I don't know. I don't want to live in a world where someone can literally murder someone on camera and get away with it on a technicality. Witness testimony is already used in court and is quite unverifiable and subject to all sorts of psychological phenomenon where people sometimes believe they saw something entirely different than what actually happened. I think cryptographic signatures couldn't guarantee validity 100%, but they could improve the situation in a world of deep fakes on demand.
It would require a larger degree of premeditation and effort to convincingly pull off a deep fake in that world.
It's not a technicality if the video can't be distinguished from perfect nonsense. Just as you don't let someone with a documented history of hallucinations testify on their own.
It would require a larger degree of premeditation and effort to convincingly pull off a deep fake in that world.