The whole point of the majority of PKI (including secureboot) is that some third party agrees that the signature is valid; without that even though its “technically signed” it may as well not be.
The first party must be able to entirely decide that "some third party" for it to be anything more than an obfuscation of digital serfdom.
But in reality this trustworthiness check is handed over by the manufacturer to an infrastructure made up of these trusted parties in the owner’s name, and there’s nothing the owner can do about it. The owner may be able to validate software is signed with the expected key but still not be able to use it because the device wants PKI validation, not owner validation.
I’ve been self-signing stuff in my home and homelab for decades. Everything works just the same technically but step outside and my trustworthiness is 0 for everyone else who relies on PKI.
My definition of PKI is the one we’re using for TLS, some random array of “trusted” third parties can issue keys that are then validated against.
If you’re not in that list then signing can be valuable for other reasons, but PKI is not among them any longer as theres no distinction between self-signed and a semi-trusted entity: things will break.
If you expect your website to work with keys issued from your internal company CA; you would be surprised to find that random browsers distributed on the internet wouldn't trust it.
Wow, shocker.
Maybe read the actual definition before assuming you're so much smarter than "HN". One doesn't need third parties to have pki, it's a concept, you can roll out your own
I’ve been discussing the practical implementation of PKI as it exists in the real world, specifically in the context of bootloader verification and TLS certificate validation. You know, the actual systems people use every day.
But please, do enlighten me with whatever Wikipedia definition you’ve just skimmed that you think contradicts anything I’ve said. Because here’s the thing: whether you want to pedantically define PKI as “any infrastructure involving public keys” or specifically as “a hierarchical trust model with certificate authorities,” my point stands completely unchanged.
In the context that spawned this entire thread, LineageOS and bootloader signature verification, there is a chain of trust, there are designated trusted authorities, and signatures outside that chain are rejected. That’s PKI. That’s how it works. That’s what I described.
If your objection is that I should have been more precise about distinguishing between “Web PKI” and “PKI generally,” then congratulations on missing the forest for the trees whilst simultaneously contributing absolutely nothing of substance to the discussion.
But sure, I’m the one who needs to read definitions. Perhaps you’d care to actually articulate which part of my explanation was functionally incorrect for the use case being discussed, rather than posting a single snarky sentence that says precisely nothing?
EDIT: your edit is much more nuanced but still misses the point; https://imgur.com/a/n2VwltC
Besides the "what does pki mean" discussion, as for who "misses the point" here, consider that both sides in a discussion have a chance at having missed the original point of a reply (it's not always only about how the world is / what the signing keys are, but how the world should be / whose keys should control a device). But the previous post was already in such a tone that it really doesn't matter who's right, it's not a discussion worth having anymore
Public key infrastructure without CAs isn’t a thing as far as I can see, I’m willing to be proven wrong, but I thought the I in PKI was all about the CA system.
We have PGP, but that's not PKI, thats peer-based public key cryptography.
Unless there's legislation to force them to allow enrolling new keys or otherwise disabling secure boot, the abuse will continue.