In our previous post, explains you the login system using PHP with PDO connection. Here is an extra feature that can be added to login system for an extra layer of security. It is 2 factor authentication using Google Authenticator App for Android/iPhone. Your account could be at risk of having your password stolen. 2 step verification can protect from misuse of your account if someone have your password, because logging into your account always require a security code(this verification code is uniquely designed for your account, if you opt for verification code, an unique code is sent to your mobile for every 30-60 seconds) in the second step after you enter your password.