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by hunt 4064 days ago
Perhaps moving to a shorter distance transmission method would work. You could use NFC and then touch the fob against a portion of the door, placing the key in a cup holder (or something similar in the center console) with NFC support when you want to start the engine? It's not the exact same functionality, but is close.
4 comments
sp332 4064 days ago
Remember the adversary is boosting the signal, so their device doesn't have to be in a cupholder even if your key would.
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stonemetal 4064 days ago
But if we are going over a very short distance like NFC does then their amplifier is going to have to be close to the key. If my NFC key only works when it is within two inches of the door lock, your amplifier is going to have to be within two inches of my pocket to pickup the signal to amplify it.
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sp332 4064 days ago
Well... they might have a better antenna or just a bigger amplifier than your car does. And if they can just walk past you to unlock your car, that's still pretty unnerving.
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raisedbyninjas 4064 days ago
Creating a special hole to put the keyfob into sort of negates the already dubious benefit of these keyless entry systems.
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TheLoneWolfling 4064 days ago
That just means that the adversary needs to get the repeater closer to you. It mitigates it, but doesn't stop it.
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lsaferite 4064 days ago
Would triangulation of the signal not be effective?
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TheLoneWolfling 4064 days ago
Against this attack? Yes. Against a trivial modification of this attack? No.

(Trivial modification: you have two transceivers. Each transceiver encodes and encrypts everything in the frequency range, and sends it to the other one, which decrypts it and rebroadcasts it.)

Think of the original attack as being the equivalent of placing a megaphone up against the guy whispering, and this attack as being the equivalent of placing a cell phone up against the guy whispering and another cell phone that's connected to the first one up against the guy waiting to hear something.

Not to mention that triangulation has... problems. You really don't want your car to not open because there was a stray reflection off of something nearby.

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