> You might be able to make a CCD chip that signs every frame with a private key, and then ships the frame off to a public signing server too. Producing that CCD along with the video taken might be proof. But then you could defeat that with a display hooked to the camera, feeding the doctored image to the trusted camera.
How does that defeat the cryptographic timestamping?
The goal is to have a video that can be used as evidence in court: what you're seeing actually happened. You can guarantee that the framebuffer recorded by the trusted camera is indeed an accurate recording of the photons that entered the lens.
But you still wouldn't be able to guarantee that that actually happened.. if we have enough compute and good enough algorithms, you could spoof a scene in real time on a small display strapped to the front of the trusted camera. Even though the trusted camera is recording what it sees, what it sees isn't really what is happening.
So we still don't get back to being able to use video as evidence.
How does that defeat the cryptographic timestamping?