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C2PA Cameras Do Not Survive Contact with Reality

da.vidbuchanan.co.uk

51–60 of 153 posts

Re: C2PA Cameras Do Not Survive Contact with Reality

#51

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.

Why would someone paying for an expensive camera to damage the pixels of their images with "invisible" watermarks?

The signature doesn't touch the image data in any way. It's just a piece of metadata attached to the image, like any other metadata tag.

Re: C2PA Cameras Do Not Survive Contact with Reality

#52
post #50

Isn't film photography verifiable with a physical negative? i.e. you could verify a digital reproduction of the analog photo by comparing the digital image with the negative. Tedious, but sound?

You can expose a negative with whatever the fuck you want. It doesn't have to be a real scene.

[deleted]

Re: C2PA Cameras Do Not Survive Contact with Reality

#53

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 fo…

Why not just have BBC sign stuff with their own creds then? You can originate the chain of custody anywhere and relying on the camera is kind of silly when the reputation of the original publisher in a more meaningful backstop.

Re: C2PA Cameras Do Not Survive Contact with Reality

#54
post #41

Earlier quoted context omitted.

Are we entering a world where if I took a picture with a film camera and scanned it, it would be rejected as not real? This is ridiculous.

The defendant submitted a remarkably high quality video of you saying you generated it with Nano Banana.

And their video was C2PA signed.

Re: C2PA Cameras Do Not Survive Contact with Reality

#55

Isn't film photography verifiable with a physical negative? i.e. you could verify a digital reproduction of the analog photo by comparing the digital image with the negative. Tedious, but sound?

Does that prove you didn't photograph a display showing the digital image?

Re: C2PA Cameras Do Not Survive Contact with Reality

#57

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 cas…

I think it's useful even if it can be spoofed. Many people don't even bother to edit visible watermarks out of AI photos/videos. I'm fairly certain this will defeat 99.9% of malicious users, many of whom won't even know it exists until someone points out it's missing.

People are concerned that the technology will lend additional credence to the last 0.1%. But anyone who thinks about the technology for 2 minutes will see you can just point the camera at the screen. In cases where it really matters (a court of law, internet arguments between nerds) people will know it's not 100% reliable. Locks can be picked, and signatures can be forged, but that doesn't make them useless.

"C2PA Cameras Do Not Survive Contact With Reality" does not survive contact with reality where very, very few users would even think of rooting their phone so they can create signed fake images.

Re: C2PA Cameras Do Not Survive Contact with Reality

#58
For the time being, I wish more workflows revolved around RAWs. You can pretty much prove the origins of an image sans cryptography by just possessing the image sensor data that you used to produce the final. It's not foolproof but AI image models can't really generate a convincing bayer raw and it's not something anyone is going to spend significant time training.

Re: C2PA Cameras Do Not Survive Contact with Reality

#59

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 cas…

I don’t think there is a technical solution to this problem but I think there is a legal one.

Make it a legal requirement to mark AI generated photos and enforce penalties for posting unmarked AI generations. Social media should also mark the country of origin for each post, with the knowledge that posts from your own country are covered by these laws.

Re: C2PA Cameras Do Not Survive Contact with Reality

#60

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 fo…

C2PA is a bit nebulous as a concept, which is part of the problem. It is both of these things. The BBC type use case where a publisher signs their own content with their own keys seems reasonable to me, or at least, not obviously broken.

However I question the value-add when e.g. the BBC website is already authenticated by nature of being served over HTTPS, and anyone who redistributes BBC content can and should link back to the source.

> 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.

They haven't claimed otherwise exactly, but some have implied it's a solvable problem. Here's where the "learn more" link goes, for when Youtube annotates a video as having C2PA metadata: https://support.google.com/youtube/answer/15446725 (Google is a C2PA Steering Committee member)

> The metadata that leads to a 'Captured with a camera' disclosure is made by a third party (for example, a camera manufacturer). This means that there is some risk that someone could take a photo of another screen showing synthetic content. Because the other screen shows an image that has been modified, it wouldn't be eligible for the 'Captured with a camera' disclosure. This issue is called 'air-gapping'. Camera manufacturers will continue to develop detection measures to prevent 'air-gapping', but the sophistication of those detection measures may vary in the near term.

Interestingly they do not mention any of the other known limitations. Their phrasing is highly weasel-wordy, but the implication is clearly that they imagine picture-of-screen detection to become robust (somehow) in the medium-to-long term.

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