In 2003, Finnish security researcher Tomi Tuominen was attending a security conference in Berlin when a friend's laptop, containing sensitive data, was stolen from his hotel room. The theft was a mystery: The staff of the upscale Alexanderplatz Radisson had no clues to offer, the door showed no signs of forced entry, and the electronic log of the door's keycard lock—a common RFID card reader sold by Vingcard—had recorded no entries other than the hotel staff.

Learn about your ad choices: dovetail.prx.org/ad-choices