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  • Abbie Jones

How a Car Key Fob Works

woman holding car key fob

Fob car keys are becoming more popular and common as they're often being used for cars with keyless entry, which is 80% of new cars in the UK. So, due to the popularity of keyless entry systems for cars and the rise of fob car keys in the UK, we thought we'd tell you everything there is to know about fob keys in this Keytek® Auto Locksmith blog!

What is a Fob Car Key?

A fob car key is the small remote-control device that controls a remote keyless entry system for a car. The noise that comes out of your car keys when pressing the button and unlocking the car doors is all from the fob embedded into the key. It contains a short-range radio transmitter to send distinct codes to a receiver unit in the device.

How Do Fob Car Keys Work?

A car key fob is made to be used to secure your car and only give certain people access to your vehicle. They are digital keys that provide remote access, so you don't need to put the key in the car door to open it, as you do with manual locks.

Fob car keys work through their built-in Radio Frequency Identification system. The car itself has its own unique tags that the car key fob also has, so when the button on the fob is pressed, it communicates to the car that has the same tag information which in turn locks or unlocks the car.

How is a Car Key Fob Different to a Standard Key?

Fob car keys differ from standard car keys because they allow a car owner to lock/unlock and start the car with just pushing a button, and not having to do it manually like a traditional car key fob. Fob car keys can also control opening windows, the boot, and can arm/disarm the car alarm, unlike a standard car key.

What Controls the Fob Car Key?

The majority of car fobs use pseudo-random sequence generators to transmit a unique unlock sequence every time it is used that will activate the lock, and ultimately lock and unlock your car doors.

How to Open a Car Door with a Car Key Fob?

Opening a car door with a car fob key is easy! All you have to do is hold the fob in front of the reader, where the fob will then communicate with the reader, indicating that the door should be opened.

Is a Fob Car Key More Secure for your Car?

Having a fob key for your car adds a layer of security to your vehicle. They do this by preventing attackers from accessing a system where they can commit cybercrimes involving your car, including stealing data, locking the system, and demanding a ransom to unlock it, and committing identify fraud. They prevent this as an attacker would need access to the fob, and if a hacker does get access to the system, they need a lot more than compromised credentials.

Car key fob owners need to be wary about relay theft however, where an attacker uses a trick device to fool a vehicle into thinking that it is the key fob that is needed for that car, ultimately locking and unlocking the vehicle for the attacker. The main premise of relay theft is that when one person uses a trick device on the car, another person will stand near the owner's house trying to get the signal from the key fob. Owners can prevent this from happening by investing in a faraday pouch for their key fob, which is designed to shield electronic devices from transmitting or receiving signals.


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