A perceptual hash set for scale/rotation/crop/colour invariant search? no. But that's presumably not all Facebook is doing and that is worrying. There isn't rea

A perceptual hash set for scale/rotation/crop/colour invariant search? no. But that's presumably not all Facebook is doing and that is worrying. There isn't really any reason for them to have direct access to the unblinded data - all they need to be able to do is ask "does this image description sound familiar? here app on phone, here's a more detailed extract of the questionable image and here's the reference... are they the same?". There is no reason for Facebook to request these images for unhashed upload unless they have an ulterior motive or are lazy.