Yes, the diligent review performed by the lowest-bidding subcontractor is an excellent defense against career-ending criminal accusations. Nothing can go wrong, this is fine.

My WhatsApp automatically saves all images to my photo roll. It has to be explicitly turned off. When the default is on, it's enough that the image is received and the victim has CP on their phone. After the initial shock they delete it, but the image has already been sent to Apple, where a reviewer marked it as CP. Since the user already gave them their full address data in order to be able to use the app store, Appla can automatically send a report to the police.

Not necessarily.

If you know the method used by Apple to scale down flagged images before they are sent for review, you can make it so the scaled down version of the image shows a different, potentially misleading one instead:

https://thume.ca/projects/2012/11/14/magic-png-files/

At the end of the day:

- You can trick the user into saving an innocent looking image

- You can trick Apple NN hashing function with a purposely generated hash

- You can trick the reviewer with an explicit thumbnail

There is no limit to how devilish one can be.

The reviewer may not be looking at the original image. But rather the visual derivative created during the hashing process and sent as part of the safety voucher.

In this scenario you could create an image that looks like anything, but where it’s visual derivative is CSAM material.

Currently iCloud isn’t encrypted, so Apple could just look at the original image. But in future is iCloud becomes encrypted, then the reporting will be don’t entirely based on the visual derivative.

Although Apple could change this by include a unique crypto key for each uploaded images within their inner safety voucher, allowing them to decrypt images that match for the review process.

Depending on what algorithm apple uses to generate the "sample" that's shown to the reviewer it may be possible to generate a large image that looks innocent unless downscaled with that specific algorithm and to a specific resolution

So here's something I find interesting about this whole discussion: Everyone seems to assume the reviewers are honest actors.

It occurs to me that compromising an already-hired reviewer (either through blackmail or bribery) or even just planting your own insider on the review team might not be that difficult.

In fact, if your threat model includes nation-state adversaries, it seems crazy not to consider compromised reviewers. How hard would it really be for the CIA or NSA to get a few of their (under cover) people on the review team?

I don't see how a perfectly legal and normal explicit photograph of someone's 20-year-old wife would be indistinguishable to an Apple reviewer from CSAM, especially since some people look much younger or much older than their chronological age. So first, there would be the horrendous breach of privacy for an Apple goon to be looking at this picture in the first place, which the person in the photograph never consented to, and second, could put the couple in legal hot water for absolutely no reason.

Not one image. Ten, or maybe 50, who knows what the threshold is.