It's unclear exactly what this means to be honest. Which is not less scary but more.

This sentence:

> Next, iOS and iPadOS will use new applications of cryptography to help limit the spread of CSAM online

seems to suggest that the hash-matching happens only on iOS and iPadOS.

The rest of the text OTOH suggests many things happen across all types of devices and OSs.

Regardless, this seems very bad.

My guess is that they're going to put it into the macOS Photos app. Those images are already scanned for people, animals and objects so it should be easy for them to implement the child protection database there.

Won't implementing this on macOS make it too easy to reverse engineer? Think the hashes are supposed to be secret.

ETA: Apple quote: "unreadable set of hashes that is securely stored on users’ devices". Unreadable, unleakable, no doubt uninterpretable... unless someone reverses them to get a blurry 'visual proxy' collection.