On the SitePoint PHP blog there's a tutorial posted from Christopher Thomas showing you how to integrate two-factor authentication into your Laravel application with a Google Authenticator-compatible library, helping to secure your site even better than just one level of authentication and authorization.
In this tutorial, we will use Laravel and Google Authenticator to demonstrate how to implement 2FA in a webapp. Google Authenticator is just one implementation of the Time-Based One-Time Password (TOTP) algorithm, RFC 6238. This industry standard is used in a lot of various 2FA solutions.
[...] How the TOTP works is that the server generates a secret key. This secret key is then passed to the user. The secret key is used in combination with the current Unix timestamp to generate a six digit number, using a keyed-hash message authentication code (HMAC) based algorithm. This six digit number is the OTP. It changes every 30 seconds.
They start with a clean slate and build a new Laravel project out and include the libraries needed for the TFA support: pragmarx/google2fa and paragonie/constant_time_encoding. You then add in the provider to Laravel's config, build out the models/tables to hold the two-factor information and add a few routes to handle the validation steps. They also include the details in building out the controllers, updating the AuthController for the new step in the authentication flow and how to handle the code validation. The code for all of this (as well as the views) is included as well as screenshots showing the setup and usage of the two-factor handling in the standard authentication flow.