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this post was submitted on 11 Feb 2024
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This doesn’t solve anything. The White House will only authenticate videos which make the President look good. Curated and carefully edited PR. Maybe the occasional press conference. The vast majority of content will not be authenticated. If anything this makes the problem worse, as it will give the President remit to claim videos which make them look bad are not authenticated and should therefore be distrusted.
It needs to be more general. A video should have multiple signatures. Each signature relies on the signer's reputation, which works both ways. It won't help those who don't care about their reputation, but will for those that do.
A photographer who passes off a fake photo as real will have their reputation hit, if they are caught out. The paper that published it will also take a hit. It's therefore in the paper's interest to figure out how trustworthy the supplier is.
I believe canon recently announced a camera that cryptographically signs photographs, at the point of creation. At that point, the photographer can prove the camera, the editor can prove the photographer, the paper can prove the editor, and the reader can prove the newspaper. If done right, the final viewer can also prove the whole chain, semi-independently. It won't be perfect (far from it) but might be the best will get. Each party wants to protect their reputation, and so has a vested interest in catching fraud.
For this to work, we need a reliable way to sign images multiple times, as well as (optionally) encode an edit history into it. We also need a quick way to match cryptographic keys to a public key.
An option to upload a time stamped key to a trusted 3rd party would also be of significant benefit. Ironically, Blockchain might actually be a good use for this. In case a trusted 3rd can't be established.
Great points and I agree. I also think the signature needs to be built into the stream in a continuous fashion so that snippets can still be authenticated.
Agreed. Embed a per-frame signature it into every key frame when encoding. Also include the video file time-stamp. This will mean any clip longer than around 1 second will include at least 1 signed frame.
Merkle tree hashes exists for this purpose
Note that videos uses "keyframes" so you can't extract arbitrary frames in isolation, you need to pull multiple if the frame you're snapshotting isn't a keyframe itself
I don't think that's practical or particularly desirable.
Today, when you buy something, EG a phone, the brand guarantees the quality of the product, and the seller guarantees the logistics chain (that it's unused, not stolen, not faked, not damaged in transport, ...). The typical buyer does not care about the parts used, the assembly factory, etc.
When a news source publishes media, they vouch for it. That's what they are paid for (as it were). If the final viewer is expected to check the chain, they are asked to do the job of skilled professionals for free. Do-your-own-research rarely works out, even for well-educated people. Besides, in important cases, the whole chain will not be public to protect sources.
It wouldn't be intended for day to day use. It's intended as a audit trail/chain of custody. Think of it more akin to a git history. As a user, you generally don't care, however it can be excellent for retrospective analysis, when someone/something does screw up.
You would obviously be able to strip it out, but having it as a default would be helpful with openness.
I've thought about this too but I'm not sure this would work. First you could hack the firmware of a cryptographically signed camera. I already read something about a camera like this that was hacked and the private key leaked. You could have an individual key for each camera and then revoke it maybe.
But you could also photograph a monitor or something like that, like a specifically altered camera lens.
Ultimately you'd probably need something like quantum entangled photon encoding to prove that the photons captured by the sensor were real photons and not fake photons. Like capturing a light field or capturing a spectrum of photons. Not sure if that is even remotely possible but it sounds cool haha.
Look up transparency logs for that last part, it's already used for TLS certificates
I don't understand your concern. Either it'll be signed White House footage or it won't. They have to sign all their footage otherwise there's no point to this. If it looks bad, don't release it.
The point is that if someone catches the President shagging kids, of course that footage won't be authenticated by the WH. We need a tool so that a genuine piece of footage of the Pres shagging kids would be authenticated, but a deepfake of the same would not. The WH is not a good arbiter since they are not independent.
But we are talking about official WH videos. Start signing those.
If it's not from the WH, it isn't signed. Or perhaps it's signed by whatever media company is behind its production or maybe they've verified the video and its source enough to sign it. So maybe, let's say the Washington Post can publish some compromising video of the President but it still has certain accountability as opposed to some completely random Internet video.
Politicians and anyone at deepfake risk wear a digital pendant at all times. Pendant displays continually rotating time-based codes. People record themselves using video hardware which crypto graphically signs output.
Only a law/Big 4 firm can extract video from the official camera (which has a twin for hot swapping).
Codes which don't embedd any information about what you're saying or doing can be copied over to faked images.
In theory you could have such a pendant record your voice, etc, and continously emit signatures for compressed versions of your speech (or a signed speech-to-text transcript)
Then this exercise is a waste of time. All the hard hitting journalism which presses the President and elicits a negative response will be unsigned, and will be distributed across social media as it is today: without authentication. All the videos for which the White House is concerned about authenticity will continue to circulate without any cause for contention.
Anyone can digitally sign anything (maybe not easily or for free). The Whitehouse can verify or not verify whatever they choose but if you, as a journalist let's say, want to give credence to video you distribute you'll want to digitally sign it. If a video switches hands several times without being signed it might as well have been cooked up by the last person that touched it.
That's fine?
Signatures aren't meant to prove authenticity. They're proving the source which you can use to weigh the authenticity.
I think the confusion comes from the fact that cryptographic signatures are mostly used in situations where proving the source is equivalent to proving authenticity. Proving a text message is from me proves the authenticity as there's no such thing as doctoring my own text message. There's more nuance when you're using signatures to prove a source which may or may not be providing trustworthy data. But there is value in at least knowing who provided the data.