Not OP, but personally I'd love to see this sort of tech baked directly into smartphones and cameras. Your camera could have tamper-proof hardware that embeds s

Not OP, but personally I'd love to see this sort of tech baked directly into smartphones and cameras. Your camera could have tamper-proof hardware that embeds signatures like you describe into the metadata of your video/photos while you take them. Sure, the user can separate it, but like you said over time people just won't trust photos/videos without this assurance. Apps like snapchat that let you apply filters could also add additional metadata, going through more hardware verified operations provided by things like Apple's secure enclaves, saying something like "X filter applied over frames N-M" and you can have an edit chain to go with the original video/photo. With this infrastructure in place our phones could really serve as ways to certify reality itself.