Nikon Suspends C2PA Functionality on the Z6 III Due to Authentication Issue

In response to a flaw with the Nikon Z6 III’s C2PA functionality, Nikon has suspended its Nikon Authenticity Service.

In a notice published today, September 5, Nikon confirmed that an issue with Nikon Authenticity Service has been identified.

“In response to this confirmation, the service has been temporarily suspended while we work diligently to resolve the issue,” Nikon says. “We will provide an update as soon as the corrective measures are complete. We sincerely apologize for any inconvenience this may have caused.”

Nikon does not describe or identify the issue in question, but it is almost certainly related to the fact that it is possible to combine C2PA-signed and unsigned photos into a single authenticated image file using the Z6 III’s Multiple Exposure mode.

As Nikon Z6 III owner Adam Horshack detailed following his own testing, he was able to get the Nikon Z6 III with firmware 2.0 to sign a photo that predominantly featured an image captured on his second Nikon Z6 III, which did not have C2PA functionality enabled.

As PetaPixel wrote yesterday, this loophole made it possible to capture a photo of anything, including AI-generated imagery, on a non-authenticated camera that would pass content credentials verification.

“The Z6 III can currently be used to capture and spread images with what are effectively false signatures,” PetaPixel wrote.


When PetaPixel contacted Nikon ahead of publication, the company said that an investigation was ongoing. Nikon’s team moved quickly to confirm that there is indeed an issue with the C2PA functionality in the Z6 III and reacted accordingly.

While this type of issue is never ideal, Nikon is at least acting quickly, which is always important, especially when concerning C2PA issues. The entire purpose of the Content Authenticity Initiative and its C2PA standards is to improve people’s trust in authenticated imagery, so anything that undermines that trust is a massive problem.

It remains unclear how Nikon will resolve the issue, but some potential options include locking down the Z6 III’s Multiple Exposure mode or even preventing images captured using the mode from being signed by the camera at all.

Image credits: Nikon and Adam Horshack. Header photo created using an asset licensed via Depositphotos.