To Add Google Two Factor Authentication using Google Authenticator you need the following
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Security.Cryptography;
using System.Text;
using System.Web.Profile;
using System.Web.Security;
using Google.Authenticator;
To get the Google.Authenticator; check here https://www.nuget.org/packages/GoogleAuthenticator
now setting up the Google authentication.
TwoFactorAuthenticator tfa = new TwoFactorAuthenticator();
var setupInfo = tfa.GenerateSetupCode("Name of the app", "More info ABout the App", "SuperSecretKeyGoesHere", 300 , 300); //the width and height of the Qr Code in pixels
string qrCodeImageUrl = setupInfo.QrCodeSetupImageUrl; // assigning the Qr code information + URL to string
string manualEntrySetupCode = setupInfo.ManualEntryKey; // show the Manual Entry Key for the users that don't have app or phone
Image1.ImageUrl = qrCodeImageUrl;// showing the qr code on the page "linking the string to image element"
Label1.Text = manualEntrySetupCode; // showing the manual Entry setup code for the users that can not use their phone
you can change the SuperSecretKeyGoesHere to any value that you want, but make sure it has more than 10 character otherwise the manual entry key that is generated will not work. Now you can check the user input with text box and button click
this bit will look at the user entry and see if its ok
string user_enter=TextBox1.Text;
TwoFactorAuthenticator tfa = new TwoFactorAuthenticator();
bool isCorrectPIN = tfa.ValidateTwoFactorPIN("SuperSecretKeyGoesHere", user_enter);
if (isCorrectPIN == true)
{
Label2.Text = "i am cool";
}
else
{
Label2.Text = "i am Fool";
}