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You're not thinking this through. The problem isn't that creators can make fake videos (which would be analogous to DRM). Let them. There is no harm in it. The

You're not thinking this through. The problem isn't that creators can make fake videos (which would be analogous to DRM). Let them. There is no harm in it. The problem is that users have no way of verifying true videos. This can be solved with cryptography, because both parties involved (creators and viewers) would want this to work. In other words, DRM is about forcing everyone to do a thing. Verification is about allowing willing participants to check a thing. Different scenarios. Companies could make tamper-proof sensor modules that do the signing right where it matters. The important thing is to make sure they aren't astronomically priced and don't compromise privacy.

anbop 7y ago
Play deepfake on a TV, point signed camera at it.
- gambler 7y ago
  Have you ever tried this? The quality will be awful. As far as I'm concerned, the need to use a real camera to capture real light is sufficient to thwart creation of truly convincing fakes.
  - jdietrich 7y ago
    >Have you ever tried this? Yes. It used to be the industry standard method for recording TV programmes prior to the invention of videotape recorders. If you know what you're doing and use the right equipment, the generational quality loss is very minor. https://en.wikipedia.org/wiki/Kinescope https://en.wikipedia.org/wiki/Kinescope
    - gambler 7y ago
      >It used to be the industry standard method for recording TV programmes prior to the invention of videotape recorders. Back when everything was analog and low-resolution, had noise and artifacts anyway, sure. Do you have a video that compares modern digital 1080p with its best "Kinescoped" version? You have to deal with parallax, mismatched frame frequencies, pixels and differences between natural light and whatever spectrum the source monitor produces. I have never seen a recording of a screen that looked anywhere close in quality to the original in 1080p.
      - buildzr 7y ago
        We're talking about faked videos here though, often of things where the quality is already quite questionable. If it shows something that looks 480p good enough and gets the green checkmark it's game over for this concept of video verification. No one needs perfect 1080p or 4k video to believe politician or celebrity is sleeping around. If it gets it to the point where it takes years of experience with this to figure out what is and isn't fake... I doubt that's any better than the situation without such a video verification system at all. In fact, I'd argue it's worse due to the fake seal of approval being given to the video.
      - taneq 7y ago
        > Do you have a video that compares modern digital 1080p with its best "Kinescoped" version? As an informal comparison, check out a downloaded "cam version" of any recent movie compared with a DVD rip. If you ignore the occasional noise or interference from the crowd, the quality can be quite good.
- neuronexmachina 7y ago
  I think the point of cryptographic signing wouldn't be verifying that it was recorded with a camera, but that it was recorded with a specific camera.
  - cwkoss 7y ago
    I wonder if future studio cameras will need water cooling lines to dissipate the crypto heat
- petters 7y ago
  You can have the camera record metadata as well, like focus settings and super speed. That will make it harder.
  - fwip 7y ago
    And you can build a camera that lies about this.
    - buildzr 7y ago
      Not quite as you can't necessarily clone the keys from an existing camera without some difficulty, however you can say, replace those sensors with your own inputs fed using a cheap microcontroller you wrote the firmware for. There's a time and effort investment but it's not exactly high...
    - vokep 7y ago
      True, but today you also can hire a lookalike to some target person and record footage of them doing something terrible, or edit footage carefully enough that the edit cannot be detected. Deepfake makes it less expensive to create fake video of someone, special signing cameras could make it expensive again in the face of that.
deleted 7y ago
[deleted]
jdietrich 7y ago
I'm sorry, but you're not thinking this through. Being able to prove that a video file is the unaltered output of a particular camera is in no way a useful protection against fake videos. Proving that file A is genuine tells us nothing about whether file B is fake. Let's say I want to create and circulate a fake sex tape featuring a senior politician. In a world where signed sensors are common but not mandatory, the absence of a signature says nothing at all about the integrity of my video - there are still millions of cameras in the world that produce unsigned files. In a world where they are mandatory, I can simply fake the video in software and then re-record it using a high-resolution display and a signed sensor. A digital video expert might be able to prove that such a re-recording process took place, but I highly doubt that they'd be able to say so with any degree of confidence if there's a bunch of sensor noise and a couple of rounds of low-bitrate transcoding. Signed sensors won't do anything to undermine the credibility of fake videos, but they may have the opposite effect if they're hacked - I can "prove" that my deepfake is genuine, because I've extracted a signing key or injected a bitstream into a camera module. https://www.forbes.com/sites/kalevleetaru/2018/09/09/why-digital-signatures-wont-prevent-deep-fakes-but-will-help-repressive-governments/ https://www.forbes.com/sites/kalevleetaru/2018/09/09/why-dig...
- deckar01 7y ago
  You don't need to be able to prove the video is raw footage, you just need to be able to verify that a publisher you trust says they recorded it. An HMAC allows you to verify that a message (like a video file) was not modified after the author signed it.
  - buildzr 7y ago
    I was under the impression that the whole point of such a system was you could trust any video from any (non-cracked) camera. If we're at the point of trusting videos only from select providers, well, that's not really much of an improvement over just finding the video on that provider's website over HTTPS.
  - jdietrich 7y ago
    Hypothetical: An anonymous source releases CCTV footage that appears to show a public figure urinating on a homeless person. Do you really believe that we'll all ignore that footage because the signature doesn't belong to a major news organisation?
ajuc 7y ago
There's a video of a politician taking a bribe. How do you verify it's real? You can't - because the camera of the guy that published it says it's not modified, but it could be just as well a camera recording a display with the fake playing.
- bdamm 7y ago
  Cameras recording displays also leave artifacts in the resulting stream. There would at the very least likely be a moire pattern somewhere, at some level, and somehow the capturing camera would need to resolve that. That resolution will leave a fingerprint.
  - evan_ 7y ago
    “I work at a hotel and $politician came in with his mistress. Here’s a video I taped off of the security monitor.”
    - buildzr 7y ago
      That's actually an excellent point, even if such technology worked perfectly it wouldn't solve simple problems like that. Seeing footage literally taped by a phone off a NVR display is pretty common...
      - bdamm 7y ago
        Yeah, but it also is usually pretty obvious about what it is. That's hard to cover up.
        buildzr 7y ago
        It's actually not too bad - you have to essentially line up the pixels on the camera's sensor with the pixels on the display, it's a challenge and might involve some careful choices of camera, display, focal length, distance, etc, but you only have to get it right once. This gets even easier with a projector where pixels can be blended together, that's why cam'd movies can be surprisingly watchable, despite being filmed in far less than optimal conditions, they don't show the sort of artifacts you're talking about. While poor contrast can certainly be an issue in such situations, think about how poor that setup is compared to what would be possible with a purpose built version.
dang 7y ago
> You're not thinking this through. Would you please edit swipes like that (and "you must live in a parallel universe, to put it politely") out of your comments here? They break the guidelines, lower the signal/noise ratio, and invite more of the same from others. Your comments would be just fine without those bits. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
- deleted 7y ago
  [deleted]
jobigoud 7y ago
> Companies could make tamper-proof sensor modules that do the signing right where it matters. Just film a screen displaying the fake video. As soon as it's possible for a bad actor to create signed fake content it invalidates the entire protocol. Oh, ok, I see what you mean now. The viewer already trusts the creators, so the threat model is not about an attacker creating fake videos. But if you already trust the creator why do you need further proof? Identity is already solved. The problem at stake here is videos released to the general public where the source is unknown, or not trusted by all stakeholders, i.e, during a trial.
darepublic 7y ago
To play devil's advocate, video evidence is already not very strong. Can't it already be faked enough without this technology such that we should never trust it as irrefutable proof of anything

