As far as I know no vehicles use this kind of rolling code algorithm for push button start, only key fob functions. Certainly not in Europe (due to immobilizer regulations) but I don’t believe anywhere else either.

Generally, long range key fob button functions and the short range start release functions are separated, both intentionally for security reasons and due to the different problem space occupied by each.

It’s also worth noting that European makes in general tend to have much better cryptographic key security. My understanding is that this is due to a combination of regulation, a relationship between insurance and automakers which requires some security standard, and a high rate of theft leading to an adversarial environment.

▲ majke 6 days ago | parent | next [-]

Can you expand on the “immobilizer regulations”? I wasn’t aware any of this was regulated in.

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bri3d 6 days ago | parent [-]

UN/ECE 116

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extraduder_ire 5 days ago | parent [-]

From a quick skim through the text, it seems to define what an immobiliser is, how it should work, and how it can be advertised on a car.

I don't see anything in there about them being mandatory across the EU. I know some member states passed laws mandating them before that document was published. Perhaps I got the wrong document.

	▲	bri3d 5 days ago \| parent [-]
		Also take a look at 74/61/EEC. Some form of “immobilizer” has been required in Europe since 1998, and between actual ECE/UN directives and insurance partnerships, the standard increases every few years.

▲ tekknik 5 days ago | parent | prev | next [-]

> Generally, long range key fob button functions and the short range start release functions are separated, both intentionally for security reasons and due to the different problem space occupied by each.

I don’t think this is true, for instance how does the key fob trigger a start sequence for vehicles equipped with remote start? They must be connected to the same CANBUS, so the key fob can interface with the start systems. This is also how a lot of vehicles are stollen, because of abuse/misuse of CANBUS (i.e. headlights being addressable in CANBUS)

	▲	bri3d 5 days ago \| parent [-]
		Yes, remote start breaks the model… which is why drive off release and remote start are separate systems. On modern European cars with automatic transmissions, the TCU will not release Park until the immobilizer (short range, challenge response) is released, and generally the ECU also limits torque request and vehicle speed. > This is also how a lot of vehicles are stollen, because of abuse/misuse of CANBUS On vehicles with poor cryptography architecture (Honda!), yes. On most other vehicles, no, because the immobilizer messages are cryptographically authenticated, usually by using an AES MAC where the key must encrypt random bytes transmitted by the immobilizer master using a shared AES key, and all participating immobilizer modules use a similar system to verify that every module shares the same secret material. Now of course if this secret material can be extracted the system breaks (see XHorse, Abrites, etc.) but this usually requires invasive and time consuming attacks far beyond the headlight thing (for example, removing and physically opening a control unit to use an exploit to dump its key material).

▲ inferiorhuman 6 days ago | parent | prev [-]

  It’s also worth noting that European makes in general tend to have much
  better cryptographic key security.

Counter point:

https://www.usenix.org/system/files/conference/usenixsecurit...

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bri3d 6 days ago | parent [-]

Hitag2, while broken, is worlds better than rolling code. All modern European cars that I’m aware of now use AES.

	▲	inferiorhuman 5 days ago \| parent [-]
		Right but the comparison was between Euro and American brands not between Hitag and rolling codes. In that regard the Euro brands are no better.