If it an electrical contact in the door handle, it would be very difficult for anyone to monitor or inject other signals.
If the signals were audible sound, you'd know when someone was jamming it.
In practice, my number one use of a fob from a remote distance is locking, rather than unlocking, and those two operations don't have the equivalent security risk.
You could even take it a step further for extra safety: the door handle could have a slot that requires a specifically shaped piece of metal to be inserted. Only a piece of metal with the correct shape would allow the lock to be opened.
This has been attempted but unfortunately this algorithm is vulnerable to the #ScrewdriverHammer attack.
This would be very popular in East Asia. They love everything that beeps. Rice cookers play a melody, pedestrian crossings play a melody, garbage trucks play a melody. Japan is the country of beeps.
Yep, that's the simplest fix. Key is required in the door to open/unlock.
You'd think too that a firmware update to the car could enable that behavior. I mean most cars still have a physical lock on at least the driver's side door as a "back door" to getting into the car if the fob is non-operational.
This is exactly the benefit of the free software, and why having your own ability to fix, recompile and reinstall the software, is essential, even on things such as cars where you may think it's not needed or is too complex to handle.
Wouldn't the risk be the same if the same rolling code keys was used for both locking and unlocking?
I would be surprised if automotive manufacturers used separate rolling code keys for locking and unlocking.
Yes, what I meant is that such symmetry is not strictly required, and breaking the symmetry opens up ways to enhance security (of unlocking when you arrive) while keeping most of the convenience (of locking while leaving.)
For example, imagine "Lock" is a typical broadcast from anywhere within X meters, but "Unlock" requires touching the fob to an infrared port, and they use independent codes.