If you looked at Amnesty International's new (and free) Panic Button app for Android, you wouldn't even bat an eyelash. That's precisely the point. It's meant to help human rights activists around the world subtly seek help when things take a turn for the worse, and that's why it's disguised as the most banal mobile utility you could probably think of: the humble calculator app.
The app -- which has been in development for over a year now -- adds, subtracts, multiplies and divides just like you'd expect it to after a bit of onboarding. Hell, the app icon even changes after setup is complete to keep an even lower profile. Invoking its true purpose requires you to wail on a digit key or mash your phone's power button. It's only then that this unassuming number cruncher fires off a distress message and your location to three preset emergency contacts, with further updates to follow every five minutes until your phone runs out of juice.
Clever, no? The app's thoughtful design means you can very quietly reach your closest allies without arousing suspicion, or even removing your phone if your pocket if things are seriously dire. It's under a megabyte in size, too, not to mention dead-simple to set up and compatible with all versions of Android newer than Gingerbread. Oh, and it's open source (you can dig through the source code on GitHub), just in case you want to implement some more specific modifications. Really, there's only one rub here. The Panic Button is a nifty little tool, but it's ultimately useless unless your chosen contacts are actually in a position to help. Amnesty International insists that the Panic Button should be but a component of a broader contingency plan for activists who may cross paths with jackbooted thugs. Choose your confidants wisely, dear friends, and be ready.