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If it were generally possible to forge cryptographic signatures we'd have bigger things to worry about than AI generated photos.

chrisjj 2mo ago
I agree, but this doesn't require a general capability. The suggestion is a camera could apply the signature. Cameras could be hacked.
- hamdingers 2mo ago
  A camera could be hacked with unrestricted physical access, but that doesn't make the suggestion unsound, it only requires there be a process for revoking trust in specific signing keys. This is already part of C2PA. And the value of the signature is also going to vary by who claims it. Improbable photos signed by a random camera body sold to an anonymous consumer should be treated with more suspicion than one a newswire agency publicly claims, for instance.
- jfyi 2mo ago
  A camera should not need to be hacked. What do you expect to accomplish by hacking the camera? We should be able to move certificates on and off it because they would most likely expire anyway. So, you can get the keys from the camera, what then? You use openssl to sign an image that shouldn't be signed... what then? You do this enough and get caught, you lose your cert and can never pass the kyc to get another one. Then every picture you used it for in the past would start showing a big red exclamation point with a note, "This is a scumbag user known for forging images".
  - chrisjj 2mo ago
    > You use openssl to sign an image that shouldn't be signed... what then? You do whatever you want with your provably genuine fake image. > You do this enough and get caught How are you going to get caught? By the signature owner repudiating some of the images "he" signed? I can see that working out for him.
    - jfyi 2mo ago
      Same way it works for tls and code signing. Public reports bad actors to the signing authority. They and/or independent firms investigate. You self report theft. It's not like we are inventing pki from scratch here and wondering what an implementation would look like. We have decades of use to look at. Besides wasn't your argument "hacking" a minute ago? So you concede that then? You seem to have moved on.
      - chrisjj 2mo ago
        > Public reports bad actors to the signing authority. Public would know the pics were fake let alone know who to report. > They and/or independent firms investigate. What's to investigate? You have a fake pic that is indistinguishable from genuine and "proved" by a sig.
        jfyi 2mo ago
        Yes, "the public" includes experts in the subject field and independent witnesses to events. If your argument is that images can't be verified, you are going to need to provide some kind of backing to that. We know well that there are watermarks and tell tale signs to go off. Regardless, if they are depicting real world events, outside confirmation can be used. You also don't seem to understand the point of the signature. It's not to prevent fake images, it's to tie an identity to images so that that trust can be established and permanently lost in the case of a malicious actor. Your arguments repeatedly have failed to engage with the actual system proposed.
        chrisjj 2mo ago
        > You also don't seem to understand the point of the signature. It's not to prevent fake images, it's to tie an identity to images so that that trust can be established and permanently lost in the case of a malicious actor. It was proposed as a solution to: how is any future viewer going to tell your images from "AI" fakes? You seem to be saying it is not a solution. I agree.

chrisjj 2mo ago

I agree, but this doesn't require a general capability. The suggestion is a camera could apply the signature. Cameras could be hacked.

hamdingers 2mo ago
A camera could be hacked with unrestricted physical access, but that doesn't make the suggestion unsound, it only requires there be a process for revoking trust in specific signing keys. This is already part of C2PA. And the value of the signature is also going to vary by who claims it. Improbable photos signed by a random camera body sold to an anonymous consumer should be treated with more suspicion than one a newswire agency publicly claims, for instance.
jfyi 2mo ago
A camera should not need to be hacked. What do you expect to accomplish by hacking the camera? We should be able to move certificates on and off it because they would most likely expire anyway. So, you can get the keys from the camera, what then? You use openssl to sign an image that shouldn't be signed... what then? You do this enough and get caught, you lose your cert and can never pass the kyc to get another one. Then every picture you used it for in the past would start showing a big red exclamation point with a note, "This is a scumbag user known for forging images".
- chrisjj 2mo ago
  > You use openssl to sign an image that shouldn't be signed... what then? You do whatever you want with your provably genuine fake image. > You do this enough and get caught How are you going to get caught? By the signature owner repudiating some of the images "he" signed? I can see that working out for him.
  - jfyi 2mo ago
    Same way it works for tls and code signing. Public reports bad actors to the signing authority. They and/or independent firms investigate. You self report theft. It's not like we are inventing pki from scratch here and wondering what an implementation would look like. We have decades of use to look at. Besides wasn't your argument "hacking" a minute ago? So you concede that then? You seem to have moved on.
    - chrisjj 2mo ago
      > Public reports bad actors to the signing authority. Public would know the pics were fake let alone know who to report. > They and/or independent firms investigate. What's to investigate? You have a fake pic that is indistinguishable from genuine and "proved" by a sig.
      - jfyi 2mo ago
        Yes, "the public" includes experts in the subject field and independent witnesses to events. If your argument is that images can't be verified, you are going to need to provide some kind of backing to that. We know well that there are watermarks and tell tale signs to go off. Regardless, if they are depicting real world events, outside confirmation can be used. You also don't seem to understand the point of the signature. It's not to prevent fake images, it's to tie an identity to images so that that trust can be established and permanently lost in the case of a malicious actor. Your arguments repeatedly have failed to engage with the actual system proposed.
        chrisjj 2mo ago
        > You also don't seem to understand the point of the signature. It's not to prevent fake images, it's to tie an identity to images so that that trust can be established and permanently lost in the case of a malicious actor. It was proposed as a solution to: how is any future viewer going to tell your images from "AI" fakes? You seem to be saying it is not a solution. I agree.