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Video integrity is an idea we have to let go of. Audio is robustly fakeable at this point, video is coming up to the threshold fast. What we can have is attest

Video integrity is an idea we have to let go of. Audio is robustly fakeable at this point, video is coming up to the threshold fast. What we can have is attestation and reputation, then provenance. It starts with a container format that allows signatures of both the entire video with audio, audio only, and video only, along with reasonable segments (three seconds?) of each of these. Excerpts of any of these can be transcluded into another such container. The editor can transform it in any way, the resulting display doesn't have to match the particulars of the excerpt (captioning, noise filtering, color correction) but the excerpt is itself included, or at least the signature. It would be useful for some people to have cameras which do this at the moment of recording, along with GPS, cell location data, and so on, to get really bulletproof documentary footage. I don't want that built into my phone, necessarily. As a container format and ffmpeg style tool, this would support anonymous attestation which can be demonstrated by the keyholder at any future time. As a built-in subpoena-able feature of my phone or mirrorless camera? Hmm, probably don't want that. If it snitches proactively, not a chance in hell.

HPsquared 4y ago
Even just a verifiable time stamp would be a big win.
- lvkv 4y ago
  One way to get a verifiable time stamp would be to show knowledge of an unpredictable but well-known thing in the past (providing a lower bound), then to create the same thing yourself (providing an upper bound). I wrote about it here: https://news.ycombinator.com/item?id=33558566 https://news.ycombinator.com/item?id=33558566. Your comment in particular made me feel like it was worth posting!
initplus 4y ago
Building attestation into hardware sounds like a good idea in theory, but doesn't actually work. All it tells you is "this is what the camera saw", it doesn't actually tell you that what the camera saw was real. You can just point your camera at a high resolution screen playing a doctored video, and so sign whatever doctored content you like. Or take a video of a real faked scene with actors.
- samatman 4y ago
  Of course it works, it works trivially. We mustn't confuse attestation with reputation, nor even the combination of attestation and reputation with truth. Attestation is nothing more than someone staking their reputation on the veracity of what they're sharing with the world. If I'm being frank, I thought this was too obvious to need stressing. If the camera is pointed at David Copperfield, cryptography can't make the lens show you reality. Attestation solves a lot of problems, but like my first sentence said, video integrity isn't a problem which can be solved anymore, if it ever was.
lvkv 4y ago
The trusted GPS problem might be solved by actually turning GPS upside down and having the device emit the signals instead of receiving them—it’s known as reverse or inverted GPS. I’ve written a blog post that addresses many of problems, and your comment was one of the reasons I posted it! You can find it at https://news.ycombinator.com/item?id=33558566 https://news.ycombinator.com/item?id=33558566

HPsquared 4y ago

Even just a verifiable time stamp would be a big win.

lvkv 4y ago
One way to get a verifiable time stamp would be to show knowledge of an unpredictable but well-known thing in the past (providing a lower bound), then to create the same thing yourself (providing an upper bound). I wrote about it here: https://news.ycombinator.com/item?id=33558566 https://news.ycombinator.com/item?id=33558566. Your comment in particular made me feel like it was worth posting!

initplus 4y ago

Building attestation into hardware sounds like a good idea in theory, but doesn't actually work. All it tells you is "this is what the camera saw", it doesn't actually tell you that what the camera saw was real. You can just point your camera at a high resolution screen playing a doctored video, and so sign whatever doctored content you like. Or take a video of a real faked scene with actors.

samatman 4y ago
Of course it works, it works trivially. We mustn't confuse attestation with reputation, nor even the combination of attestation and reputation with truth. Attestation is nothing more than someone staking their reputation on the veracity of what they're sharing with the world. If I'm being frank, I thought this was too obvious to need stressing. If the camera is pointed at David Copperfield, cryptography can't make the lens show you reality. Attestation solves a lot of problems, but like my first sentence said, video integrity isn't a problem which can be solved anymore, if it ever was.

lvkv 4y ago

The trusted GPS problem might be solved by actually turning GPS upside down and having the device emit the signals instead of receiving them—it’s known as reverse or inverted GPS. I’ve written a blog post that addresses many of problems, and your comment was one of the reasons I posted it! You can find it at https://news.ycombinator.com/item?id=33558566 https://news.ycombinator.com/item?id=33558566