This looks like an interesting app for logging in "without passwords" by scanning QR codes using a smart phone and entering a passcode. (I consider a passcode to just be an insecure password, but we'll let that slide for now).

Unfortunately, the app crashes immediately on a 4s with iOS 5.1.1, so I can't test it out. This brings up a concern. If a bad update (like the current one) causes the app to not work with your device, you can not log into anything that uses this for authentication.

This is kind of brilliant. I'm going to give it a shot!