[nicce]

There are already coming cameras which sign the data on the fly with help of hardware security modules. Only that can be truly verifiable.

Adding signature after recording works to certain degree, but it still does not guarantee that the content is what the camera saw.

[rhplus]

…what the camera saw.

Cameras can record screens.

Perhaps adding a signed channel for depth and/or non-visible light would be the next step.

[lazide]

Currently difficult to display something a modern smartphone camera will not be able to distinguish from real, right? (Pixel artifacts, lighting too consistent, etc. right?).

[squeaky-clean]

It might be doable with an 8k TV and a source video with a lens-distortion applied to generate the opposite expected lens distortion of the crypto camera, so once it's recorded the perspective does not look like it is a recording of a flat video. Depth sensors would help with defeating that idea.

Or you could just smear some Vaseline on the lens and tell people the lens got dirty. It hurts the credibility for anyone who knows about these cameras but I doubt the public would think about it that much.

[Horffupolde]

Yes but the idea is that you trust the camera which unique and works as a physical private key.

[tivert]

> Yes but the idea is that you trust the camera which unique and works as a physical private key.

You're pushing a (bad) technical solution to a social problem.

Cameras that cryptographically sign their output will not solve anything. The idea has more flaws than it's possible to list, but here's a big one: do you really think a technological gimmick like that would stand up to a nation state? Do you really think the CIA, NSA, FSB, Chinese Ministry of State Security, etc. will not be able to sign whatever the hell image they want with a camera's signature?

[14]

For sure but if they do it right it will make it hard enough and time consuming enough that only top actors can afford to do it.

[chromoblob]

Is that good, though? If a hole in a system is exploited by only "the top", it may be disregarded and "the top" will be able to inject anything there, but if it is exploitable by anyone from a wide group, then info from the system will be widely distrusted and communication may work around it?

Also, how to protect a chip from reverse engineering even from all except "top actors"? I remember the price for reverse engineering of certain ICs was between 5 and 7 figures of USD. Don't know about modern IC processes, but it may be affordable for many even for those?

[helsinkiandrew]

There's already things like eyeWitness (an app): https://www.eyewitness.global/

But even hardware can be hacked/bypassed if the effort is worth it.

[jacobsimon]

How would that work with video editing? Like if someone records something and then trims it for length or needs to combine multiple streams. Seems like hardware level verification only goes so far.

[nicce]

For editing it does not matter if you just remove or move frames. Video is just a series frames and each of them are signed, each frame can be validated if the content is unmodified. If the same root key is used for another stream, then frames can be combined easily.

I don't know audio well enough how it happens there. But potentially it can be signed in chunks as well.

Of course, one needs to consider risks if editing can make content appear different than originally intended, when the video as "whole" is not signed. But for that, different entity can be used again.

[rtkwe]

You do get into issues because video files aren't just raw frames and haven't been for ages. Plus any changes on top of the video wouldn't just pass the frames through beyond the fact that current video encoding would reencode the embedded video when the larger video it was embedded in was exported. You'd have to add support for seamless passthrough of the original frames so the signatures could be validated plus some additional layers if you wanted to enable having graphics on top of the footage.

It would require completely changing how software currently handles video editing in short.

[nicce]

Let's say that camera records in 60fps. Maybe all the data on all the channels can be recorded in chunks of 1/60s and signed separated. Then camera combines it as whole playable video, but then there is a separate metadata for each time/byte offset which have been signed.

At the beginning, camera manufacturers might need to provide their own editors, to make editing possible. How much we can trust the camera holders, if the editor software even allows using the key from the camera for better editing in certain limits?

[rtkwe]

Intraframe compression where each frame is individually compressed is barely used any more outside of movies and other professional nonsteamed production because it barely compresses the resulting video. Most streaming and consumer video cameras use interframe compression where you get a full frame every few frames and the rest are moving pieces of that around. This video by Captain Disillusion [0] goes over it much better than I can and any time the video is edited it goes through that process again of creating I-frames P-frames and whatever new homunculus frames are invented to further compress video while maintaining quality.

If you just cut away to the original clip and didn't have any modifications like motion graphics over the top of it you could in theory pass through the original video with the same compression and signing without too much drama but any modifications over that or presenting it as picture in picture would be a big difference as now you need to have both the original frames with the added graphics on top.

[0] https://youtu.be/flBfxNTUIns?t=139

[aqme28]

> video files aren't just raw frames and haven't been for ages.

Does that really matter? You could sign keyframes, and then also sign the differences frame by frame til you get to the next keyframe.

[rtkwe]

You could but then that only really works for rehosting the exact same video. Most places would at least embed it in another video for commentary which would have a reencoding step that would wipe out the original video. See my other comments for more detail but it would require changing how we handle videos to preserve the signing info.

[aqme28]

That's a problem with embedding then, not with compression, right? Would embedding a raw video with commentary not also have the same problem?

[artursapek]

Really?? I imagined this product but thought there must be some reason it’s a bad idea

[yomlica8]

It could be used to hunt down reporters and whistleblowers if the cameras have to be purchased with an ID. So the very people who would benefit might be forced to strip this extra data to protect themselves.

I wonder if you could use the camera to record deepfaked video and in effect bless a lie. Even just filming a TV set might be enough for low grade blackmail and much more complicated methods are available.

[rtkwe]

At least as a start after the fact signing will say this video was released by X.

[wredue]

Can’t wait for the first political misstep being blamed on leaked keys.