How to Prevent Keyless Car Theft

By Colin Aulds

Car theft is something that has been observed since the invention of the automobile. In the times when cars had door locks and ignitions with a mechanical key, people found ways to pick the lock and hot-wire the car.

With the advancement in technology, electronic locks were introduced, and now cars have a central computer that is locked with an electronic key.

This is one of the best ways to prevent thieves from stealing your car. However, as with every technology, thieves have found a way around this security measure and have started using devices called code grabbers to perform what is called a SERA (or 'Signal Extender Relay Attack').

The thief utilizes a device that looks for the signal emitting from your key fob and amplifies it, allowing the thief to unlock your car and start the ignition. 

SERA attacks have become more common everyday and the cases of theft have been increasing considerably. People are often perplexed by the question of how to prevent keyless car theft?

In this article, we will look at something called a Faraday bag, which is one of the most effective products on at the market at preventing SERA attacks. 

Why Are Car Thefts Increasing?

Police departments around the world are seeing a huge increase in car theft in recent years.

These thefts have left police departments baffled because most of these cars were locked with an electronic locking system which is one of the safest auto security systems available.

After investigating, you will find many videos showing thieves using a device to open the lock of the car and stealing it without tampering with the vehicle directly. So, what is this device that is being used to steal these cars? 

 This device that the thieves have been using is called a key fob code grabber.

Thieves have become tech-savvy and have started using this device to catch the radio frequency of the key fob, cloning it, and then using the newly made duplicate signal to open the door of the cars and drive off. You can watch a video of it happening right here!

Modern car key fobs work with the help of electro-magnetic signals. When the car key is near the car, there is a radio frequency between the car and the key fob.

When the user presses the unlock button on the remote of the car, the doors opens since the car sees the signal. The only way in which this theft can be stopped is by using an RFID blocking bag, also called a Faraday bag

What Is A Signal Killer Faraday Bag?

The Signal Killer Faraday Bag is designed on the basis of the Faraday Cage. The Faraday Cage was developed by the famous scientist Michael Faraday.

The cage is made of conductors that do not let any other electric signal or wave enter. This principle is also used in building airplanes; the planes are designed in such a way that if struck by lightning the electrical force cannot enter the inside of the airplane.

The Signal Killer Faraday bag functions in much the same way. It blocks out all the waves that are entering or exiting and spreads them around but does not let them pass.

So anything that is kept inside the bag cannot be accessed by outside electric or magnetic waves and vice versa.

Faraday bags have been used by the military and police for ages to protect technological evidence such as phones, laptops, smartwatches, or other hardware that has important digital data inside.

This technology is now being used by the public since data and car thefts are increasing considerably.

Preventing Keyless Car Theft With a Faraday Bag

Now the question is, how can you prevent your car from being stolen by using faraday bag?

As we explained above, the thieves are using code grabbers to extract signals from the car key fobs and duplicate or extend them so that the car system gets tricked and the car door unlocks easily.

With a Billfodl Faraday Bag, the signals from the car keys will get blocked, so the radio frequency of your car keys will never reach the thief's device. This will save your car from being stolen. 

Because most of these thefts are happening at home, it is best to keep the Signal Killer bag where ever you normally keep your keys.

Just get into the habit of dropping your keys into the bag as you come in the door. Then you no longer have to worry about your car getting stolen in the middle of the night. You can buy one of our bags by clicking the 'Add to Cart' button below.

Small Faraday Bag
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Other Uses For Faraday Bags

A Faraday bag from Billfodl may help protect your car from getting stolen, but what else can it do? Are there any other advantages to owning a Faraday bag? Yes! These bags are really useful in many other ways; here are just a few of them: 

1. Prevention of Phone Tracking

The Faraday bag can also be used to prevent your phone from being tracked. We all use smartphones with GPS technology and Wi-Fi. This bag blocks your cell phone from sending out any information about you while it is in the bag. The only drawback is that your mobile network will also get cut off and hence you will need to take your phone out if you need other kinds of connectivity.

2. Safeguarding Personal Data from RFID Swiping

Credit cards are one of the most common forms of payment and most of us who travel must bring our passport along with us.

However, both of these items utilize chips that hold very important personal and financial information about us, which when leaked can cause serious problems for us, such as identity theft.

A common practice of thieves the world over is to use an RFID reader to swipe information off of your cards or passport by merely waving it close to your body and hoping they get a hit.

It is, therefore, important for all of us to consider these kinds of attacks in places like airports and foreign countries and use a faraday bag to prevent them.

3. Save Laptops and Other Devices From Being Hacked

When we are in public places, our laptops and other smart devices are at the highest risk of being hacked. Hence, it is important to keep your devices in the Faraday bag when you are not using them.

This will help in protecting them from hackers who want to glean your personal information from them or install malicious software on them to exploit later on. 


As we have noted, it has become easy for the thieves and hackers to get a hold of your car key’s signal and steal your car without you even noticing it.

Additionally, thieves have their eye on your credit cards and passports, as well as your personal electronic devices. For this reason, everyone should consider investing in a signal blocking Faraday bag.

You can find those right here on our site. We have two sizes included in the bundle: one for your keys and another for your electronic devices like your phone and tablets. 

Faraday Bag Bundle
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1 Response


July 01, 2019

Amazing blog post and very nicely explained prevents our cars from theft. Thanks for sharing this is the really helpful blog for everyone.

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