As I understand it (and I've not spent too long on this, just picking at various articles) - there are two separate things at play here.
Firstly - CASM scanning is done via fingerprinting - the image is fingerprinted on device and when uploaded to iCloud that fingerprint is compared with the "dodgy images" fingerprints and an alert raised if a threshold of matches is reached (what's the threshold and with whom?)
Secondly - there is on-device AI image recognition - when you send an image to someone else (via iMessage or the share sheet) it is checked for nudity and if the iCloud account in question is registered to a 13-year old or younger, their parents are alerted.
In both cases the fingerprinting/scanning is on-device and is triggered by the images leaving the device.
> the image is fingerprinted on device and when uploaded to iCloud that fingerprint is compared with the "dodgy images" fingerprints and an alert raised if a threshold of matches is reached (what's the threshold and with whom?)
Nope. The comparison is done on the device and the threshold is set there as well.
I am not sure how alarmed I am yet at this whole affair but I do know that maybe 50% of posts I read about this have glaringly incorrect information which definitely dampers my alarmism.
> Nope. The comparison is done on the device and the threshold is set there as well.
As I understand it the fingerprinting and comparison is done on device, but it only happens as part of the upload-to-iCloud process. So the grandparent's phrasing isn't unreasonable.
Firstly - CASM scanning is done via fingerprinting - the image is fingerprinted on device and when uploaded to iCloud that fingerprint is compared with the "dodgy images" fingerprints and an alert raised if a threshold of matches is reached (what's the threshold and with whom?)
Secondly - there is on-device AI image recognition - when you send an image to someone else (via iMessage or the share sheet) it is checked for nudity and if the iCloud account in question is registered to a 13-year old or younger, their parents are alerted.
In both cases the fingerprinting/scanning is on-device and is triggered by the images leaving the device.