I skimmed the whole article and I didn’t see a single image so I’m confused. Is there some watermark of some kind or where is this metadata integrated? Because if it’s just metadata then I need to parse each photo I come across manually, and if it’s a watermark it can be faked because I won’t manually validate every single image I come across to prove the watermark isn’t fake.
presumably the metadata reader app would be integrated into the photo viewer app which would verify the digital sigs.
I have my doubts about this scheme but this is not one of them. If the point is that someone in principle could verify, that is enough for it to be useful, even if not everyone does.