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Maybe cryptographers think this way, but I'm struggling to think of a case where a normal person had genuine photos leaked and then just baldly denied everythin

Maybe cryptographers think this way, but I'm struggling to think of a case where a normal person had genuine photos leaked and then just baldly denied everything. Deniability isn't an option most people use or want to use in practice. On the other hand, images faked by AI is a real problem.

smalltorch 5d ago
I don't think it's really the utility of deniability, rather a slippery slope of and loss of freedom from a mechanism that stamps every photo taken and silently cryptographically ties it to the photo taker. That could obviously be used for good or bad purposes. Reminds me of tracking dots in printers. It was implemented to provide a way to track a document to its source.
zbentley 5d ago
> a case where a normal person had genuine photos leaked and then just baldly denied everything "Genuine" is doing a lot of work in that sentence. A big part of the threat model for image provenance/signing/similarity diffing is identifying when images aren't genuine--if they're from elsewhere than they're claimed to be from, or have been modified. You're right that there are privacy/security costs to attributability, and that it's not always the right thing to do. I hope that keeping provenance information either entirely cryptographic in nature (okay, the image has a signature--you can't determine anything about that signature other than "signed with this key y/n" when you present a key) or reducing identifying or fingerprintable information presence in provenance metadata is sufficient to mitigate some of those concerns. Dr. Neal Krawetz has written and researched a lot about this topic: https://hackerfactor.com/blog/index.php?/archives/1069-The-Big-Bulleted-List.html https://hackerfactor.com/blog/index.php?/archives/1069-The-B... https://hackerfactor.com/blog/index.php?/archives/1098-Metas-Un-Stable-Signature.html https://hackerfactor.com/blog/index.php?/archives/1098-Metas... https://www.hackerfactor.com/blog/?/archives/529-Kind-of-Like-That.html https://www.hackerfactor.com/blog/?/archives/529-Kind-of-Lik...

smalltorch 5d ago

I don't think it's really the utility of deniability, rather a slippery slope of and loss of freedom from a mechanism that stamps every photo taken and silently cryptographically ties it to the photo taker. That could obviously be used for good or bad purposes. Reminds me of tracking dots in printers. It was implemented to provide a way to track a document to its source.

zbentley 5d ago

> a case where a normal person had genuine photos leaked and then just baldly denied everything "Genuine" is doing a lot of work in that sentence. A big part of the threat model for image provenance/signing/similarity diffing is identifying when images aren't genuine--if they're from elsewhere than they're claimed to be from, or have been modified. You're right that there are privacy/security costs to attributability, and that it's not always the right thing to do. I hope that keeping provenance information either entirely cryptographic in nature (okay, the image has a signature--you can't determine anything about that signature other than "signed with this key y/n" when you present a key) or reducing identifying or fingerprintable information presence in provenance metadata is sufficient to mitigate some of those concerns. Dr. Neal Krawetz has written and researched a lot about this topic: https://hackerfactor.com/blog/index.php?/archives/1069-The-Big-Bulleted-List.html https://hackerfactor.com/blog/index.php?/archives/1069-The-B... https://hackerfactor.com/blog/index.php?/archives/1098-Metas-Un-Stable-Signature.html https://hackerfactor.com/blog/index.php?/archives/1098-Metas... https://www.hackerfactor.com/blog/?/archives/529-Kind-of-Like-That.html https://www.hackerfactor.com/blog/?/archives/529-Kind-of-Lik...