Face Unlock has been a bit of a novelty ever since Google introduced it in Android 4.0, but any sense of security offered by the feature disappeared once it was revealed that it could be easily tricked by a photograph. For Google's part it has always labeled the option as "low-security" and "experimental," but it has now taken a step to stop photo-equipped thieves with a new "Liveness Check" that requires a user to blink before granting access to the phone. The search company has taken a page out of Samsung's book by rolling out the blink-recognition technology, but don't let the change fool you into trusting face unlock just yet. We've seen the system let in two vaguely similar-looking people through the lock screen before, so you're still safer using a PIN for now.