Many people wrap their car keys in foil to minimize the chances of their car getting stolen. Foil around the car key fob limits the distance the signal travels. If there are prospective car thieves around looking to intercept the signal, the foil can stop the signal from traveling too far. 

Key fobs are practical and make life easy when you want to access your car. But technology and advanced features sometimes come with threats. Car owners face a growing threat from something known as relay attacks. These attacks involve thieves using sophisticated gadgets to intercept and mimic the signal from your keyless entry fob to gain unauthorized access to your vehicle. 

Surprisingly, a simple piece of aluminum foil could be an effective way to protect your car from such high-tech thievery.

What are Relay Attacks?

Let’s be honest: keyless entry systems on cars are convenient, quick, and practical. You can unlock and start your car from afar, while the key fob remains in your pocket. In some cars, the key fob opens the trunk, which is great when you’re carrying groceries and bags. 

But this convenience also opens up vulnerabilities. Thieves are developing new skills to stay one step ahead of technology. They use devices called relay amplifiers and relay transmitters to extend the signal of your key fob from inside your home to your car parked outside. This method doesn’t require breaking in physically; it’s all about intercepting radio frequency identification in the air.

If they are around when you use your key fob, they can intercept the fob’s signal, copy it, and then gain access to your car without the need for the original key fob. 

How Fob in Foil Helps

The concept of using aluminum foil to protect your car keys is based on the idea of a Faraday cage. This cage blocks electromagnetic fields and prevents signals from your key fob from getting stolen by thieves’ devices. 

When you wrap your keys in foil, you effectively mute its communication abilities. The signal’s range is much shorter and can’t be intercepted easily. 

The Benefits of Using Foil

Aluminum foil is cheap and we all have it at home. 


Aluminum foil is affordable and available. We all have foil in our kitchen. 


It blocks electromagnetic fields when wrapped properly, which means it jams the signal and prospective thieves can’t intercept it. 


You don’t need any technical know-how. Simply wrap the fob, and you’re done. 

Convenience vs. Security

Wrapping your keys in foil is effective but can be impractical. There is the inconvenience of unwrapping and rewrapping the key every time you need to use your car. Also, the foil needs to be completely intact without any tears or gaps to be effective, which means you need to regularly replace it. Again, tin foil is inexpensive but it can get annoying after a while. 

Alternatives to Foil

For those looking for a more durable and convenient solution, Faraday bags are an excellent alternative. These are small pouches designed to shield their contents from electromagnetic fields. They are more durable, stylish, and user-friendly compared to foil. They are more expensive than regular tin foil but ultimately they offer a good balance between security and convenience.

Making the Right Choice

If you are concerned about your car’s safety, there are many ways you can protect it. 

Aside from the simple foil or the Faraday bag, there are other options as well. 

You can invest in a GPS tracking system and have it installed in your car. These systems can provide real-time location updates and are really helpful to law enforcement in case your car gets stolen as it sends a signal of its location. 

Some car owners choose to mark parts of their car with an invisible ink pen or use microdots with the VIN (Vehicle Identification Number) to help police identify parts of the car if stolen. 

Protect Your Car From Theft

It makes absolute sense that you would want to protect your car. 

Before you invest in ways to protect your car from theft, consider your environment, the frequency of car use, and your security priorities. If you live in a high-theft area or you prioritize security over convenience, the solutions we have offered are effective and affordable. 

Wrapping your car keys with foil adds an extra layer of security to your vehicle and discourages high-tech thieves. Remember, in the battle against car theft, every little bit helps! If you need professional assistance, you can always reach out to a car locksmith.