3 ms·
Have the key fob beep or buzz when it gets used, along with a panic button that the user could hit on the fob to force the car off and set off the alarm. To de
by derekp7 12y ago
Have the key fob beep or buzz when it gets used, along with a panic button that the user could hit on the fob to force the car off and set off the alarm. To defeat against the attacker cuts off the amplifier just after getting the car started, have the car shut off if it loses contact with the key fob within the first 15 seconds.
Edit: just thought of another possibility -- use spread spectrum. An amplifier would have to be tuned to a specific frequency. With spread spectrum, the car and key fob switches frequencies every second based on a cryptographic function, therefore defeating the amplifier.
- TheLoneWolfling 12y agoAn amplifier doesn't need to be tuned to a specific frequency. Look at SDRs. You can "tune" an SDR to tunnel an entire large chunk of spectrum.
- Syrup-tan 12y agoAdding on the idea of a specific frequency; what if the car also sends a few ``honeypot'' signals at different frequencies, near the real frequency. If the attack tries to amplify a given range, the honey pot signals will also be amplified, and the car can refuse to be opened.
- TheLoneWolfling 12y agoYou're assuming omnidirectional amplification. It's easy enough to amplify without leaking more signal back to the source than, say, a metal-faced wall would.
- raisedbyninjas 12y agoI think including a keyfob buzzer would be a hard sell. The whole purpose of these keyless entry systems is convenience and asking buyers to hover over their keyfob like a baby monitor is not convenient (nor cheap).