How a Microwave Oven Can Protect Your Car Key from a Relay Attack

Vehicle technology is not the only thing advancing: theft methods are evolving too. Breaking locks or hot-wiring are no longer necessary to steal a modern car. A simpler, less noticeable technique can unlock and start vehicles fitted with a remote electronic key.

How a relay attack works

Known as a relay attack, this method picks up the electronic signal emitted by a key from a distance. All that is required is for the signal to be boosted and sent to a second device positioned close to the vehicle.

The car’s sensors then “think” the key is nearby, automatically unlocking the doors and enabling the ignition. Because it happens quickly and discreetly, the theft can be virtually undetectable.

Can a microwave oven block car key signals?

A curious solution has emerged in response to this issue: the microwave oven. Its metal construction forms a Faraday cage, blocking electromagnetic signals from entering or leaving. If the car key is placed inside the microwave and the door is shut, its signal is isolated, preventing external equipment from intercepting or amplifying it.

Faraday pouches and other safer options

For people seeking a safer alternative, experts advise using specially shielded bags or boxes, known as Faraday pouches or Faraday boxes.

These affordable, practical accessories block the remote key signal in much the same way as a microwave oven, without putting the equipment at risk. Other straightforward options include wrapping the key fob in aluminium foil or storing it in a metal container. This may also help anyone who never knows where they have put their keys.