Firefox will probably survive if they bow and add WEI support.
I can’t imagine Google, Microsoft, and Apple opening themselves up to further monopolization scrutiny by trying to keep attestation restricted to their own browsers on their own operating systems.
Self-built or community forks are probably screwed, though.
And here’s a concern about the decentralized-but-still-centralized nature of attesters:
From my understanding, attesting is conceptually similar to how the SSL/TLS infrastructure currently works:
Each ultimately-trusted attester has their own key pair (e.g. root certificate) for signing.
Some non-profit group or corporation collects all the public keys of these attesters and bundles them together.
The requesting party (web browser for TLS, web server for WEI) checks the signature sent by the other party against public keys in the requesting party’s bundle. If it matches one of them, the other party is trusted. If it doesn’t, they are not not trusted.
This works for TLS because we have a ton of root certificates, intermediate certificates, and signing authorities. If CA Foo is prejudice against you or your domain name, you can always go to another of the hundreds of CAs.
For WEI, there isn’t such an infrastructure in place. It’s likely that we’ll have these attesters to start with:
But hey, maybe we’ll have some intermediate attesters as well:
Even with that list, though, it doesn’t bode well for FOSS software. Who’s going to attest to various browser forks, or for browsers running on different operating systems that aren’t backed by corporations?
Furthermore, if this is meant to verify the integrity of browser environments, what is that going to mean for devices that don’t support Secure Boot? Will they be considered unverified because the OS can’t ensure it wasn’t tampered with by the bootloader?
Adding another issue to the pile:
Even if it isn’t the intent of the spec, it’s dangerous to allow for websites to differentiate between unverified browsers, browsers attested to by party A, and browser attested to by party B. Providing a mechanism for cryptographic verification opens the door for specific browsers to be enforced for websites.
For a corporate example:
Suppose we have ExampleTechFirm, a huge investor in a private AI company, ShutAI. ExampleTechFirm happens to also make a web browser, Sledge. ExampleTechFirm could exert influence on ShutAI so that ShutAI adds rate limiting to all browsers that aren’t verified with ShutAI as the attester. Now, anyone who isn’t using Sledge is being given a degraded experience. Because attesting uses cryptographic signatures, you can’t bypass this user-hostile quality of service mechanism; you have to install Sledge.
For a political example:
Consider that I’m General Aladeen, the leader of the country Wadiya. I want to spy on my citizens and know what all of them are doing on their computers. I don’t want to start a revolt by making it illegal to own a computer without my spyware EyeOfAladeen, nor do I have the resources to do that.
Instead, I enact a law that makes it illegal for companies to operate in Wadiya unless their web services refuse access to Wadiyan citizens that aren’t using a browser attested to by the “free, non-profit” Wadiyan Web Agency. Next, I have my scientists create and release a renamed versions of Chromium and Firefox with EyeOfAladeen bundled in them. Those are the only two browsers that are attested by the Wadiyan Web Agency.
Now, all my citizens are being encouraged to unknowingly install spyware. Goal achieved!
With regard to my examples, WEI provides full confidence and stability in identifying the browser.
Relying on detecting browsers by differentiating between their features and quirks involves on having a large suite of checks to run, some of which might become incorrect as browsers change over time. It’s a maintenance burden, to say the least.