It lets you prove a file was not modified after a certain point in time. So if you have two similar videos that are both timestamped you can prove which one is the original.
Link a blockchain app made with IOTA (for example, but this is the best and most manageable protocol I can see out there just now) to your unique ID in the form of something like your heartbeat plus your physical location plus your actual body shape, then perform a mini-transaction every 30 seconds or every minute or the granularity you need, finally store the transactions linked to that data as an alibi against any accusation that you were somewhere else doing something fake an AI created to blackmail you.
Or you could just be critical, and be aware of the limitations of media as it pertains to representation of truth and reality.
Besides, techniques for identifying fakes is likely to lag closely behind the techniques for producing them.
The first time we talked about "DeepFakes", someone I know pointed out that there is nothing inherently new in this issue. Media has been faked to manipulate the truth as long as there has been media.
Wether you trust the medium, a person, or a blockchain, trust is only as good as the information you base it upon – and there's always ways to circumvent it, or otherwise deceive you.
Also: There are some pretty big privacy issues (from what I understand) with what you describe.
Unbiased courts or at the very least your legacy as an innocent person if you get however smothered need a bullet proof you did not do what deepfakes claimed you did. As for privacy, again, blockchain makes your data fully available to you only and you only need to disclose the relevant bits against the time-space accusation you face. Trust cannot be delegated but reliable technical means would help a lot.
The courts should know that videos can be doctored, just as images can be photoshopped.
As the burden of proof lies with the accuser, it is they that would need a bullet proof argument that you did in face do what the video claims you did – and video is not alone in and of itself to establish truth.
As for the data gathering: the existence of the proposed data presents a threat for the subjects (and society) in and of itself.
IOTA wants to be so cheap with their machine-to-machine global aim that humans can be a quite limited subset of their full sample, making costs pretty thin. They may even allow it for free for a personal ID as a PR stunt to make the IOTA protocol mainstream.
> unique ID in the form of something like your heartbeat plus your physical location plus your actual body shape, then perform a mini-transaction every 30 seconds
Extreme surveillance, for what? To give evidence that you weren't in a fake dancing video?
Privacy first, so that you can disclose to third parties and to the general public at large the relevant and decentrally validated bits only, in pound-for-pound time and space contrast with any fake, AI-generated medium imho.
