using System;

using System.Net.Http;

using System.Threading;

using System.Threading.Tasks;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {       

        Console.WriteLine(GetAntiforgeryTokenAsync(default).Result);

    }

    public static Task<string> GetAntiforgeryTokenAsync(CancellationToken cancellationToken) 

    {

        cancellationToken.ThrowIfCancellationRequested();

        return GetAntiforgeryTokenAsyncInternal(cancellationToken); 

    }

    private static async Task<string> GetAntiforgeryTokenAsyncInternal(CancellationToken cancellationToken)

    {       

        // .Net Fiddle hack

        HttpClientHandler handler = new HttpClientHandler();

        handler.ServerCertificateCustomValidationCallback = (_, __, ___, s) => true;

        handler.AllowAutoRedirect = true;

        using HttpClient client = new HttpClient(handler);

        using HttpRequestMessage request = new HttpRequestMessage();

        request.Method = HttpMethod.Get;

        request.RequestUri = new Uri("https://passport.secib.fr/Account/Login?ReturnUrl=%2Fpassword%2Fchange");     

        using HttpResponseMessage response = await client.SendAsync(request);

        if(!response.IsSuccessStatusCode)

        {

            throw new InvalidOperationException("Cannot get antiforgery token");

        }

        string body = await response.Content.ReadAsStringAsync();

        Match match = Regex.Match(body, "<input name=\"__RequestVerificationToken\" type=\"hidden\" value=\"([^\"]*)\">");

        Console.WriteLine(match.Groups.Count);

        return "";

    }

}