I’ve been running the websec.io site for a few months now and have written up articles on a pretty wide range of topics. Recently, though, I had a lot of fun working up a series of posts (three of them) about implementing two-factor authentication in your PHP applications. I went through three different methods (two API-based services and Google Authenticator) and wrote up articles about using them. These posts were also accompanied by some custom development work I posted over on Github. The idea was to lower the bar as far down as possible and make it dead easy to implement in any application.