Do you have a link?
It's only on their servers that they will do the check against the database of CSAM content. So in that sense, it's pretty much the same that what other providers do, it remains attached to their online service, and they check the hash against the database instead of checking the picture (as others do).
If you don't use their iCloud service, the hash is never checked.
I still don't think having the client as part of the system is a good thing, but in terms of abuse it's about the same thing.
What Apple's system allow is a way to do a check while keeping the data encrypted in some 3rd party service. That part certainly raises questions should it be extended.
> "He was trying to get around getting caught, he was trying to keep it inside his email," said Detective David Nettles of the Houston Metro Internet Crimes Against Children Taskforce reports the station. "I can't see that information, I can't see that photo, but Google can."
"email" here is presumably Gmail, which Google owns and is responsible for. The dude was storing illegal data on Google servers in plain form. His personal devices were only checked by LEOs after a warrant was issued. Definitely not the same as Apple scanning the images on your device (not their servers).
https://www.apple.com/child-safety/pdf/Expanded_Protections_...
> This feature only impacts users who have chosen to use iCloud Photos to store their photos.
The only reason to scan clientside for a cloud service is to scan files that are not uploaded, or are end to end encrypted.
Apple already maintains an e2e backdoor (in the form of non e2e iCloud Backup) for the FBI and US intelligence agencies. It is extremely unlikely that they will e2e encrypt iCloud Photos.
I suppose had they not gone down this road, the headlines would have been "Apple makes it easier to share child porn online".
I doubt they'd bother doing e2e for iCloud Photos if they're intentionally not doing it for iCloud Backup.
Citation? I don't believe this is correct, or at least it's an incomplete assertion.
Assuming they do get with the iCloud backup, these keys would be inside the device's Keychain file which is encrypted at rest by the Secure Enclave. Thus even with access to a full, unencrypted backup of your iPhone, the keychain itself cannot be decrypted by Apple
(It can't be decrypted by you either, if it's restored to different hardware. This is why iCloud Keychain exists. And that is end-to-end encrypted.)