how can someone copy car key signal

[StBeau]

Copying a car key signal, a process often referred to as "cloning," is technically possible but heavily dependent on the type of key and the security technology it uses. The ease of this process ranges from simple for older, traditional keys to extremely difficult for modern, encrypted ones.

The primary risk comes from relay attacks targeting Passive Keyless Entry and Start (PKES) systems. Thieves use devices to amplify the signal from your key fob (e.g., from inside your house) to your car, tricking it into thinking the key is nearby. True signal copying, where the key's code is intercepted and replicated, is more common with older, non-encrypted systems.

Here’s a breakdown of key types and their vulnerability:

Key Type	Technology	Vulnerability to Signal Copying	Common Theft Method
Traditional Metal Key	Physical cut	High (if key is physically stolen)	Physical theft, impressioning
Basic Remote/Transponder Key	Fixed radio code	Moderate to High	Code grabbing devices
Rolling Code/Security+ Fob	Changes code with each use	Low	Typically requires physical access to fob
Proximity (PKES) Fob	Encrypted, two-way communication	Very Low (to direct copying)	Relay Attack (amplification, not copying)

To protect your vehicle, focus on prevention. For key fobs, a Faraday pouch or box can block signals when not in use, preventing relay attacks. Avoid leaving key fobs near doors or windows. For older cars, consider upgrading the security system. If you lose a key, have the dealership deprogram the lost one from the car's computer to prevent misuse. The best defense is understanding that while direct copying is complex, the methods thieves use to exploit keyless systems are more about signal relay than cloning.

[StAmelia]

Honestly, it's scary how easy it can be with the right, cheap gear you can find online. They just need to get close to your pocket or purse with a little receiver. It's not really "copying" like a photocopier; it's more like they're eavesdropping on the signal your fob sends when you press the button or when the car "pings" it. For keyless entry cars, they use two devices—one by the car door and one near your key—to extend the signal. It's a real problem. My advice? Get a signal-blocking pouch for your fob. It's a simple fix that gives you peace of mind.

[McAugust]

As a technology, it involves intercepting the radio frequency signal transmitted by the key fob. With older, basic fobs, a device can capture the fixed code when you lock or unlock the car. This code can then be replayed to the vehicle. Modern systems use rolling codes that change with each use, making simple replay attacks ineffective. The greater threat today is the relay attack, which exploits the convenience of keyless systems by amplifying the fob's passive signal, not by copying its digital identity. The core vulnerability lies in the wireless communication protocol itself.

[Perry]

I think people watch too many spy movies. For the average person, copying a modern car key isn't something you can do with an app. It requires specialized equipment and technical knowledge. The real risk isn't some master hacker; it's organized crime rings using these relay boxes. They're the ones with the tools and the know-how. The rest of us just need to be smart: don't leave your fob in the car, and if you have a push-to-start model, that little metal key blade inside the fob is your last line of defense—use it to lock the glovebox.