They might use complicated tech because things are changing due to AI in a way that could degrade their brands trust. By having camera-signed videos, when folks create eg deep fakes of their news anchors/brands, there's a way for consumers to verify what's real. It lets their brands become more trustworthy.
Yeah, preserving the chain of custody is hard. I was thinking there are a few options: (1) the signature of the original video could be attached even after editing/compression, and then a news org would let you look up the signature. That way if someone copied the signature and stuck it on a fake video, you could see the original video that actually passes with that signature, and determine if something has been doctored. Or (2), you could have editing software add a signature verifying the edits made: eg compression, rescaling etc.
And then a law to make it illegal to remove/tamper/valsify a signature, like we have for DVDs, to allow some form of prosecution. The hardware stack is a little easier to protect; the software stack less so. But if we can do it with things like eg browser DRM or http signatures, maybe we can with media editing software? But I'm not versed enough in Cryptography to really know.
And cool will read up on intel SGX, thanks!