Many online sources advise storing your electronic car key fob in a microwave. This would prevent malicious individuals from capturing its signals to unlock the vehicle without breaking in. In reality, this solution is not ideal and can even prove dangerous.
The microwave oven acts as a Faraday cage
As the rate of car thefts continues to rise, the risks associated with vehicles that rely on electronic keys grow ever more pronounced. It must be said that despite appearances, this system does not actually enhance security. Indeed, the signals emitted by these keys can be intercepted and copied. To do so, criminals typically use a radiofrequency power amplifier (RF amplifier), a device that is fairly easy to obtain. This device enables them to capture the vehicle’s FOB code remotely and thus, to duplicate the vehicle’s key.
These thefts follow a classic two-person operation. The first person positions themselves near the residence (doors or windows) where the key is located, carrying the RF amplifier. The second person stations near the vehicle, ready to receive the data that will unlock and start it quickly. A variant of this type of theft without breaking in involves a signal jammer, which prevents the owners from locking their vehicle, thereby facilitating access to the cabin.
One of the solutions often proposed to prevent piracy is to place the vehicle key inside a microwave oven. The appliance then acts as a Faraday cage, blocking both incoming and outgoing signals.
Other, far more effective solutions
However, the microwave is not a perfect solution. As explained by the 3D Autokeys platform in a 2022 article, this idea can prove counterproductive, even dangerous. Leaving the key inside the appliance could cause a fire when it is turned on. To a lesser degree of severity, it can also lead to damage to the key and/or the oven. Another, much less cumbersome option exists: using a metal box. Nevertheless, one must ensure that this box has no holes that would allow signals to pass through.
It is also possible to acquire a “Faraday pouch” that allows you to store your car key but also your smartphone and other sensitive items such as credit cards. A wide range of products of this type is available in various formats. However, it is necessary to avoid storing these pouches near the doors and windows of the home due to potential variations in the signal-blocking capacity.
