The low-tech strategy is being recommended as a counter against a high-tech version of car theft, in which thieves use special equipment to pick up the signal from your key fob to access your parked car. Called a “relay attack,” this method of theft has been reported around the world.
“It’s an incredibly common occurrence and the easiest way to gain entry to or otherwise steal a high-end car,” Campbell Murray, technical director of cybersecurity at BlackBerry, said in an email. “A quick search on YouTube for ‘car stolen key amplification’ or ‘car key relay’ will return hundreds of CCTV clips where the attack is being undertaken.”
Wrapping your key in aluminum foil will protect against that kind of attack. The question, though, is whether having to unwrap your keys like cold leftovers every time you want to use them is worth the security you gain.
The experts we asked said it’s honestly probably not worth the hassle. For one, while there are many documented relay attacks, it’s not clear how many of the country’s estimated 765,484 motor vehicle thefts are committed this way. That’s because it leaves almost no trace, unlike a smashed window, said Michael Calkins, manager of technical services at AAA. But we do know that there are some people who are at a higher risk than others. People with high-end cars are bigger targets, Calkins said. Cars that have valuables in plain sight on the seat are also a target.
But not every type of car with a key fob is affected equally. For the type of attack described by the Free Press, it would have to be a fob that not only unlocks the car but is also used to start it. A normal keyless entry system only sends a signal when the button’s pressed, and so is not vulnerable to the type of relay attack described by the Free Press. (Blackberry also demonstrated how it’s possible to reproduce the signal of that sort of key fob, but it requires someone to be waiting for you to push your fob to duplicate your signal.)
Experts said that even those still worried about falling prey to this kind of attack are better off investing in a pouch or bag that blocks electromagnetic signals, rather than pillaging their kitchen drawers. While it may be annoying to pull your keys out of their pouch each time you get to your car, it would certainly be less annoying than wrapping and unwrapping your keys.
Calkins suggested that the best way to protect your car has more to do with common sense than your access to a roll of foil. When possible, he said, park your car in a garage. He also warned against online advice that suggests storing your keys in your freezer or microwave, as either could damage the electronics in your keys. Those who are really worried can always take the battery out of their fob and use the physical key concealed inside. That, too, compromises convenience but may increase your peace of mind.
Overall, however, the consensus seems to be that while you can do more to protect your keys, it’s not something you must do.