Now that it’s been over a year since the Snowden leaks, you might’ve thought that all of the insane NSA revelations had been revealed. Not so! Foreign Policy just published a fascinating and exhaustive list of every patent ever awarded to the spy agency. And one of its latest inventions is all about your SIM card. Last July, the Patent and Trademark Office issued the NSA a patent for a “device for and method of detecting sim card removal and reinsertion.” That invention is exactly what it sounds like. The NSA can know—or at least they patented a method of knowing—when someone swaps a SIM card. This is obviously handy for spotting would be terrorists who constantly switch phones to evade detection, but based on the NSA’s super spotty track record, there’s certainly a chance they’re using it on American citizens, too. But hey, that’s hardly the creepiest patent on the (pretty long) list.