Comment by graypegg

To be fair, I think just signing details about the way an image was assembled makes sense. Deciding on fake vs real doesn't have to be done at time of capture. We store things like the aperture size, sensitivity, camera name/model, etc in the EXIF data, including details about the image processing pipeline seems like a logical step. (With a signature verification scheme... and I guess also trying to embed that in the actual bitmap data)

There is no original image to recover, since we can't capture and describe every photon, so it's not a "fake vs real" image signature... that would be a UI choice the image viewer client would make based on the pipeline data in the image.