Earlier to unlock Chromebook user uses their Google account password or they paired their smartphones to do so, but now there's another option, users can now also unlock their Chromebook using a simple personal identification number (PIN).
Google developer François Beaufort outlined how to use this new option in Google+ post:
" All you have to do is enable the flag chrome://flags/#quick-unlock-pin, restart Chrome, and go to Chrome Material Design settings page for now to set up your Lock Screen PIN in the new "Screen Lock" section. When it's done, lock your screen with + L and enjoy the new unlock experience! "
He also stated that this feature is currently experimental, but it should make things easy for users.
As per report from OMG! Chrome suggests, the users can now input a 4-digit PIN rather than using their entire Google password and this feature is part of the latest Canary Build for the operating system.
Keep in mind that this will only be used to unlock the lock screen.