Well you got the answer to your question I think! A huge amount of technical ignorance and fear on display here, as in all the other discussions on this. The ‘outraged’ seem to fall into one of these categories:
“Apple has no right to look at photos on my device! If they start ‘scanning’ my private photos, who knows where it will end?”
My reply: Apple has been using on-device AI (e.g. face recognition) to analyse the content of your photos for years. If you don’t trust them now, why did you before? (FYI, hashing an image doesn’t involve AI at all. Correction: Apple's NeuralHash system does use AI to recognise matching images that might have undergone minor changes, like being 'slightly cropped or resized'.)
“This is a huge violation of my privacy! Apple has betrayed us all after telling us they take privacy seriously!”
My reply: Only if you store child pornography. For everyone else, nothing private gets shared at all. Your photos don’t even get analysed by Apple—they just get a meaningless string of characters to compare with those in the database, and anything short of an exact match is ignored. Even if they wanted to convert those hashes back to the original images, they can’t. That’s the whole point of a cryptographic hash.
“This opens a back door for the bad guys to get all sorts of information from my device!”
My reply: No it doesn’t. It only allows matching of images against a database of known CSAM images. The final step in the process is human review by Apple to guard against the extremely unlikely event of a false positive.
”Oppressive regimes could potentially use this to find and abuse dissidents.” This is about the only valid concern I’ve heard, but it would require them to (1) find a way to add other non-CSAM images to the database, and (2) convince Apple to hand over the matching records. Apple has responded by making clear the process of maintaining the database, and categorically stating that they will refuse all such requests. Based on their solid record in the past (and the absolute PR disaster that such a failure would be) I see no reason to suspect that they would lie about this.
So basically, we are forced to place some trust in the people at Apple, but that has always been the case. For the record, I certainly don’t agree with everything Apple does, but personally, I don’t understand all the anger over this one, and the personal attacks on Apple leadership. Remember, these are people like you and me, with families, and social consciences. Before you join the lynch mob over your false sense of privacy violation, why don’t you pause to consider the violations of human rights that could be avoided if all tech companies took their responsibilities to society seriously.