PassApp is a novel recognition-based graphical password. It utilizes users' installed apps on their mobile devices as passwords to protect the devices from being illegally accessed.
16 app icons will show on your screen when you try to unlock your mobile device. Recognize and correctly tap 4 apps you previously installed on your device and then you can successfully unlock your device.
From all of your installed apps, PassApp randomly chooses 4 installed apps as your password in the current challenge panel. That is to say, your installed apps act as your passwords.
Decoy apps are the apps that are not installed on the user's mobile device. PassApp selects decoy apps from the decoy app server and builds a decoy app library for every user based on his/her installed apps. This machanism aims at making decoy apps more similar to installed apps to confuse illegal intruders.