Clef 2-factor for Joomla
Unlike Google Authenticator, Clef does not require you to type codes at every login. Simply hold your phone up to your computer to login with Clef.
After a single login, you will then be automagically logged in to every Clef-enabled site.
This multi-site, 2-factor authentication system even lets you remotely log out of all your sites at once, right from your phone, even if you've left the office in a hurry and forgot to logout.
You can see how it works in this short video:
