> but the claim is that it is set to only detect people who are actually building a collection of CSAM
From what I read the threshold is for a different purpose, ,the false positives are too many so to reduce the number of reports the threshold workaround is introduced, so is a hack to workaround the false positives and not a threshold to catch people with big collections.
I have seen both in comments from Apple. Certainly spokespeople have talked about wanting any reports to NCMEC to be actionable.
I think a lot hinges on what you call a ‘false positive’. It could mean ‘an image that is not CSAM’ or it could mean ‘an account that has some apparent CSAM, but not enough to be evidence of anything’.
I think it is clear that Apple will have no choice, if they for sure find 1 CSAM image they can't say "it is just 1 img so it is not a big collection..." they have to send it to whoever to handle it.
What would help me with this kind of things would be more transparency, like to know the algorithm, the threshold, the real numbers of false positives, can the hashes be set per country or individual, can independent people look inside iOS and confirm that the code works as described...
What would also help is to know for sure hoe many children were saved by this kind of system,
> I think it is clear that Apple will have no choice, if they for sure find 1 CSAM image they can't say "it is just 1 img so it is not a big collection..." they have to send it to whoever to handle it.
This is a misunderstanding of how it works. The threshold has to be met before a detection occurs. Unless the threshold is met Apple doesn’t get to know about any images.
As for independent auditing and transparent statistics, I fully agree.
Let's say the threshold is 10 , you trigger the threshold so Apple checks all the 10 images , but 9 are false possitive and one appears to be a correct match, Apple will report you for 1 image ... so my point is that is not designed to catch people with big collections of CP, is designed to not trigger to often.
From what I read the threshold is for a different purpose, ,the false positives are too many so to reduce the number of reports the threshold workaround is introduced, so is a hack to workaround the false positives and not a threshold to catch people with big collections.