Google's two-factor authentication application for mobile devices. After logging into a site that uses Authenticator, users receive a phone message with a unique numeric code for that login session.

You'll get a QR code or setup key. Next, open the Google Authenticator app and tap the plus sign. Record the 2FA code/key. Whenever you're asked for the 2FA code, open Google Authenticator to find it.

Microsoft Authenticator is a security app for two-factor authentication. It competes directly with Google Authenticator, Authy, LastPass Authenticator, and others. You may run into the app when ...