using System;

using System.Web;

public class Program

{

    public static void Main()

    {

        string obfuscatedGuid = "%2fpAUV3qGEe%2bsIAANOi9%2bsg%3d%3d";

        string guidString = "291dad89-5876-ef11-a670-6045bd8bfded";

        Guid parsedGuid = Guid.Parse(guidString);

        Console.WriteLine($"Obfuscated:  \t{obfuscatedGuid}\nDeobfuscated:\t{DeObfuscateGuid(obfuscatedGuid)}");

        Console.WriteLine("=============");

        Console.WriteLine($"Deobfuscated:\t{guidString}\nObfuscated:  \t{ObfuscateGuid(parsedGuid)}");

        string ObfuscateGuid(Guid guid)

        {

            byte[] guidBytes = guid.ToByteArray();

            string base64Encoded = Convert.ToBase64String(guidBytes);

            string urlEncoded = HttpUtility.UrlEncode(base64Encoded);

            return urlEncoded;          

        }

        Guid DeObfuscateGuid(string obfuscatedGuid)

        {

            try

            {

                byte[] guidBytes = Convert.FromBase64String(obfuscatedGuid);

                return new Guid(guidBytes);

            }

            catch (FormatException)

            {

                string urlDecoded = HttpUtility.UrlDecode(obfuscatedGuid);

                byte[] guidBytes = Convert.FromBase64String(urlDecoded);

                return new Guid(guidBytes);

            }

        }

    }

}