Authy 2-Factor Authentication is a two-step verification app that lets you add an additional layer of security to your device. The app is perfectly compatible with Facebook, Dropbox, Amazon, Gmail, and many more apps. Also, it's one of the preferred tools for protecting bitcoin wallets.
Authy 2-Factor Authentication is a really interesting alternative to Google Authenticator, the two-step verification tool from Google, which offers similar features. Plus, it does everything from a convenient and attractive interface.