4 ms·

Not to operate (I'd never purpose such a travesty) but it could work sort of like carfax. Go to buy a used car, Oh it's never been synced with the cloud in its

Not to operate (I'd never purpose such a travesty) but it could work sort of like carfax. Go to buy a used car, Oh it's never been synced with the cloud in its 3 years of existence? I find that rather suspect. Knock off a couple grand.

joezydeco 12y ago
If you pay me $50/year I'll have my server spoof the packet report from your car to the manufacturer's server. It will transmit twice a day at 8:45am and 5:15pm to show the car being driven 5 miles to work and back. Hell, I'll even throw in a lunch outside the office once in a while. Your turn.
- toomuchtodo 12y ago
  Looking forward to your attempt to sidestep crypto. I'll wait while we exhaust the entropy of the universe in a futile attempt to "spoof" a vehicle checking in.
  - joezydeco 12y ago
    If I have the car in my driveway, I don't see it being a universe-ending project. We've extracted keys out of way smaller devices.
    - poizan42 12y ago
      There's a point here though. Someone somewhere can extract the key out of a single car, but if you have a per-car key and you need to decap a chip and put it under an electron microscope to get the key then it quickly becomes infeasible.
- cmdrfred 12y ago
  There is no perfect system for anything but you can probably take it to the point where an attacker won't profit from his efforts, and I see that as a reasonable goal post for a threat model here. I implement a RSA key for each car, signed before it leaves the factory. Each key is housed in memory that is heavily epoxied and very difficult to remove (in a place that you would have to remove the majority of the engine to reach). The cars ignition system requests validation from the on board key on every start (in fact it gets the actual <start car> command from the chip itself). If the key is not present, the car does not start and instead tells you to return it to the dealership. Now you say, I can remove the key and then reverse engineer it. What if I put n keys? How many do I realistically have to add to make it so time and labor intensive for you to remove my little inexpensive keys that you just give up? Probably not that many. Oh and did I mention that all of them are in an array? Better be sure you didn't miss one or it will zero itself out giving you no hope of recovery. (The warranty specifically mentions this as something that will void it) After all that, if you still want to attempt to modify it. Fine. I'll add 1% to the purchase price of the car and reimburse anyone who bought lemons from your little (illegal) scheme.

joezydeco 12y ago

If you pay me $50/year I'll have my server spoof the packet report from your car to the manufacturer's server. It will transmit twice a day at 8:45am and 5:15pm to show the car being driven 5 miles to work and back. Hell, I'll even throw in a lunch outside the office once in a while. Your turn.

toomuchtodo 12y ago
Looking forward to your attempt to sidestep crypto. I'll wait while we exhaust the entropy of the universe in a futile attempt to "spoof" a vehicle checking in.
- joezydeco 12y ago
  If I have the car in my driveway, I don't see it being a universe-ending project. We've extracted keys out of way smaller devices.
  - poizan42 12y ago
    There's a point here though. Someone somewhere can extract the key out of a single car, but if you have a per-car key and you need to decap a chip and put it under an electron microscope to get the key then it quickly becomes infeasible.
cmdrfred 12y ago
There is no perfect system for anything but you can probably take it to the point where an attacker won't profit from his efforts, and I see that as a reasonable goal post for a threat model here. I implement a RSA key for each car, signed before it leaves the factory. Each key is housed in memory that is heavily epoxied and very difficult to remove (in a place that you would have to remove the majority of the engine to reach). The cars ignition system requests validation from the on board key on every start (in fact it gets the actual <start car> command from the chip itself). If the key is not present, the car does not start and instead tells you to return it to the dealership. Now you say, I can remove the key and then reverse engineer it. What if I put n keys? How many do I realistically have to add to make it so time and labor intensive for you to remove my little inexpensive keys that you just give up? Probably not that many. Oh and did I mention that all of them are in an array? Better be sure you didn't miss one or it will zero itself out giving you no hope of recovery. (The warranty specifically mentions this as something that will void it) After all that, if you still want to attempt to modify it. Fine. I'll add 1% to the purchase price of the car and reimburse anyone who bought lemons from your little (illegal) scheme.