cmd>:<url>))
            string ha1 = md5(username + ":" + realm + ":" + userpwd);
            string ha2 = md5(cmd + ":" + url);
            string response = md5(ha1 + ":" + nonce + ":" + ha2);

            return response;
        }
        static void Main(string[] args)
        {
            string username = "root";
            string userpwd = "admin";
            string realm = "Operator";
            string cmd = "DESCRIBE";
            string nonce = "3983eb84382ba9811726fc1c2e7fb8be";
            string url = "rtsp://root:[email protected]:554/profile1=r";
            string response = computeDigestResponse(username, userpwd, realm, cmd, nonce, url);
            Console.WriteLine(response);
        }
    }
}