The problem with that is, the video can only be watched at it's true raw form. Any edits will need to be re-signed with "Edited by X". Now, X has to be trusted and not compromised (by money, bias or hacks).

If X is CNN, then half the population will not believe it. If X is Fox, the other half won't believe. Bottomline, the world will be truly living in virtual alternative universes and it doesn't even matter what truth is as long as everyone in that world believe that.

Watching and verifying are two separate procedures, if the edited piece has a link to the original source, the verification can pass to that.

This is actually a valid use case of blockchain, where each edit is signed by an entity in cascading fashion.

> Build keys into sensors to sign media and use something like blockchain to broadcast the signature at time of capture / time when the device returns to the internet.

That literally accomplishes nothing. It would be a matter of time before someone just removes the light sensor (CCD? or something) and has a custom made encoder that can write the input data as though the device actually records it live.

Yes, like I said, it's not perfect. There will still be deepfakes, but they won't be around every single nook and cranny. And once you ever invalidate a video, all other works by the same key are now suspect.

Imagine two court cases. In one, there is a video signed with a key from a phone that shows no signs of compromise. In the other, there is a video with no signatures at all. Which is more trustworthy? It's a continuum, not a binary.

Edit:

And also, we can scale trust. There should be more webs-of-trust in the world. I should be able to tap my phone next to my buddies and it should create a link between us. We should have the concept of trust online when we need it.