Face Unlock was one of the coolest new features in Android 4.0 Ice Cream Sandwich, but while having your phone recognize your face sounds like a fun (it is) way to access your device, it definitely isn’t among the most secure ones.
Why? Well, you can easily trick the phone into thinking it’s seeing your face when you’re actually showing it a picture of yourself. With Jelly Bean things have improved as Google has now added a feature it calls “Liveness check”
that basically asks you to blink in a certain moment and only then unlocks the phone. Now, that’s something a photograph can’t do and definitely an elegant solution making it harder to crack the mechanism.
Is it still possible to trick Face Unlock, though? Certainly. All it takes is a bit of tech savvy to craft an animation out of still photos with you with open and closed eyes, and then play it to your phone’s camera from another display. But still, that’s much harder than just showing a picture, isn’t it?
Anyway, we’d only use Face Unlock for the fun and coolness of it, not for real safety, and we’d advise you to do the same.