> And so what if you sign the EXIF data. That only really guarantees that version of the image. If you adjust the saturation or curves or exposure... or correct for some lens aberration does that EXIF information still match the resulting photo? For that matter, what if you crop it to a square from a rectangle or stitch two images into a panorama?
Oh, that's actually possible with cryptographic techniques. Very exciting!
Those are interesting, but there's a difference in the manipulations that are done for image for journalism and image for art. That has crop, resize, and grayscale... but not things like "selectively dodge and burn", "adjust the white balance", "skew or rotate to level horizon", or "correct for chromatic and coma aberration in a particular lens."
While that is good and useful (and I would be willing to even go so far as saying "needed" for journalistic uses), the transformations available are remarkably limited for artistic use that even represent what can be done in a traditional darkroom.
Oh, that's actually possible with cryptographic techniques. Very exciting!
See eg https://medium.com/@boneh/using-zk-proofs-to-fight-disinform... or http://www.cs.tau.ac.il/~tromer/papers/photoproof-oakland16....
Of course, the analog hole stays wide open.