Apple's system does seem to be robust to intentional or accidental hash collisions [1], though it is very hard to explain that to non-technical people. (Added l

Apple's system does seem to be robust to intentional or accidental hash collisions [1], though it is very hard to explain that to non-technical people. (Added later:) Because everyone seems to claim that they understand the system and do not look at the linked post, I should at least mention that the device only has "blinded" hashes that can't be used for collision attack, and the match actually occurs at the server but only when the device reports a certain amount of such hashes. But the website correctly points out a possibility of "[m]isuse by authoritarian governments" and it is what we should be definitely concerned of. It is not a CSAM detection algorithm. It is a generic image detection algorithm. [1] My own analysis: https://news.ycombinator.com/item?id=28223141 https://news.ycombinator.com/item?id=28223141