GM 5 byte seed/key tool

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kur4o
Posts: 948
Joined: Sun Apr 10, 2016 9:20 pm

GM 5 byte seed/key tool

Post by kur4o »

Found a link with 5 byte seed/key generator. Seed needs to be valid and conforms to some unknown special rules, so you can`t just use random seed for testing.

https://universalpatcher.net/gm-5-byte-keys/
ironduke
Posts: 579
Joined: Thu Feb 13, 2020 11:32 pm
cars: Mainly GM trucks, a Cruze and an Equinox for dailys..

Re: GM 5 byte seed/key tool

Post by ironduke »

Just a quick review for anyone wondering, it works quite well for E92,E82,E78 and E39a...
In-Tech
Posts: 778
Joined: Mon Mar 09, 2020 4:35 pm
Location: California

Re: GM 5 byte seed/key tool

Post by In-Tech »

Wow, I missed this somehow. I will try it out. Thanks kur4o and ironduke :)
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Gatecrasher
Posts: 272
Joined: Sat Apr 25, 2020 6:09 am

Re: GM 5 byte seed/key tool

Post by Gatecrasher »

The only rule I've been able to guess at so far is that SPS seeds need to end with either 01 or 06, and DVT seeds need to end with 0C.

I think I also read that if you feed it a seed of 11 11 11 11 11, you should get 55 55 55 55 55 for the key. Or maybe I've got that reverse. But it's supposed to be used for testing your code implementation.
gmtech825
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Joined: Fri Feb 24, 2017 11:27 am

Re: GM 5 byte seed/key tool

Post by gmtech825 »

has anyone figured out the DVT algo?
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Gatecrasher
Posts: 272
Joined: Sat Apr 25, 2020 6:09 am

Re: GM 5 byte seed/key tool

Post by Gatecrasher »

I suspect it's the same theory, but a different set of crypto values. This is a half wild guess, but I think the constant references to SA015BCR are "Security Access 01 5 Byte calc (crypto?) routine".

So there's probably a similar SA035BCR within GM for DVT functions.
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