PhoneAuth. An Android application built for additional authentication and user verification. The app when installed on the user’s mobile, automatically performs a handshake with a pre-registered computer as and when it comes into Bluetooth range and identifies itself using the IMEI and MAC of the device. Thus, it can uniquely identify the user using his/her mobile device. This is built as a layer on top of the usual username-password protection system (using the Linux PAM APIs). This process happens periodically which means that if the user is not in the vicinity of the computer, it is immediately locked.