anbop 7y ago

Play deepfake on a TV, point signed camera at it.

gambler 7y ago
Have you ever tried this? The quality will be awful. As far as I'm concerned, the need to use a real camera to capture real light is sufficient to thwart creation of truly convincing fakes.
- jdietrich 7y ago
  >Have you ever tried this? Yes. It used to be the industry standard method for recording TV programmes prior to the invention of videotape recorders. If you know what you're doing and use the right equipment, the generational quality loss is very minor. https://en.wikipedia.org/wiki/Kinescope https://en.wikipedia.org/wiki/Kinescope
  - gambler 7y ago
    >It used to be the industry standard method for recording TV programmes prior to the invention of videotape recorders. Back when everything was analog and low-resolution, had noise and artifacts anyway, sure. Do you have a video that compares modern digital 1080p with its best "Kinescoped" version? You have to deal with parallax, mismatched frame frequencies, pixels and differences between natural light and whatever spectrum the source monitor produces. I have never seen a recording of a screen that looked anywhere close in quality to the original in 1080p.
    - buildzr 7y ago
      We're talking about faked videos here though, often of things where the quality is already quite questionable. If it shows something that looks 480p good enough and gets the green checkmark it's game over for this concept of video verification. No one needs perfect 1080p or 4k video to believe politician or celebrity is sleeping around. If it gets it to the point where it takes years of experience with this to figure out what is and isn't fake... I doubt that's any better than the situation without such a video verification system at all. In fact, I'd argue it's worse due to the fake seal of approval being given to the video.
    - taneq 7y ago
      > Do you have a video that compares modern digital 1080p with its best "Kinescoped" version? As an informal comparison, check out a downloaded "cam version" of any recent movie compared with a DVD rip. If you ignore the occasional noise or interference from the crowd, the quality can be quite good.
neuronexmachina 7y ago
I think the point of cryptographic signing wouldn't be verifying that it was recorded with a camera, but that it was recorded with a specific camera.
- cwkoss 7y ago
  I wonder if future studio cameras will need water cooling lines to dissipate the crypto heat
petters 7y ago
You can have the camera record metadata as well, like focus settings and super speed. That will make it harder.
- fwip 7y ago
  And you can build a camera that lies about this.
  - buildzr 7y ago
    Not quite as you can't necessarily clone the keys from an existing camera without some difficulty, however you can say, replace those sensors with your own inputs fed using a cheap microcontroller you wrote the firmware for. There's a time and effort investment but it's not exactly high...
  - vokep 7y ago
    True, but today you also can hire a lookalike to some target person and record footage of them doing something terrible, or edit footage carefully enough that the edit cannot be detected. Deepfake makes it less expensive to create fake video of someone, special signing cameras could make it expensive again in the face of that.

