You may be able to prove that a photo with certain metadata was taken by a camera (my understanding is that that’s the method), but you can’t prove that a photo without it wasn’t, because older cameras won’t have the necessary support, and wiping metadata is trivial anyway. So is it better to have more false negatives than false positives? Maybe. My suspicion is that it won’t make much difference to most people.
A fair few sites will also wipe image/EXIF metadata for safety reasons, since photo metadata can include things like the location where the photo was taken.
Even if you assume the images you care about have this metadata, all it takes is a hacked camera (which could be as simple as carefully taking a photo of your AI-generated image) to fake authenticity.
And the vast majority of images you see online are heavily compressed so it’s not 6MB+ per image for the digitally signed raw images.
It’s not that simple. It’s not just a “this is or isn’t AI” boolean in the metadata. Hash the image, then sign the hash with digital signature key. The signature will be invalid if the image has been tampered with, and you can’t make a new signature without the signing key.
Once the image is signed, you can’t tamper with it and get away with it.
The vulnerability is, how do you ensure an image isn’t faked before it gets to the signature part? On some level, I think this is a fundamentally unsolvable problem. But there may be ways to make it practically impossible to fake, at least for the average user without highly advanced resources.
Cameras don’t cryptographically sign the images they take. Even if that was added, there are billions of cameras in use that don’t support signing the images. Also, any sort of editing, resizing, or reencoding would make that signature invalid. Almost no one is going to post pictures to the web without any sort of editing. Embedding 10+ MB images in a web page is not practical.
You may be able to prove that a photo with certain metadata was taken by a camera (my understanding is that that’s the method), but you can’t prove that a photo without it wasn’t, because older cameras won’t have the necessary support, and wiping metadata is trivial anyway. So is it better to have more false negatives than false positives? Maybe. My suspicion is that it won’t make much difference to most people.
A fair few sites will also wipe image/EXIF metadata for safety reasons, since photo metadata can include things like the location where the photo was taken.
Even if you assume the images you care about have this metadata, all it takes is a hacked camera (which could be as simple as carefully taking a photo of your AI-generated image) to fake authenticity.
And the vast majority of images you see online are heavily compressed so it’s not 6MB+ per image for the digitally signed raw images.
You don’t even need a hacked camera to edit the metadata, you just need exiftool.
It’s not that simple. It’s not just a “this is or isn’t AI” boolean in the metadata. Hash the image, then sign the hash with digital signature key. The signature will be invalid if the image has been tampered with, and you can’t make a new signature without the signing key.
Once the image is signed, you can’t tamper with it and get away with it.
The vulnerability is, how do you ensure an image isn’t faked before it gets to the signature part? On some level, I think this is a fundamentally unsolvable problem. But there may be ways to make it practically impossible to fake, at least for the average user without highly advanced resources.
Cameras don’t cryptographically sign the images they take. Even if that was added, there are billions of cameras in use that don’t support signing the images. Also, any sort of editing, resizing, or reencoding would make that signature invalid. Almost no one is going to post pictures to the web without any sort of editing. Embedding 10+ MB images in a web page is not practical.
We aren’t talking about current cameras. We are talking about the proposed plan to make cameras that do cryptographically sign the images they take.
Here’s the link from the start of the thread:
https://arstechnica.com/information-technology/2024/09/google-seeks-authenticity-in-the-age-of-ai-with-new-content-labeling-system
This system is specifically mentioned in the original post: https://www.seroundtable.com/google-search-image-labels-ai-edited-38082.html when they say “C2PA”.