AppLocket is new Cydia tweak for lock all apps that are on your iOS device (i.e. iPhone or iPod touch) and blocks them from launching. Well The AppLocket Cydia tweak overrides the Volume Control Buttons functions and allow you to Lock/Unlock apps using combination of press on Volume Controls. Below is more information about new released AppLocket Cydia tweak.
Well the Applocket Cydia tweak is very userfriendly. If you want to unlock the app, you just have to press the volume button up twice and down once and for unlock it you need to press down twice and up once. i guess it is very easy.
As all other Cydia Tweak you need jailbroken iOS device to run AppLocket Cydia tweak. You can get AppLocket Cydia tweak from Cydia Store.