Google authenticator is a software application that implements two-step verification. It provides stronger security than just a username and password alone. The app generates a time-based six-digit code, which the user must provide in addition to their password to log in to Google's services. This is an additional layer of protection since someone who has just the username and password cannot log into the account without access to this second piece of information.

Security can be compromised if any personal information (including email address) is leaked or guessed, even if two-step verification has been activated. For example, an attacker could use Google's “forgot my password” function to reset your account’s password without entering the second step of verification (accessing the personalized key).

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The Google Authenticator is a two-step verification app that works when you sign in to your account. The app generates codes or “tokens” which you must enter when signing in and at the end of your session.

It also creates a backup code which can be used in case your phone is lost, stolen or damaged.

Google authenticator works for all accounts that use Google’s 2-step verification including gmail, blogger, youtube and google play store.