Having a password isn't really enough these days. If you have a website with sensitive information you should really consider 2-factor authentication, where instead of just a password you also need a code from your phone.
The add-on works really well and adds that extra layer of security for your peace of mind!

This is exactly what i have been waiting for. One of my clients has been asking to use 2 step login like this as they feel the information held on some of there pages is really sensitive.

This plugin is perfect. Really steps up security and is easy to setup, use and has saved me loads of programming time and effort.