This could also be used for non web site logins with some work - I'm thinking of a PAM module that puts a QR code up on the login screen. This likely would be

This could also be used for non web site logins with some work - I'm thinking of a PAM module that puts a QR code up on the login screen. This likely would be more work than it is worth. If it were done, logging in to a non-graphical system (e.g. ssh / console) would be an interesting challenge - theoretically, you could make ASCII-art QR codes. ;-) As a more elaborate version, this could provide a challenge-response authentication where the QR code is the challenge, an Android/iPhone app does a crypto hash to sign the challenge and sends it to the home office to complete the authentication. Unfortunately, webcams are not consistent WRT presence and access, otherwise the phone app could generate a signed QR code and send it back to the home office via the webcam. The primary advantage here would be if you did not have internet access via your cell phone, e.g. neither cell phone coverage nor a WiFi hotspot was available.