RollJam is a $30 device that can unlock just about any car door or garage that uses wireless unlocking technology. Car and garage door keys often operate on what are called “rolling codes” - codes that change every time you press the lock or unlock button on your wireless key, and expire as soon as they’re used. Because the security code constantly changes, these systems were considered relatively secure. At least until Samy Kamkar, the hacker and security researcher behind RollJam, created a simple way to hack the system.

Image: Samy Kamkar via Motherboard. Image 1.Image: Samy Kamkar via Motherboard

The RollJam is a small device roughly the size of a car key that can be hidden under a car or near a garage door. When the owner uses their wireless key to open their garage or unlock their car, the RollJam blocks the signal and records it, forcing the owner to press the button again. At this point, RollJam jams the signal again and then replays the first code it recorded, unlocking the car. To the owner, nothing out of the ordinary has happened - they just had to press the button twice. But in reality, the RollJam has a valid, unused rolling code. If it’s left on say, the bottom of your car, it will always have the latest code to unlock your vehicle.

Kamkar has tested the device on a variety of cars, such as Cadillac, Ford, Toyota, Lotus, Volkswagen, Nissan, and Chrysler. The device also works with “virtually every garage door” using radio signals. Kemkar says the reason she created RollJam wasn’t to steal cars but to give car manufacturers and the companies that make these vulnerable chips a wake-up call.

Cover image: Samy Kamkar via Motherboard