The Use by Other EVs of Tesla Supercharges?

[deonb]

Sorry, but what century do you think you are living in?

But really, there are about 100,000 authorized VINs at 4 bytes per, so 1/2 a meg... Let me know when we get up to the smallest SD card you can buy.

Sure, and we know they have connectivity since Tesla use this for capacity monitoring purposes, and to send letters to locals who charge.

So Tesla can certainly send a list of authorized VINs to the Superchargers. However, it is a simpler implementation to just upload the set of Supercharger permissions to each car and sign it.

Either mechanism would work though. I guess depends on the Engineer who implemented it. If they are from an ex-desktop world they would have probably used a list of allowed vehicles. If they're from an ex-web world they would have used signatures.

Thank you kindly.

That's a pretty condescending way to try and get your point-of-view across...

 

[electracity]

"Thank you kindly" is his preset signature. A bit wierd, but not directed at you.

Remember that the supercharger can kill if erroneously/maliciously activated. It has been secure since day one.

 

[Topher]

That's a pretty condescending way to try and get your point-of-view across.

That voice you hear in your head that sounds condescending is yours, not mine. I like to thank people who engage in our mutual conversation. Go read one of my posts that you agree with, and see if that sign off sounds better. I mean it that way every time.

I do find it amazing that on the internet where ALL CAPS, massive profanity, and every other sort of anti-social behavior is de riguer, my simple politeness is taken badly.

You do have my apologies if my humor seemed at your expense. I just found the idea that there is some place on the world where one can't communicate (to say nothing of one with lots of electricity) hilarious.

Thank you kindly.

 

[deonb]

Remember that the supercharger can kill if erroneously/maliciously activated. It has been secure since day one.

Signatures are secure. Virtually every financial transaction you do on the modern web that have multiple stateless servers at the backend are protected this way.

It's different from an access list, but not less secure.

 

[stopcrazypp]

Here's wk057's comments on today's implementation, from another thread. While the car does send its VIN number to the supercharger station (so Tesla can do VIN based blocking if they wanted to in the future), the authorization currently is only done via a configuration variable in the car (which if Tesla wanted to disable authorization, they do so by connecting to the car via VPN):
Pack Swap on 70D to 90kWh HP?

Of course this does not preclude there being signed keys involved in between (such that other automaker's can't just replay a recorded charging session).

 

[SomeJoe7777]

Sorry, but what century do you think you are living in?

The one where we can put a man on the moon but can't avoid toll roads on our nav.

In all seriousness, yes I'm sure there can be communication to each supercharger and probably is. But it can't be relied upon 100% of the time, so you can't design the system so that the uplink is required to authorize a charging session. That's why I speculated earlier that you could periodically download VINs, keys, or whatever else to the supercharger on a daily basis, and then all authentication transactions are handled locally at the supercharger, whether it has the uplink or not.

 

[jgs]

Would love to see some of those logs. And true, they may not be encrypted, as that's not terribly necessary, but I would say there has to be some kind of authentication more than just the car's decision.

I don't know -- secure authentication isn't rocket science but doing it right isn't as easy as everyone thinks (that's why so many people do it wrong). And it's hard to see how the threat model justifies doing much more than the minimum necessary. So, they might be doing it (because it's not rocket science) but I don't see "has to be".

Edited to add: Consider that Tesla demonstrably considers Supercharger power quite literally too cheap to meter at present, and factor that into the question of how much they might want to invest in doing secure auth.

 

[SomeJoe7777]

I don't know -- secure authentication isn't rocket science but doing it right isn't as easy as everyone thinks (that's why so many people do it wrong). And it's hard to see how the threat model justifies doing much more than the minimum necessary. So, they might be doing it (because it's not rocket science) but I don't see "has to be".

Perhaps not now. Right now, Teslas are the only cars that can charge at a supercharger and their ability to supercharge can be fully controlled from the car's firmware. Thus, at the present time, the supercharger needs to do nothing.

But think about how that has to evolve if another manufacturer buys into the supercharger network. Tesla will not have control over their cars and their firmware, so the supercharger must now perform some type of authentication on the supercharger side. If not, Tesla can lose control of who can supercharge and who can't.

I firmly believe the capability for supercharger-side authentication must exist. Whether it's currently in use or not or how it works is debatable and speculative, but I can't imagine that the capability is not there.

 

[jgs]

That makes a lot of sense if you're thinking in terms of open protocols. But since it's a closed ecosystem, Tesla has the latitude to completely swap out the protocol at (relatively speaking) the drop of a hat. Future-proofing by firmware update (on the cars and the Superchargers both) instead of by thinking out the protocol in detail up front.

(I haven't reverse-engineered the protocol to know what it does, of course, nor do I see anyone else saying they have either.)

As you say, it has to change if another manufacturer buys in, but they have the freedom to deal with that as needed. Closed systems have their advantages.

Edited to add: Oh by the way, one thing that might necessitate strong authentication is if Model 3 does end up having a surcharge to enable Supercharging. At that point they will have hundreds of thousands of people on the road, all with some motivation to hack the protocol.

 

[deonb]

That voice you hear in your head that sounds condescending is yours, not mine. I like to thank people who engage in our mutual conversation. Go read one of my posts that you agree with, and see if that sign off sounds better. I mean it that way every time.

I do find it amazing that on the internet where ALL CAPS, massive profanity, and every other sort of anti-social behavior is de riguer, my simple politeness is taken badly.

Thank you kindly.

I'm all for using the same civility in an internet conversation as you would use in a face-to-face conversation, but saying thank you at the end of a disagreement is a sarcastic insult and an attempt to shut off further dialog.

