Disclosed is an apparatus and method for a mobile device to provide increased security that is less obtrusive. A mobile device includes a display device, a user interface, and a processor. The processor may be configured to execute instructions to: implement a monitoring function to monitor the operation of the mobile device and to implement a plurality of monitor functions; and implement an authentication process to compare the plurality of monitor functions to a time period to determine an authentication value, wherein if the authentication value exceeds a threshold, a lock screen is implemented on the display device, and a user is required to enter a valid passcode through the user interface for authentication. Each monitor function may be associated with a pre-determined weight such that different monitor functions are given different priorities.