Authenticator adds a second layer of security for your online accounts. This works by generating one-time passwords on your mobile devices which can be used in conjunction with your normal password to make your login nearly impossible to hack. These passwords can be generated even when your phone is in airplane mode.

FreeOTP works with many of the great online services you already use, including Google, Facebook, Evernote, GitHub and many more! FreeOTP also may work for your private corporate security if they implement the standardised TOTP or HOTP protocols. This includes great enterprise solutions like FreeIPA.