EXIF data is stripped for a good reason - because it can be a privacy hazard. Suddenly this plays no role anymore?

Signing the raw image data wouldn't require also signing the EXIF metadata. For privacy, you could later strip out everything except the raw image and the camera's signature and still prove that the image is unaltered.

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cortesoft 4 hours ago | parent | next [-]

What are you signing it with, though? A unique key that only exists on your device... so it will perfectly tie a photo to a specific camera.

Even if you didn't know who owned the camera, you could identify other pictures taken by that same camera, and information in those photos might let you figure out who owns the camera.

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smalltorch 5 hours ago | parent | prev [-]

I think he's saying the existence of a camera signature is the privacy issue maybe.

	▲	lokar 5 hours ago \| parent [-]
		You can remove it all. If authenticity later becomes an issue you can produce the original.

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doc_ick 5 hours ago | parent | prev | next [-]

Ontop of this, including a photo edit history in a photo including the original photo would increase the size of a photo to be completely unusable or unshareable.

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xg15 5 hours ago | parent [-]

I understood the GP so that only some unique ID or hash of the original image would be included, not the image itself. Basically like the commit chain of Git but without the actual content blobs.

You could use this data to prove that image B is an edit of image A if you already have both A and B.

I still think this is a bad idea, because this all requires the images to have some sort of ID - and that seems like a prime target for tracking.

	▲	lokar 4 hours ago \| parent [-]
		You can publish a fully stripped image (as people do now for exif), and retain the original

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hamdingers 5 hours ago | parent | prev | next [-]

In the contexts where you need to prove an image is a real unaltered photograph (court cases, news media, science, etc) privacy is usually not a concern.

Nobody cares if your social media photos are edited, they probably are, it's fine.

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xg15 2 hours ago | parent [-]

I'm pretty sure if signing images becomes the norm, because cameras will do it automatically then social media sites etc will start to care - or at least be thankful for the additional metadata.

	▲	theamk an hour ago \| parent [-]
		EXIF already includes extensive metadata, including phone model and GPS location. For professional cameras, there is often camera and lens serial numbers too. This has been the case for many years, and so far social media sites never care - they strip that info instead. Why would this change with one more extra piece of metadata?

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xoa 3 hours ago | parent | prev [-]

>EXIF data is stripped for a good reason - because it can be a privacy hazard. Suddenly this plays no role anymore?

Can you clarify what your actual complaint is here? Putting aside for a second obvious implementation options, it's pretty standard that there can be a tradeoff between privacy and trust. Any of us are still perfectly free to upload images for fun to forums or social media or whatever that are private, or edited or whatever we like. But if there's something we [i]want[/i] to prove, this gives an extra option to do so. And in particular the set of cases where one cares the most about enhancing authenticity appears at first thought to be pretty much a union set with the cases where one will put their name (or at least the location and time of the picture in question) behind the image? Like, can you give examples of specific cases you are imagining where simultaneously the photo itself reveals no information about time and location [i]and[/i] it's something local/national/international-newsworthy where people would fear AI-alteration? Like, say you're photographing at a protest to document it including any violations of law. By definition, the images you take reveal the location and the time. That's the whole point of them. Having the location and timestamp signed wouldn't reveal anything extra as long as the photo was unaltered.

And actual legit journalism always has name(s) standing behind the reporting. Or for that matter, even if we're merely talking something like a review of a product, is it actually wrong to put a name or pseudonym behind that review if you expect readers to give you much credence? I mean, you'd be free in terms of law and tech to not bother. But even long before the current growing AI-slop age a lot of us have been starting to treat anonymous reviews with a lot of skepticism, or discounting them entirely for some product classes, for good reason.

Even in terms of maintaining privacy, remember we already have "tools" for that which this in turn could further help. You could privately report a tip to a reporter at a media organization, and then they could report on that without revealing you but be able to say "we verified the signature of the raw image and sensor data" alongside normal follow up. Then it's their name, but having a stronger chain behind it could still be helpful in places.

Finally getting back to "implementation options", there's no technical reason the image and multiple sets of metadata can't all be signed separately by the sensor stack such that you can pick & choose what to include and still have it all be signed, with readers giving greater or lesser weight to the trust based on your choices.

	▲	xg15 2 hours ago \| parent [-]
		I think what got me worried is the GPs take that "I expect in the near future all digital cameras to digitally sign the images they take". Sure, if you have your special, verification-enhanced camera, go for it. But if this goes like with smartphones and we have all cameras embedding such a signature - and therefore all cameras are made locked-down and tamper-resistent - then we have another category of devices removed from control of their users. > Any of us are still perfectly free to upload images for fun to forums or social media or whatever that are private, or edited or whatever we like. First, the paper proposed a method of embedding the metadata inside the actual image pixels in a way that makes it difficult to remove. I think it's still possible, but you're will need a specialized tool to do so and it will alter the image. Second, that's assuming forums or social media would still be allowing uploading unsigned images. If AI images really become as much of a problem as anticipated here, then sites might decide to block any image they can't verify completely. > Like, can you give examples of specific cases you are imagining where simultaneously the photo itself reveals no information about time and location [i]and[/i] it's something local/national/international-newsworthy where people would fear AI-alteration? All kinds of photos from warzones have this property. We wouldn't have an entire science of geolocating photos from landmarks that were accidentally captured if everyone was so easy with putting their GPS coordinates in the file.