Salesforce Authenticator adds an extra layer of security for your online accounts with two-factor authentication. With Salesforce Authenticator, you use your mobile device in addition to your password to verify your logins and other account activity. The app sends you a push notification, and you respond with just a tap. For even more convenience, Salesforce Authenticator can use your mobile device's location services to verify automatically from trusted locations, like your office or home. You can also get a verification code when you need one. Salesforce Authenticator works with the entire Salesforce Platform—Sales Cloud, Service Cloud, Marketing Cloud (ExactTarget), App Cloud, and Analytics Cloud—as well as third-party services that use OATH tokens.
Salesforce Authenticator also supports "old school" two-step authentication on Facebook, Google, Outlook, Dropbox, Evernote, or anything marked "Software Implementation" at http://twofactorauth.org.