A wireless mobile phone is equipped to operate in an unauthenticated and an authenticated mode of operation, depending on whether a user has been authenticated. In one embodiment, the wireless mobile phone includes a finger print reader to enable a user's finger print to be inputted and be used for authentication. In one embodiment, the finger print reader includes a light source and sensors, and having complementary logic to process emitted light reflected off a user's finger into an input finger print. The user is authenticated using the inputted finger print. In one embodiment, the finger print reader is integrated with a power on/off switch, which may be disposed on an end surface, a side surface or a front surface of the body of the phone.