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Comment by PretzelPirate | Hacker News Reader

Why can’t I just use a message signed with my existing private key to access my car? Why does Tesla need to have servers in the middle?

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Tesla cars support:

* Unlock by NFC keycard * Unlock by bluetooth using the app * Remote start by app (over the cell network)

AIUI the latter was down. I don't think the bluetooth would be down - that one works even without cell service - but I didn't try it during the time of the outage. Regardless, you really should carry the keycard around just in case your cellphone runs out of batteries or something.

Making access to a vehicle dependent on a cloud service also adds security vulnerabilities that didn't exist before to real world objects. Perhaps Tesla should partner with the MPAA to create a public service announcement about this. I can imagine:

"You wouldn't steal a web server..."

It’s not dependent. You have a physical keycard that lets you start and drive the car. The app also lets you start and drive the car with no internet over Bluetooth. The only thing not working here was the OTA remote administration of the car. The article is misleading.

You're right, I apologise. I (meant and) should have said something like "making the car's security dependent on", in the sense of a weakest link, or additional attack surface.

If the bluetooth works, I'm surprised the app wouldn't automatically switch to that when the RPC cloud call fails.

As far as I understand, the users could not open the app at all - because it could not connect to Teslas servers.

Interesting. Seems like that would be an everyday issue...plenty of dead spots in cell coverage, underground parking garages, etc. Or perhaps they check for "no network", but not "network is there, endpoint is borked".

The Bluetooth unlock worked fine during this outage. The only feature unavailable was “remote unlock/start” where the user is not within Bluetooth range of the car.

This is absolutely bonkers to me. Why does a car need electronics at all to open the door? Were they not bored enough in design?

My car has keyless fob-proximity entry and a key if the fob, or the car, runs out of battery power. Like a car does.

Why can’t you use a key to turn a lock?

It’s an electric car, it doesn’t seem unreasonable to have an electronic security system tied to locks, alarm and immobiliser. If there’s no power you’re not going anywhere anyway.

If there’s no power, you still need to be able to get in or out of the car. It doesn’t matter if the 12V or the HV electronics are failed: you cannot leave somebody with only breaking a window as the method of ingress or egress from a physically intact vehicle. It is genuinely mystifying.

There's a mechanical door handle on the interior.

If you run out of batteries completely and need to get in the procedure is:

1. Open a small panel on the front and apply 12V to the emergency cables to unlock the frunk (this only works if the car is powered off as I understand)

2. Jumpstart the car's low voltage battery, located under a panel under the frunk

3. Unlock and open the door normally

4. Attach an EVSE charger to get the HV back online as well

> There's a mechanical door handle on the interior.

Only the front doors in the Model Y[0] and Tesla warns using them "May cause damage to the window trim."

[0] https://i.redd.it/aicn8uafkto41.png

As a matter of practice, no one would carry a physical, metal key they use once a year. The key-card tackles this problem. It can be tucked away in a wallet.

I carry a physical, metal key for my car that I’ve used once in four years. It’s part of the key fob. It’s on my key ring. I carry a physical, metal key I’ve never used. It unlocks the back door of my house. I carry another physical, metal key I’ve never used too, now that I think about it: the one that unlocks the keypad front door if the battery dies.

Do you not have other keys? Or like, is it up to Amazon or whoever, along with battery electrochemistry, to let you into your house, too?

(“Physical, metal key”. That actually makes me incredulous, to be honest, as if carrying three grams is a burden. Are we just a parody of ourselves now?)

This is like carrying a thick wallet with every card you might ever need. It's logistically advantageous, but most of the time it just gives you back pain (thick wallets in back pockets mess up posture). You can do what works for you! But I like to stash fail-safe keys in strategic places, like a house key in the car, and a car key in the house.

By "physical, metal key" I'm just disambiguating between key fobs, key cards, phone-keys, and tumbler keys.

I only carry my phone and my wallet when I go out. If I’m driving I bring my car’s key fob, no attached keys. I get in through my garage. If the power is out for some reason, I can grab my spare key hidden on the property. Why would I want to bring a physical, metal key around with me? Is it the 1900s?

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