Two factor authentication is becoming more popular as more and more sites get hacked based on password alone.
- GA Login uses the Google Authenticator software and smartphone app
- Two Factor Auth - TFA currently uses sms messages or emails, but is intended to be a framework.
- Duo Security integrates the Duo Security tool which includes app, sms, phone callback, and hardware tokens
- Yubikey relies on a hardware device that you plug into your usb port
- Multifactorauth - which requires you to enter a non-evolving pin over your phone to get access. Also has an aim of becoming a bit of a framework module for TFA over Voip.
- FACTOR TWO works similarly to GA Login but doesn't rely on Google or smartphone app.
- InWebo Strong Authentication integrates the In-Webo tokenless "Strong Authentication" service.