Google now has a patent that will allow users to unlock their smartphones and tablets by using specific facial expressions instead of typing in passwords.
Google Android phones already have a built-in Face Unlock feature, but this patent is a more advanced version of the technology as it adds a "liveness" feature.
Its previous Face Unlock was criticized in 2011 after security experts said it could be bypassed by holding static photos up to the phone or tablet's camera.
Android was updated in July 2012 to add a "liveness" check that had the user blink while using Face Unlock to prove they were real, but this could also be bypassed by using a photo editing trick.
This latest patent will require users to perform specific, predetermined facial expressions, strengthening the security of the feature.
Once the facial expression is scanned, it would then be compared to a photo of the user to confirm the identity.
"The anti-spoofing techniques herein may use facial gestures such as blinks, winks and other gestures that may be performed within the confines of a human face," the patent said.
"The device may detect facial gestures associated with various facial features."
Such expressions include blinking or winking, using the mouth area to frown, smile or show a tongue, wrinkling the nose, forehead or raising one or both eyebrows.
The patent said there would be a small margin of error but the user's expression will have to match the original photo as closely as possible for it to be unlocked.