Imagine you were alive at the time Noah was building the Ark. You had a video camera. However, the special thing about this camera is it can only see giraffes. You sit (high up) on the side of a nearby mountain filming all the animals as they march into the Ark but at the end of the day the record will show only two giraffes went on board. All the other animals were invisible to the camera. So, assuming you had not obtained the prior consent of the giraffes to them being filmed they might have a reasonable complaint that their right to privacy had been violated in relation to their participation in the Ark Project. After all, getting on to a life-saving ship is not a crime nor is it in any other way problematic. Now think about how photoDNA works. If the only thing the algorithm can do is see material that has already been determined to be csam, how can anyone complain that this is unlawful or improper surveillance? It isn’t. It is child protection.