Question for the SHSH system

[sly nest]

I am trying to make sense out of the SHSH system so bear with me

Suppose an obscure scenario where the GID key for a set of devices was leaked and a way to extract the UID key from said devices was found. Would that make the entire system collapse for those devices?

[sly nest]

Bump
Geniuses enlight me with your knowledge

[plush vine]

no, GID keys are not related to the shsh system

those are used to decrypt firmware, not sign them

shsh blobs are captured responses using sha-1 (a9 and older) or sha-384 (a10 and newer)

https://gist.github.com/nikoyeah1/9fcf4b2f18494d3974777635f4fed60a

[sly nest]

This suggests that each device has a unique key which matches a private in apple's servers. So apple is holding all those keys at the same time?

Isn't that TOO many keys?

[plush vine]

each device series has a private key

iphone 11, 11 pro, 11 pro max, etc

[sly nest]

Ah alright

If that private key was to get leaked in some way, would that make the system collapse for a device series?

[plush vine]

yes

[sly nest]

Alright thanks

[tame rock]

Let us pray, that it will happen for all current device series. Then we can finally install Linux or Android on our iPads.

[sly nest]

It aint getting leaked. It just aint

[tame rock]

I know.🥲 But I wonder what the shsh System has to do with security. I mean it just prevents the user from installing a custom os or an old version of ios. An attacker couldn't make use of it if it was possible because one would need physical access and the data would probably get wiped and the owner would notice. On Android it is possible to modify the system if you unlock the bootloader but that would result in a warning message on every bootup so you will notice that someone modified your phone when you left it alone.

[plush vine]

if it happens nothing on your device can be considered secure

it would be fun for downgrading but you would not be able to store any sensitive data on your phone