ChipSpace

Warning: Breaking into cars that use keyless entry.

I can see exactly how this can be done, and it cannot be prevented by encryption. I'll paste my analysis below, but suffice to say keep your key fob a goodly distance away from the car, or in an old biscuit tin or aluminium lines pouch.

https://youtu.be/8MrdC2GWqbg?si=q0fzNWbA_H3xMzXI&t=48

Here's my analysis for the technically minded:

My Mazda CX3 had keyless entry. I could get out, close the door and walk away, and the doors would lock. To do that there would have to be some way of detecting the fob was out of range. My guess would be that the car polls the fob "R U There, R U There" and the fob responds with a very low level ACKnowledgement transmission back. If the fob signal is too weak the car rejects or doesn't detect the signal.

The range of the car's RUT poll will be far greater than the fob's ACK. After all, the car has a huge battery and can afford to send a strong signal.

This observation would fit perfectly with the YouTube 2-man scenario. If the fob is on the hall table it gets the RUT polls but the car doesn't hear or accept the ACK. But the relay device does, and retransmits it with a boost. Bingo! The thieves' devices don't need to crack any encryption, just relay RF signal with the right frequency.

Solution, don't leave the fob near the car, even inside the house. Or keep it in a Faraday cage.

I'm not sure how I'd engineer my way around this without reducing the functionality, given the fob has very little power available. The closest would be a very low power vibration/movement detector that knows when the fob is not lying stationary on the hall table, but is moving in a pocket or handbag. At first I thought of using a temperature sensor (fob in pocket) then realised women would carry it in a handbag.

Car thieves are hacking key fobs to quickly and quietly steal vehicles Cars with keyless entry and keyless start are becoming a growing target for thieves.Story: https://cbsaustin.com/news/local/car-thieves-are-hacking-key-fobs-...