[Ovmsdev] BCM seed key algorithm Maxus Euniq6

[Collin Kidder]

Well, it's tough to give definite suggestions without the sample list of
seed-key pairs. But, checking simple xor, bitshift, known CRC algorithms,
and summing are the first steps. Generally, at least until very recently,
usually nobody bothered to put too much effort into the algorithms so they
tended to be fairly simple. One of the best things to do is to compare what
happens to the key when you change the seed. It's great if you can get
thousands of pairs and find some where the seed differs by only a single
bit. Sometimes that yields important clues.


On Tue, Oct 11, 2022 at 4:20 PM Jaime Middleton <jmiddleton at tucar.app>
wrote:

> Hi all,
> I am currently working on the implementation for the Maxus Euniq6. I have
> been able to decipher most of the metrics I wanted, but now I need to open
> and close doors.
> I was able to get access to a scanner for the car and sniff the can while
> the scanner opened and closed the doors.
> I mostly deciphered the interaction between the car and the scanner but
> there seems to be a seed-key algorithm in order to authenticate the scanner
> with the car. (I have ruled out a simple xor of bitshift).
> Any ideas on how to decipher this?
> I have a list of seed-keys and the chatter before in case someone wants to
> take a look.
> Any help is greatly appreciated.
>
> Thanks,
>
> Jaime Middleton
>
> Software Engineer
>
> Tucar Spa
> ------------------------------
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