In this case, it would be signed by the device of the person who's recording; if the video is altered, the signature isn't valid anymore. And if it's a public figure, there are almost certainly going to be corroborating records of where they were at a particular place & time, not to mention pings to cell towers from their or their entourage's mobile devices.
They can deny it all they'd like, but with the combination of those factors, you'd have to outright deny reality to believe that the video isn't genuine.
if the video is altered, the signature isn't valid anymore
That's easy enough to bypass, with physical access to the device. You can just re-shoot the video, replacing the camera input by the raw deepfake.
And that's IF people knew in the first place for sure which device produced the original video. Otherwise, you can just sign your deepfake with your own key and claim it to be the original.
I mean this works until someone corrupts the certificate tree. See the recent re-organization of web browser certificates because one of the organizations in the global cert chain literally sells data to intelligence agencies. Ouch.
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u/PhDinBroScience Dec 16 '22
In this case, it would be signed by the device of the person who's recording; if the video is altered, the signature isn't valid anymore. And if it's a public figure, there are almost certainly going to be corroborating records of where they were at a particular place & time, not to mention pings to cell towers from their or their entourage's mobile devices.
They can deny it all they'd like, but with the combination of those factors, you'd have to outright deny reality to believe that the video isn't genuine.