| Picture: Nikon, C2 PA |
Last week, Nikon Released firmware v2.0 For Z6iii, which brought support for C2PA material credentials with many other characteristics. Theoretically, the cryptographic signature should prove that an image was authentically captured with the camera, and that has not been tampered with since its construction. However, the DPREVIEW Forum User Horsak has discovered a way to sign an image to the camera that was not actually taken.
You should do Check the thread Explanation of clarification for horns (well written, in general) explanation about how he did it. The summary is that it works using several exposure facilities of Z6iii. Nikon lets you choose a picture as your base, and then stack several exposure over it. Horoscope selected a raw image taken by another Z6ii, with content credential features enabled.
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This image, which is inhumanly created, has material credentials that claim that it was taken with Z6iii. Because it was… but only kind. |
He then took several exposure pictures with the lens cap. Results: The first unconscious image, now a material credential attached. If you put JPEG in adobe’s content credentials inspection tools, it appears to be a completely common image, signed as authentic by Z6iii.
Horoscope This trick will also work with a Z6ii raw file, which was revised to include, says, an AI-borne image. It is not necessary to fill another image in a raw file that you can do something with standard software, but horns believe that it can be done, allowing a signed file to remove an authentic image to obtain a signed file.
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| There is no information in the capture details section that the image was created by taking several exposures. |
The trick is not completely bulletproof. The Exif data of the image reports that it was created using multiple exposures, although Hornshack also discovered that you may be able to edit the metadata field of an image without invaliating the content credential. Some fields, such as the serial number of the camera, are stored within the credentials, but most are not.
We attempted to edit some metadata fields using EXIFTOOL, but we inspected the content credentials of Adobe as a result of each test, showing that it was no longer credentials.
I assumed that the images taken with the Nikon feature will not sign
Hornshack says that he discovered the issue that the content of the content credentials could fail. “When I thought about it, I assumed that I would not sign the images taken with the Nikon feature, which I to stop the results,” he said.
When Nikon announced the content credential feature for Z6iii, it classified it as beta, so Bugs were obliged to be. (In fact, horsak too Looks revealed that Why Some users Their cameras had to wait several hours before signing the images.) However, being able to use it to sign the images taken under different circumstances is a huge issue, one we hope that Nikon will hopes that Nikon will start as soon as possible.
We have reached Nikon for comment, and will update this story if we get any response.
