person holding a car key fob
Julie Hambleton
Julie Hambleton
January 25, 2024 ·  4 min read

Warning: Why You Might Want to Wrap Your Car Key Fob in Aluminum Foil

In the past, we’ve written articles warning about living room televisions listening to your family’s conversations and cells phones recording your voice when you least expect it. Believe it or not, that’s not the only thing listening but it’s not what you would expect. Your car is also listening… for an electronic signal. Do you have a newer car model with a hands-free fob car entry system? While it’s convenient not to have to push any buttons or insert any keys when you’re close to your vehicle, the rate of car thefts is rising.

According to CBC, this newer crime is known as “electronic car theft.”[1] Car thieves are even creating simple devices that boost the wireless signal between fobs and cars – without setting off any alarms! By doing this, criminals can open (and sometimes start) a car long before owners reach their rides.

But Aren’t My Car and Fob Codes Unique to Each Other?

Yes, they are; the computer chip codes in your car and fob are designed so that when the signals in both match, the vehicle opens. Here are two examples of how car thieves of hackers can carry out an electronic car theft:

  1. Researchers from the University of Birmingham and Raboud University in the Netherlands conducted an experiment to test how easy it would be to boost a signal and break into a car. If they could intercept a car signal just twice, the possible code combinations drop from billions to ~200,000. At that point, a computer can decipher the code in 30 minutes and open the car.
    In theory, someone could sit on your street collecting wireless signals as people run in and out of their vehicles. After another few hours, they could figure out the codes and steal numerous cars overnight. Although this isn’t likely, the risk still exists. But there’s one much more likely way you become a victim of electronic car theft…
  2. Modern cars that come with “always-on” fobs are designed to stay locked until it comes within a foot. Comforting, right? Yes and no. New York Times’ Nick Bilton experienced this himself on his own street. After numerous cars on his street were stolen (including his, three times in one month), Bilton finally caught the teenagers responsible along with their mysterious black box.[3]
    He later learned that the black box was a power amplifier that boosts the fob signal to open the car from up to 300 feet away! What’s so scary is that anyone can purchase these power amplifiers for less than $100 and as cheap as $17!

One solution to combat the rise of electronic car thefts is for car manufacturers to make a key fob that requires drivers to activate it when they’re ready to go. Of course, this sacrifices the convenience that everyone loves. And in today’s day and age, convenience is king.

Authorities Worldwide Are Warning Car Owners to Take Action

If you want to take precautions to prevent electronic car theft, there are some unconventional solutions authorities and other experts suggest.[2,4]

Freeze Your Fob

Before doing this, make sure to check with the manufacturer that it’s safe to freeze your key fob. If it’s OK, the metal barrier will block the fob’s signal and protect it from power amplifiers.

Put It in a Microwave Oven

Keeping it off, of course, the metal in this kitchen appliance will also protect your car from being stolen. The signal boosters are not sophisticated enough to pick up your key fob’s signal when it’s protected by materials in microwave ovens.

Wrap the Fob in Aluminum Foil

Although we don’t suggest heating and cooking with aluminum foil, we are OK with using it to protect your family’s car and its contents! It’s an inexpensive way to protect your vehicle, however, experts are warning to wrap it completely (ideally with a few layers) to avoid any openings that will risk a signal connection.

Other Ways to Prevent Electronic Car Theft

  • Store your key fob in metal coffee cans
  • Get a small signal-blocking bag to protect your key fob

Until car companies come up with a way to protect car and key fob signals even more, we hope these solutions bring you and your family safety and comfort! If you know anyone who has been a victim of electronic car theft, feel free to send this article their way! Better safe than sorry.


  1. How thieves use electronic devices to steal cars.” CBC News. Sarah Bridge.
  2. Why you might want to wrap your car key fob in foil.” USA Today. Phoebe Wall Howard.