using System;

using System.Security.Cryptography;

using System.Text;

public class Program

{

    public static void Main()

    {

        string username_net = "13001446";

        string password_net = "E@123456";

        string token = "4e59b9c37351fb752248d710e68c1eef";

        string auth = username_net + ":" + Hash(username_net.ToUpper() + "|" + password_net + "|" + token).ToString();

        string authHeader = "Basic " + Base64Encode(auth);

        Console.WriteLine(authHeader);

    }

    public static string Base64Encode(string plainText)

    {

        var plainTextBytes = Encoding.UTF8.GetBytes(plainText);

        return Convert.ToBase64String(plainTextBytes);

    }

​

    public static string Hash(string ToHash)

    {

        Encoder enc = Encoding.ASCII.GetEncoder();

        byte[] data = new byte[ToHash.Length];

        enc.GetBytes(ToHash.ToCharArray(), 0, ToHash.Length, data, 0, true);

        MD5 md5 = new MD5CryptoServiceProvider();

        byte[] result = md5.ComputeHash(data);

        return BitConverter.ToString(result).Replace("-", "").ToLower();

    }

}