E.g.
"I could care less what you think, thank you."
"I am buying this purse whether you approve or not, thank you very much."
"Would you die already? Thaaanks"
"I see you didn't put any time or effort into this. Thanks a lot.".

In each of those cases, the "thank you" serves to increase the negativity of the response, since it is pure sarcasm.

Especially since in context, your previous line in your reply " Let me know when we get up to the smallest SD card you can buy." was also sarcastic, it makes it doubly so.

If you only ever have positive responses then a blanket "Thank you" is fine. Insincere, but fine. But when you put it at the end of a negative response, then it's negative as well.

 

[deonb]

You do have my apologies if my humor seemed at your expense. I just found the idea that there is some place on the world where one can't communicate (to say nothing of one with lots of electricity) hilarious.

Since I had 4 days without access to Internet last week while I was travelling, I find it much less hilarious. There are tons of places in the center and western parts of the country where you can have good electrical service, but no Internet service - not even cellular. Keep in mind Tesla tend to put Superchargers in remote locations.

 

[jgs]

Since I had 4 days without access to Internet last week while I was travelling, I find it much less hilarious. There are tons of places in the center and western parts of the country where you can have good electrical service, but no Internet service - not even cellular. Keep in mind Tesla tend to put Superchargers in remote locations.

Yeah, I used to have T-Mobile too. :-(

 

[Adrien]

Just my added knowledge from reading around:

As posted previously the Wizkid wk057 has tinkered with how the traffic flows between supercharger and car. He found this:

"Here's how it works today: The car has a configuration variable ON THE CAR that enables or disables supercharging (all DC charging). When it is enabled on the CAR the car is able to connect to superchargers and the car does send its VIN to the supercharger. As of today, the supercharger doesn't care what the VIN is. I've sent it all 6's, all 0's, a Roadster VIN, a VIN from a 1983 Yugo... it doesn't care. If it's enabled on the CAR the superchargers will charge the car today.

So today, when Tesla blocks a car from supercharging they connect to the CAR via their VPN link, modify the CAR'S options configuration to remove the DC charging option, without the owner's permission (which I'm pretty sure is illegal, but who knows).

That's not say they wont change this eventually. But as of right now, that's how it works. Eventually the supercharger could reject based on VIN or something else, but today it doesn't care. That's how it SHOULD work, but it is not how it actually works.

For the record, I've turned supercharging back on (undoing Tesla's illegal configuration change) for a fully repaired salvage and it works fine. If they want to block it on the supercharger side, by all means."

Also judging by this youtube video, maybe they do have remote connections to the SCs. This could also be done by reporting through the car it's status, location, and if it's charging, but I don't think it could tell which stall it's in.....interesting stuff indeed.

Given that the patents are open for all now, I would think Tesla would be OK partnering with other automakers and start a fee structure for use. Maybe not though to avoid lines at the already busy SCs. All thoughts at this point, but I can see it happening.

 

[Topher]

Since I had 4 days without access to Internet last week while I was travelling, I find it much less hilarious. There are tons of places in the center and western parts of the country where you can have good electrical service, but no Internet service - not even cellular. Keep in mind Tesla tend to put Superchargers in remote locations.

No phone lines either? I know I am old, and remember 'modems', but still. No satellites? There is a big difference between what you can get with one cell phone, and what Tesla can arrange for their fixed location station.

Thank you kindly.

 

[Adrien]

I did a rough calculation of Tesla's electrical cost so far. You can see in the video the total kWh delivered is 119,350,808 kWh so multiply that by about 15 cents avg and you are at roughly $18M worth of electricity. Not bad considering how many are up around the world, and have been in use for four years. A fairly trivial amount, but as the network grows, I don't think it will be trivial to sustain....

 

[deonb]

No phone lines either? I know I am old, and remember 'modems', but still. No satellites? There is a big difference between what you can get with one cell phone, and what Tesla can arrange for their fixed location station.

No land lines. I carry both AT&T and Verizon phones, and neither of those worked. Sure Satellite would work, but Satellite data is insanely expensive. For Tesla to maintain even only 8 hours a day of connectivity would cost $12000 per month (Iridium) for a single Supercharger.

Either way - moot point now - wk057 already proved the car doesn't require the Supercharger to have connectivity.

 

[RiverBrick]

I did a rough calculation of Tesla's electrical cost so far. You can see in the video the total kWh delivered is 119,350,808 kWh so multiply that by about 15 cents avg and you are at roughly $18M worth of electricity....

You have to add the power on demand fees which can be quite high.

 

[TheBlackKnight]

There's virtually no chance Tesla is ever going to validate the SC connection with a VIN number - they aren't that stupid. The VIN number on a Tesla is nearly the least unique thing ever. Out of 17 digits there are what, like 5-6 unique digits at the end that are a manufacturing serial number that increments as they build cars? Yeah, super duper hard to guess that. Someone could just use the first 13 digits that are all the same for a given car type and then guess random 5 digit numbers for the end and constantly either stay ahead of a black list or find one on the white list.

No, VIN based validation is dumb. There are far more likely and secure methods out there.

 

[Topher]

The VIN number on a Tesla is nearly the least unique thing ever.

Umm, The VIN is by definition unique. And 'unique' doesn't take a 'least' modifier.

But it isn't secure, any more than Social Security number is secure, which is the important question if one is considering whether it can be spoofed.

Thank you kindly.

 

[Adrien]

Spoofing shouldn't be an issue. It's not simple to do so 99% of the population won't be doing this. In some cases misrepresenting a VIN is flat out illegal. Secure or not, in my mind, shouldn't be of concern. We aren't talking about updating firmware or drivetrain access, etc.