This isn't true, and I have the patent(s) to show it.
I developed (along with some truly talented security professionals and cryptographers) the active RFID security system for KIWI, a residential access control system here in Germany. One of the requirements, aside from not keeping a central log of access, was that the system should not work if you were further than 10 meters from the door you were trying to open. Things like measuring signal strength, etc. were not an option, as you might imagine repeaters render that moot.
Ultimately, it comes down to fairly tight timings, the speed of light and the rules of physics, but we could restrict things such that the cryptographic handshake would fail if you were more than about 30 meters away, corresponding to a timing window of about 0.0000001 seconds.
We offered to license the technology to car companies, but they weren't interested.
> I developed
> Ultimately, it comes down to fairly tight timings, the speed of light and the rules of physics, but we could restrict things such that the cryptographic handshake would fail if you were more than about 30 meters away, corresponding to a timing window of about 0.0000001 seconds.
Prior art! ;)
There are actually a lot of patented ways to prevent relay attacks, mine is only one of them. And most of them are patented by NXP :)
Ultimately, this is a failure of prioritization on behalf of the car companies, or a sacrifice of security for usability, or both.
I don't have any links and found only [1] this one quickly.
[1] https://teamtalk.jaguarlandrover.com/news/jaguar-land-rover-...
Well, I'm sorry for your tech, but you're kind of making OP's point:
> Yes, 99.9% of consumers really like keyless entry and don't care too much about the potential of theft. For most, that is what insurance is for.
https://www.righto.com/2022/04/the-digital-ranging-system-th...
https://networkingnerd.net/2016/09/21/apple-watch-unlock-802...
In an open plan office it works around 2 meters away at maximum.
There seems to be some kind of heuristic when it allows it too, the first login for the day requires a password or TouchID to be used, but the ones after that work via the Watch.
Identity verification and public/private keys are a solved problem, how is it at all impossible to prevent relay attacks?
Key: I want to unlock the door.
Car: Here's a random number encrypted with my key, which only the real fob should have the pair key to.
Fob: Here's the number encrypted with another key, which only the car should have the pair key for.
Car: This matches, opening the door.
Blindly repeating these bits won't work and it should be impossible to eavesdrop without an NSA cluster of supercomputers. What am I missing?
Every keyless/wireless car key already uses a challenge-response scheme, just like you described, to prevent replay attacks. However, that will not work against relay attacks. Cryptography does not prevent relaying.
Fun fact: Even most physical car keys produced >1990 have a small RFID based transponder in the key head (the plastic part that you hold). This transponder responds to a challenge transmitted by the ignition barrel. Without a correct response, the ECU will refuse to start the engine. This is mainly done to prevent 'Hollywood' style theft where you connect 2 wires from the ignition barrel together to start a car.
They used a relay attack which means that they tunneled the actual keyfob signal over the internet (or a direct connection).
Tesla and others try to mitigate that by making sure that the latency of the signal is not too high.
<Everything you described> Car: your encrypted authentication looks right but you took 200ms to send it. You are probably not within BLE range.
The researchers contribution was to show that despite that a relay attack is still possible.
I believe they have an option where you need a pin to start the engine at least however I'm not an owner
What a world!
The attack is defeated by keeping your fob in something that blocks radio frequencies I guess. Same idea as those metal wallets but this time for an actual threat.
Using latency seems intrinsically expensive because there's no lower limit to how fast a network switch or relay can operate, meaning speed of light is the only real limit. And then the latency bounds get extremely tight, which probably means expensive components. Probably too expensive for a dedicated key fob, but maybe possible with a phone.
But position is actually the thing we care about. If the key knows its position, say with GPS, then we could do it. The key could securely sign its location (plus timestamp or nonce to avoid replay attacks) and then the car could explicitly verify the signature and that the key is within range. AFAICT this is totally secure and reasonable, if a bit expensive, to implement. In fact it seems like it would almost just work today for phone-based keys.
Putting GPS into a dedicated key fob is probably not even too expensive - car key fobs regularly cost hundreds of dollars to replace, even if their BOM is trivial, and a cheap GPS watch is approaching $100. The biggest barrier I see here is battery life on the key - neither phones nor watches like to be constantly tracking GPS because of the power draw.
I wonder what else could work. Quantum communication protocols can detect or resist relays. These are WAAY out of reach though - mostly theoretical, but IIRC the Chinese actually built a satellite to do relay-resistant quantum key distribution.
I'm not arguing that these options are things car companies are going to do any time soon. But it's fun to think about. And I don't think it's impossibly far off.
stealing internet connected smart car is incredibly dumb
Encryption + timestamp + message that expires after MAX_DISTANCE/c seems like it would be pretty foolproof. There are of course some challenges in having enough precision in the clocks, though.
- Relay attacks can theoretically be solved with high precision clocks, but will affect price and reliability in a negative way
This obviously depends a bit on the situation, but most relay attacks happen within reasonable proximity. Most attacks happen to a car parked in front of a house, since the attacker knows that the keyfob is likely to be within the house. The distance here is often less than 20m. To get reasonably reliable relay detection on these kinds of distances, you'll need very precise clocks, which will make the keyfobs expensive and still increases the risk of false positives on relay detection.
What's the point (to the customer) if the expensive ULTRA SECURE (tm) keyless entry system is 10x the price, and still less reliable than the keyless entry system om their 20 year old Toyota?
Imagine your engine shutting off on the highway, and your steering wheel locks, just because the car briefly looses response from the keyfob...
Also, just about every keyless entry systems have a physical backup key, to start and drive the car in case the battery in the keyfob is empty. A periodical re-authentication would make this impossible.
Stuck in the middle of the desert with a perfectly good car, but an empty keyfob battery? Well, sucks to be you, you'll likely die, but at least your car won't be vulnerable to relay attacks!
Additionally, the highway scenario could also be mitigated with a warning and a grace period. The desert scenario can be mitigated with having a fallback such as having the contactless system double as a smartcard you can put into a reader or by wireless power transfer. Plus, if your contactless system fails in the desert you're screwed anyway as soon as you turn off the engine once.
Right, stop once for a traffic jam, car loses sync with keyfob, and you'll become a stationary target on a highway.
Better swap out those batteries in your keyfob real quick before that 18-wheeler smashes into your car with kids in the backseat!
But hey, at least your car won't be stolen!
> Problem solved.
I guess this proves my point I was trying to make in my original post. Every xx months a sensation article like this comes out, and suddenly everyone, even on HN, becomes an expert that will 'just' solve the issue with a naive solution.
Car manufacturers, hire smart engineers. If the solution was simple, they would have fixed it already. Cars are always a trade-off between safety, security, reliability, affordability and practicality.
Great that your solution makes car theft resistant, but if also kills people, it's not such a great sell...
I doubt Tesla would want to include a motion sensor on the dumb card that fits in a wallet.
Its not like a normal IT security problem where attackers can be anywhere on earth.
I dont know the numbers for the US, but in my country it seems 0,9% of cars gets reported stolen a year, which includes stupid stuff like leaving the car idling outside your view. Thats a risk I can live with and don't want to have bothersome security to avoid.
- Relay attacks are nothing new, and not unique to Tesla.
- Every contactless unlock technique is vulnerable to relay attacks.
- No amount of encryption prevents relay attacks.
- Short range/near field wireless standards (such as NFC) are also vulnerable, though requires close proximity of the attacker to the NFC token (phone/card/keyfob).
Even HN often falls victim to these kind of sensational headlines. No, we can't solve this. No, car manufacturers won't go back to physical keys. Yes, 99.9% of consumers really like keyless entry and don't care too much about the potential of theft. For most, that is what insurance is for.