"As part of developing the secure digital negative, PCC computes a confidence score that assesses whether the image has the physical characteristics expected of

"As part of developing the secure digital negative, PCC computes a confidence score that assesses whether the image has the physical characteristics expected of raw output from our camera sensors. Before the developed reference image is signed, PCC sends the photo GUID, sensor ID, and this confidence score to a companion service, which records them and updates the running score associated with that sensor." I wouldn't be surprised if it's also possible to detect the differences between a photo of a real scene and a photo of a monitor or printout displaying a photo of a real scene, given they have the raw sensor output. Not sure if they're doing anything like that.