deleted 7y ago

[deleted]

jdietrich 7y ago

I'm sorry, but you're not thinking this through. Being able to prove that a video file is the unaltered output of a particular camera is in no way a useful protection against fake videos. Proving that file A is genuine tells us nothing about whether file B is fake. Let's say I want to create and circulate a fake sex tape featuring a senior politician. In a world where signed sensors are common but not mandatory, the absence of a signature says nothing at all about the integrity of my video - there are still millions of cameras in the world that produce unsigned files. In a world where they are mandatory, I can simply fake the video in software and then re-record it using a high-resolution display and a signed sensor. A digital video expert might be able to prove that such a re-recording process took place, but I highly doubt that they'd be able to say so with any degree of confidence if there's a bunch of sensor noise and a couple of rounds of low-bitrate transcoding. Signed sensors won't do anything to undermine the credibility of fake videos, but they may have the opposite effect if they're hacked - I can "prove" that my deepfake is genuine, because I've extracted a signing key or injected a bitstream into a camera module. https://www.forbes.com/sites/kalevleetaru/2018/09/09/why-digital-signatures-wont-prevent-deep-fakes-but-will-help-repressive-governments/ https://www.forbes.com/sites/kalevleetaru/2018/09/09/why-dig...

deckar01 7y ago
You don't need to be able to prove the video is raw footage, you just need to be able to verify that a publisher you trust says they recorded it. An HMAC allows you to verify that a message (like a video file) was not modified after the author signed it.
- buildzr 7y ago
  I was under the impression that the whole point of such a system was you could trust any video from any (non-cracked) camera. If we're at the point of trusting videos only from select providers, well, that's not really much of an improvement over just finding the video on that provider's website over HTTPS.
- jdietrich 7y ago
  Hypothetical: An anonymous source releases CCTV footage that appears to show a public figure urinating on a homeless person. Do you really believe that we'll all ignore that footage because the signature doesn't belong to a major news organisation?

ajuc 7y ago

There's a video of a politician taking a bribe. How do you verify it's real? You can't - because the camera of the guy that published it says it's not modified, but it could be just as well a camera recording a display with the fake playing.

bdamm 7y ago
Cameras recording displays also leave artifacts in the resulting stream. There would at the very least likely be a moire pattern somewhere, at some level, and somehow the capturing camera would need to resolve that. That resolution will leave a fingerprint.
- evan_ 7y ago
  “I work at a hotel and $politician came in with his mistress. Here’s a video I taped off of the security monitor.”
  - buildzr 7y ago
    That's actually an excellent point, even if such technology worked perfectly it wouldn't solve simple problems like that. Seeing footage literally taped by a phone off a NVR display is pretty common...
    - bdamm 7y ago
      Yeah, but it also is usually pretty obvious about what it is. That's hard to cover up.
      - buildzr 7y ago
        It's actually not too bad - you have to essentially line up the pixels on the camera's sensor with the pixels on the display, it's a challenge and might involve some careful choices of camera, display, focal length, distance, etc, but you only have to get it right once. This gets even easier with a projector where pixels can be blended together, that's why cam'd movies can be surprisingly watchable, despite being filmed in far less than optimal conditions, they don't show the sort of artifacts you're talking about. While poor contrast can certainly be an issue in such situations, think about how poor that setup is compared to what would be possible with a purpose built version.

dang 7y ago

> You're not thinking this through. Would you please edit swipes like that (and "you must live in a parallel universe, to put it politely") out of your comments here? They break the guidelines, lower the signal/noise ratio, and invite more of the same from others. Your comments would be just fine without those bits. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html

deleted 7y ago
[deleted]

jobigoud 7y ago

> Companies could make tamper-proof sensor modules that do the signing right where it matters. Just film a screen displaying the fake video. As soon as it's possible for a bad actor to create signed fake content it invalidates the entire protocol. Oh, ok, I see what you mean now. The viewer already trusts the creators, so the threat model is not about an attacker creating fake videos. But if you already trust the creator why do you need further proof? Identity is already solved. The problem at stake here is videos released to the general public where the source is unknown, or not trusted by all stakeholders, i.e, during a trial.

darepublic 7y ago

To play devil's advocate, video evidence is already not very strong. Can't it already be faked enough without this technology such that we should never trust it as irrefutable proof of anything