Keyless entry – how it works
Keyless car security systems generally consist of two main components – a fob containing a short-range radio transmitter, plus an in-car receiver unit. The fob continually transmits a unique ID code, and when it comes within range of the car, the receiver recognises the signal and prepares to unlock the doors. In many models, the driver simply has to take hold of the door handle and the car will automatically open up.
A growing number of new cars are equipped with keyless entry, which is supposed to provide robust defence against thieves. However, after decades of declining car crime stats, the number of vehicle thefts has risen sharply over the past couple of years – and one explanation is that enterprising thieves have worked out how to get around keyless security systems.
Tech-savvy criminals have identified a major weak-point in keyless security systems – the radio link between the transmitter and the receiver. So if your fob is hanging up near the front door of your home, a thief standing outside with a digital amplifier can detect the radio signal emitted by your fob, and relay it to a transmitter held by their accomplice next to your car.
The transmitter sends the relayed signal to the in-car receiver, which thinks it’s you trying to get in - and hey presto, the doors unlock and the thieves can start the engine and drive away. The entire process can be completed in less than 60 seconds, and because it doesn’t involve any forcing of locks or breaking of windows, it’s virtually silent.
How to prevent relay car theft
The most basic safeguard is to store your fob in a safe place far away from your front door. Somewhere near the middle of your property is best - so thieves sneaking around the exterior can’t pick up the radio signal. Better still, store your fob inside a metal box or a faraday pouch - this will block the radio transmissions and make the fob invisible to the thieves’ amplifier.
It’s a good idea to invest in physical security too, like a traditional steering lock or wheel clamp. Or if you own an expensive car that’s likely to attract the attention of professional criminals, consider installing driveway parking posts. But if you do, make sure they don’t use the same remote control system as your car.