Two-factor authentication is a process for improve your “login / password” operation by adding an extra code generated by a dedicated service.
The idea today is to improve the security of you ssh and your gnome login for prevent people to login on your linux desktop.
For accomplished such task, we will use the google autheticator service, because it s reliable, can get your code via sms or generated from mobile app, and also it s free
This is a brilliant tutorial i invite you to follow step by step and let us know how it went, should work liek a breeze
How secure you linux using two-factor with google authenticator