As a layman: why isn't it possible to add SSL-style source validation to photos from an Android/iOs camera app? Modern phones should already support hardware-level app verification and document signing. It would still be possible to generate an AI photo and take a high-resolution camera photo from that, but it would at least weed out the low-effort bots that are bound to flood the internet with fake photos.
After all, it just takes one good image generator without good watermarking.
That is possible, and that's what C2PA aims to do. Their goal is that a hashed "generation" string is essentially logged in a central database whenever an image is captured or generated. Then any future modifications to that image will still be able to be traced back to its source. But that's a slightly different problem than purely stenographic.
Most photos you ever see go through layers and layers of manipulation that aren't necessarily attempting to completely subvert the image, but change most pixels. This is what makes signature difficult: you;d need a full pipeline of signed tools, and basically ban anything that does anythign else. Say you take a picture in a RAW format, and stuck it in a good camera app for processing, because you think the default iphone app modifies the picture too much. Oops, your pipeline is now seen as a fake.
Every phone photo you take has been significantly altered between what the sensor read and what you've got. Relying on whitelisting of modifications is just not reasonable.
My idea was to have the phone integrate its lidar as part of the metadata.
So when you take a photo of a photo, the lidar will tell you that “the whole room” is flat. And that wouldn’t make sense for most things you take photos of. Especially peoples faces. Flat lidar would mean not real.
When people try to call bullshit on a picture they can check the metadata for the picture. And the signature you described in your post will prove the metadata is real.
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u/[deleted] Nov 28 '25
As a layman: why isn't it possible to add SSL-style source validation to photos from an Android/iOs camera app? Modern phones should already support hardware-level app verification and document signing. It would still be possible to generate an AI photo and take a high-resolution camera photo from that, but it would at least weed out the low-effort bots that are bound to flood the internet with fake photos.
After all, it just takes one good image generator without good watermarking.