Two factor authentication using google authenticator in own asp net project


Two-factor authentication (2FA) is a security measure that adds an extra layer of protection to your ASP.NET project. It requires to provide two forms of identification before granting access to their . One popular method of implementing 2FA is by using Google Authenticator, a mobile app that generates time- one-time passwords (TOTP).

Setting Up Google Authenticator

Before we can integrate Google Authenticator into our ASP.NET project, we need to set it up. First, download the Google Authenticator app from your mobile device's app store. Once , open the app and the instructions to set it up. This usually involves scanning a QR code or manually entering a secret key provided by the ASP.NET project.

Implementing Two-Factor Authentication in ASP.NET

To implement two-factor authentication using Google Authenticator in your ASP.NET project, you will need to install the Google Authenticator NuGet package. Open your project in Visual Studio and to the Package Console. Run the following command to install the package:

Install-Package Google.Authenticator

Once the package is installed, you can start implementing two-factor authentication in your ASP.NET project. First, create a new instance of the TwoFactorAuthenticator class:

var authenticator = new TwoFactorAuthenticator();

Next, a secret key for the user. This key will be used to generate the one-time passwords:

var secretKey = authenticator.GenerateRandomSecretKey();

Store this secret key securely in your database or any other secure storage. Associate it with the user's account.

Enabling Two-Factor Authentication for a User

To enable two-factor authentication for a user, you need to provide them with a QR code or a manual entry key. This will allow them to add your ASP.NET project to their Google Authenticator app. Here's an example of how to generate a QR code:

var qrCodeUrl = authenticator.GenerateQrCodeUri("YourAppName", "", secretKey);

You can then display this QR code to the user, or provide them with the manual entry key. Once the user adds your ASP.NET project to their Google Authenticator app, they will start receiving one-time passwords.

Verifying Two-Factor Authentication

To the user's two-factor authentication, you need to compare the one-time password entered by the user with the one by Google Authenticator. Here's an example of how to do this:

var isTwoFactorCodeValid = authenticator.ValidateTwoFactorPIN(secretKey, userEnteredCode);

If isTwoFactorCodeValid is true, the user has entered a valid one-time password and can be granted access to their account. Otherwise, access should be denied.


Implementing two-factor authentication using Google Authenticator in your ASP.NET project adds an extra layer of security to protect user accounts. By following the steps outlined in this article, you can easily integrate this security measure into your project and enhance the overall security of your application.

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