Wow! Another incredible consequence of this tech is that it will actually make blockchain based confirmations of unadulterated digital assests a valuable and needed service as the amount of well crafted fakes soars exponentially. A service that I didn’t see having a big amount of market potential now seems essential.
This point has come up a lot in earlier discussions; the short summary of it is that signatures/blockchains/whatever can't provide anything useful in this regard.
I really don't want to repeat all of this here, but in essence: (1) you'd need all (and I mean all, not most; so all the currently existing devices need to be replaced) of devices that can capture video (and thus can sign/confirm the thing that they captured) to be fully outside of user control, if 0.01% of devices are jailbroken, it fails; (2) you'd need all the manufacturers of such devices (which put the appropriate secrets in the devices) and all the supply chain in between to be 100% trustworthy, since if a manufacturer gives 100 phones to a spy agency that'll happily sign anything as "unadulterated" then it fails; (3) you'd need to figure out a magic way to prevent the analog loophole, as with specialized expensive optics you could project arbitrary pixels to the camera sensor so that the camera would "believe" that it's seeing the exact pixels in reality.
A blockchain would allow you to securely assert things like "this data was seen and signed by device #1234/(or approved by user id #456) no later than this moment", and not more than that. It can't really prove that this data reflects reality somehow; a physical device that has the technical ability to take a picture of my face and add a "it's unadulterated" tag to it can be used (with appropriate effort) to take a fake AI-generated picture and add the same "it's unadulterated" tag.
I still think this coming despite all of the reasonable limitations you listed. Our society will desire some form of authenticity and I can imagine an alliance of companies coming together to provide that.
