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Comment by rahimnathwani | Hacker News Reader

This is a confusing article. I'm not sure what 'scrambling' means here:

  Keyless repeaters and signal amplifiers scramble the signal from remote key fobs inside people's homes, enabling criminals to unlock cars.

And it talks about banning 'signal jammers'. How is a signal jammer useful for stealing a car? Wouldn't a signal jammer prevent someone from unlocking a car?

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Yes, it would stop somebody's key from working, and that's the entire point, because most key fobs work on rolling ciphers, and if you block one, you can reuse it. Typically the fob will allow like 10 or so presses. It depends on the model before you're forced to re pair to the car. But by jamming it and capturing what it sent, you can then use that to get into the car.

You can sit around a car park with a jammer and jam the signal as people walk away from their cars - some people don't notice that their attempt to lock the car just didn't do anything.

I don't know how that is still a problem. I drive a 2019 Renault, and it has both rolling codes and it locks automatically if it doesn't detect the key anymore.

I've never seen a car that would lock automatically if you've been driving it and just got outside and never locked it. Maybe that's a french car thing?

The jammer prevents the car from hearing the transmitted un/locking signals while the jammer themselves collects and repeats it later.

That, or to prevent the tracker in more expensive cars from doing their job. In mainland Europe, some high end cars need to be fitted with a GPS tracker for insurance. Thieves will try to jam GPS to those trackers until they're: A) figured out how to disable/remove it, B) fled the country.

Not just high end and insurance. In EU 100% of new cars have GPS installed. This is used for intelligent speed assist and eCall that are now mandatory.

It seems challenging to jam a transmission from being received, whilst capturing that same transmission.

If you place a device with a high-gain directional receiver pointed toward the fob, and a high-power transmitter pointed toward the car, wouldn’t that work?

> How is a signal jammer useful for stealing a car?

I can't vouch for UK in particular, but generally having some sort of tracker (level x security system) is mandatory to insure more expensive/exotic cars. A signal jammer prevents the tracker from calling home and, well, the stolen car being tracked before the tracker is found, disconnected and destroyed.

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