Terrified by the thought of identity-thieving cybercriminals, or over-zealous NSA agents snooping on your private data? Have a tinfoil hat for each DEFCON level? Then this app, which can (probably) tell you if you're being spied on by the government or data thieves, is totally for you.
SnoopSnitch is an app for rooted Android devices that analyses your mobile radio traffic to tell if someone is listening in on your phone conversations or tracking your location. Unlike standard antivirus apps, which are designed to combat software intrusions or steal personal info, SnoopSnitch picks up on things like fake mobile base stations or SS7 exploits. As such, it's probably ideally suited to evading surveillance from local government agencies.
The app was written by German outfit Security Research Labs, and is free and available on the Play Store. Unfortunately, you'll need a rooted Android device running a Qualcomm chipset to take advantage. Of course, you could also just burn all your devices and go and live in a wilderness treehouse. [SnoopSnitch via Android Community]