Should I store my car keys in a Faraday box? Perhaps. With the advent of keyless entry, you can unlock your car just by approaching it, which is particularly handy when you’re carrying shopping and need to access the trunk.

However, depending on electromagnetic signals for locking and unlocking your vehicle—rather than using a traditional key—means there’s a risk. With the right technology, someone could intercept and misuse that digital communication.

In the UK, there were almost 130,000 vehicles stolen from April 2023 to March 2024. Furthermore, more than half of these incidents involved thieves manipulating the signal from the car key without ever having physical access to it.

This problem mainly affects vehicles with passive keyless entry systems, which enable you to unlock the door just by being within a certain range of the car without pressing any buttons. These systems work by emitting a signal detectable by nearby cars.

The distance at which this works varies by manufacturer, but theoretically, if your keys are inside the house and your car is in the driveway, the keys and the car are far enough apart that no signal should reach them.

Nevertheless, thieves may use devices to extend the key’s signal range, executing what’s known as a relay attack, which typically involves multiple devices.

The first thief situates themselves outside the house within range of the keys and captures the signal to relay it to a second accomplice positioned next to your vehicle.

They utilize their devices to capture the exact data contained within the signal, which is then relayed to their accomplice with a second device near your car. The vehicle recognizes the key-specific signals and unlocks as if the key were present.

To prevent this scenario, apart from switching to a lower-tech vehicle, ensure that your key doesn’t emit any signals when you don’t need to unlock your car.

Some manufacturers are offering “sleeping fobs” in newer models that employ motion-sensor technology to halt signal transmission when the key is not likely to be needed.

Additionally, some companies are developing keys that operate on bandwidths much more difficult to relay.

One day, we may eliminate keys entirely, replacing them with biometric technologies like fingerprint or facial recognition for car access.

For now, if your vehicle employs keyless entry and a sleep mode isn’t available, it’s advisable to find alternative ways to block the signal.

This is where a Faraday box or pouch becomes useful. These containers are lined with conductive material to prevent signals from entering or exiting.

You might also wrap the key in aluminum foil or store it in a microwave or refrigerator—just ensure the latter is turned off.

This article addresses the query (submitted by Radhika Bhatia): “Should I keep my car keys in a Faraday box?”

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