using System;

using System.Collections.Generic;

using System.Linq;

using Microsoft.AspNetCore.WebUtilities;

​

​

class Program

{

    static void Main(string[] args)

    {

        var original = "MThLHciL42HhaGrdhbVWue8p6+Npj/J4hVe0/NAwiO4=";

        var newValue = Uri.EscapeDataString(original);      

        var bytes = Convert.FromBase64String(original);

        var encoded = WebEncoders.Base64UrlEncode(bytes);

        var decode1 = WebEncoders.Base64UrlDecode(encoded);

        var decode2 = WebEncoders.Base64UrlDecode(original);

        Console.WriteLine(Convert.ToBase64String(decode1));

        Console.WriteLine(Convert.ToBase64String(decode2));     

        Console.WriteLine(newValue);

        Console.WriteLine(encoded);

    }

}

​