Aside from the fact that this was obviously never viable and the entire problem is clearly unsolvable if you sit down and really probe it for fifteen minutes, what I find most frustrating about this is that the false promise of preserving photos as reliable evidence is actively harmful.

You will not build a perfect system, or even something near perfect. The best you're going to do is make it so that it's hard to casually present AI photos as real, leaving only the cases where it really matters. In the "best" case, you've just made the public more trusting of photos in general, so that when there's actual money or power on the line that makes jumping through the hoops to fake authenticity worth it, the public is more susceptible.

The best outcome at this point is for everyone to get on the same page that photos have roughly the same probative value now as drawings. Poorly thought out snake oil efforts to prove authenticity are only going to delay that.

I always got the impression that C2PA is a way to say "this photo came from the BBC (for example) and they've only signed it because they've verified the supplied edit chain". It's always been obvious that one could point a camera at a screen, I don't think anyone involved with C2PA has claimed otherwise.

It seems like there's a big disconnect between what C2PA says it's for and what certain journalists think it's for.

It's compliance for advertising. Your client doesn't want AI in their project you show them the audit trail and if it turns out to be faked you point to the supplier who faked it. Our agency signed a insurance not only because of clients who don't want to use AI in their artwork but also because of the EU AI act. They c2pa to get their money back from a cheating supplier if they are not compliant with the AI act.

I'm very surprised Google put in so much effort to implement an approach that is basically the equivalent of client-side verification of passwords. Did no one designing it mention that it could be defeated by any rooted device?

Even at the hardware level, if it was a separate chip that the camera data passed through or something, that's not really good enough either, people have broken TPMs before. It'd have to be baked into the camera sensor. Even then, you could attack it from the next level up, with some fancy optics and a display, or something like that.

I don't think completely solving this sort of problem is even possible.

I can break it with zero skills. Tripod, camera, clear monitor in a dark room ... just take a real photo of a fake photo.

I got a good laugh out of the "unblur to verify" first image. I dont know what I was expecting to see.

I would be interested in a note on whether Sony / Leica / Olympus “content credentials” do any better with their hardware to ensure a signature is assigned to data straight off the sensor.

Surely the easiest thing to target is photos taken by journalists and modifications, down sampling etc when shared to twitter?

I expect the only plausible chance (and it is a stretch) will be at-the-censor marking. Quantum bla bla magic pixie dust or unicorn farts something. The chance of a trustworthy (including from nation-state tampering a la Stalin et al) means of verification of digital anything is as good as dead imho.

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I have a feeling Apple is going to knock it out of the park on this when they get around to it. They have a great foundation for doing image provenance well. The device attestation workflows are already there. And the same attacks that work against Android won't be as easy or effective because of Secure Enclave. Apple could run the whole signing process inside SEP.

And, Apple could choose to integrate a LiDAR depth map into the signed photo as a mitigation against the analog attacks (eg. pictures of screens).