Abstract: This is described a method of access control for a mobile computing device having a touch-screen, the method comprising: receiving a signal indicating an input applied to the touch-screen; matching the signal against a library of signal characteristics to identify a user of the mobile computing device from a group of users of the mobile computing device; receiving an additional input to the mobile computing device; using both the signal and the additional input to authenticate the user; and if authenticated, allowing access to the mobile computing device in accordance with configuration data for the authenticated user.