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Last updated: May 8, 2023

How to Keep Your Car Key Fob From Being Hacked

Stop thieves from accessing your keyless-entry car.

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There was a time when a car that could unlock automatically when its driver approached was the stuff of science fiction. Today, it’s a reality, and keyless-entry cars are increasingly popular. This convenient feature allows drivers to unlock and even start their cars without fumbling in their bags or pockets for the keys.

Unfortunately, this convenience makes keyless-entry vehicles a target for criminals, who have developed techniques to hack key fobs and steal cars. Read on to learn who’s at risk and how you can protect your vehicle from keyless car theft.

How to Stop Thieves From Hacking Your Key Fob

Block Hackers’ Signals

The cheapest and most convenient way to stop thieves from hacking your key fob is to stop hackers’ signals from reaching your key fob in the first place. Put your keys in a Faraday bag, a metal-lined pouch that blocks electromagnetic fields like radio signals and electrical currents. The metal lining blocks thieves from picking up your key’s signal and using it to steal your vehicle.1 The bags are portable, effective, and cheap.

A wide variety of online retailers like Amazon sell Faraday bag devices for $10 or less. Many hardware and electronics stores sell Faraday bags as well.

If you choose not to use a Faraday bag, you’ll need to take extra steps to protect your key fob. When you’re at home, keep your keys as far away from your car, doors, and windows as possible. That makes it harder for thieves to pick up your key fob’s signal from outside your house.


Even if you don’t use a Faraday bag, you can add another layer of security by keeping your key fobs in a sealed metal box like a safe when at home.

Reprogram Your Keys

One benefit of electronic keys is that you can reprogram them, which negates the need to change the locks on your car. Take this step after you buy the car to make sure no one who might have a spare key can use it.

For security reasons, vehicle manufacturers only license the software for reprogramming key fobs to dealerships and locksmiths. The dealership or locksmith will ask you to show proof of ownership and registration, and will need access to your vehicle and key fobs simultaneously. Depending on the type of car you drive, a specialist will use one of two forms of key programming, either OBD2 or EEPROM, to create a new “password” frequency between your key fob and car. Though this process only takes a few minutes, it can cost between $200 to 400 per key fob.2

If you suspect that your key fob has been hacked, you can reprogram your keys to ensure anyone who captured their signal can’t use them. Considering the cost of reprogramming, though, it’s much more affordable to keep your keys in Faraday bags in the first place. Keep track of the whereabouts of your key fobs, and go to your dealership or a locksmith to deactivate any lost or stolen ones.

What Is Keyless Car Theft?

Keyless car theft is a form of auto theft that targets keyless entry and ignition vehicles through one of two strategies.

  • Cloning: Hackers use flaws in key fobs’ encryption to get access. They use RFID transmitters to copy the radio signals that particular key fobs produce, making “clones” they can use to steal cars.
  • Signal boosting: Signal boosting, also called a relay attack, typically requires a pair of thieves working together. One thief stands near a key fob’s location to capture its electronic signal, then uses a device called a keyless repeater to transmit the signal to their accomplice. The other thief waits near the car and uses the transmitted key signal to unlock it. In some cases, a single thief will use a signal amplification device to increase a key fob’s range, which fools the car into thinking its key is nearby when it isn’t.3

What Cars Are at Risk of Keyless Car Theft?

Cars with keyless entry systems (meaning they can unlock doors and start ignitions when someone holding the key fob approaches the vehicle) are vulnerable to keyless theft. If you need to push a button on your car key remote to unlock and lock the vehicle, you are not at risk of your key fob being hacked.

British insurance company Aviva reports receiving twice as many auto insurance claims for thefts of keyless entry cars versus vehicles without keyless entry.4 Despite this, keyless cars are increasingly common. As of March 2023, the global automotive keyless entry system market is worth $1.57 billion, and market research authority The Business Research Company forecasts it will grow to 2.48 billion by 2027.5

How Close Do Thieves Need to Get to Hack My Car Keys?

You may think of hacking as something that happens over the internet, like phishing scams and other crimes that can occur at great distances. Key fob hacking is different. Thieves only need to come within a few yards of your key fob to capture its signal. Stealing the signal can take less than a minute, which means it’s important to protect your key fob at all times.

Minimizing the Risks of Keyless Car Theft

Even if thieves hack your key fob, you can still take action to minimize the risk of car theft.

  • Use anti-theft devices. Use a physical theft deterrent like a steering wheel lock so a thief can’t drive off with your car even if they’re able to unlock it.
  • Park defensively. You may be familiar with defensive driving, a set of driving techniques designed to avoid accidents. Apply that same preventative mindset to parking. Park in a private garage or another place where it’s harder for thieves to access your vehicle. If your parking spot doesn’t have security cameras already, consider installing some to monitor your vehicle.
  • Never store valuables, spare keys, or garage door openers in your car. If thieves do unlock or even steal your car, you don’t want them to be able to enter your home as well.
  • Make sure you have car insurance that covers theft. While there’s no state that requires comprehensive coverage, we recommend it because it’s the only form of auto insurance that covers theft, including keyless car theft.


A theft claim will only pay out the actual cash value (ACV) of your vehicle. Since new cars begin to depreciate in value as soon as you drive off the lot, that value may be less than what you owe on your lease or loan. That’s why most loan/lease providers require you to buy gap insurance, which covers the difference between your car’s ACV and your remaining balance.


Keyless-entry cars offer drivers a convenient method for unlocking their cars without taking out their keys. Unfortunately, thieves have learned to take advantage of this high-tech feature and can hack key fobs to steal vehicles.

Take steps to protect your key fob from hackers to minimize the risks of auto burglary and car theft. The simplest, most effective method is to place your key fob in a Faraday bag whenever you exit your car. Protect yourself further by parking defensively, using anti-theft devices, and ensuring that you’re up to date with comprehensive coverage.

Frequently Asked Questions

Does a fridge stop keyless entry?

Although fridges and microwaves can stop keyless entry fobs from being hacked, they can also severely damage your key fobs. Store your keys in a Faraday bag and/or safe rather than in the fridge or microwave.

Will my car shut off if I walk away with the key fob?

No, your car will not shut off automatically if you walk away with the key fob. Rather, you’ll need to turn off the engine and lock your vehicle whenever you’re not in the car.

What are the signs of low battery in a key fob?

The main sign that your key fob has a low battery is reduced range, meaning you need to get closer to the vehicle for it to unlock. Other signs are that the buttons and lights on the fob and the vehicle’s push-button ignition work inconsistently or not at all.


  1. Do Faraday Bags or signal blockers for keyless cars work? Ask The Car Expert. (2023).

  2. Everything You Need to Know About Car Key Programming. Carkey Action. (2023).

  3. Keyless entry systems and the ‘Relay Attack’. Thatcham Research. (2023).

  4. Got a car with keyless technology? It’s twice as likely to be stolen: Insurer reveals changing face of motor theft as brazen criminals shift tactics. This is Money. (2022, Nov 30).

  5. Automotive Keyless Entry System Global Market Report 2023. Research and Markets. (2023, Mar).