[sircastor]

> They produce mountains of unactionable reports, false positives, and their (or was it Microsoft’s) weird hashing thing was visually identifiable as CSAM itself and reversible.

Are there examples or reports of this? I hadn’t heard this before. (It’s not hard to believe though, eg TSA airport security)

[stephen_g]

This paper [1] cites some stats from the UK over one year (I think 2019) - from about 29.4m reports to NCMEC, 102,842 were referred to the NCA, of which 20,038 were referred to policing agencies, which led to 6,500 suspects, and about 750 of those suspects were prosecuted, which it estimates makes up about 3% of all prosecutions for indecent image offences. That comes out to about 0.7% of NCMEC reports to the UK's NCA leading to prosecution.

I read another article that linked to stats from Irish and Swiss federal police, and both of them reported discarding about 80% of NCMEC's reports to them in the first stage as not being at all criminally relevant, but I can't find the link right now.

1. https://www.cl.cam.ac.uk/~rja14/Papers/chatcontrol.pdf

[Someone]

> That comes out to about 0.7% of NCMEC reports to the UK's NCA leading to prosecution

That doesn’t imply the rest was unactionable. Certainly, the reductions from 20,038 to 6,500 and from there to 750 aren’t due to this tech. The first could be because it produced multiple hits for one person, the second because of policies of the police (minors might have been warned rather than prosecuted, untraceable phone numbers ignored, and persons known to have died removed, for example)

NCMEC also would (rightfully, AFAIK) argue that they never claimed the code to be perfect, and that the earlier reductions are by design.

The real problems, IMO, are (from that pdf):

“the data do not support claims of large-scale growing harm that is initiated online and that is preventable by image scanning.”

and

“The first wave of prosecutions for illegal abuse images, Operation Ore, swept up many innocent men who were simply victims of credit card fraud, their cards having been used to pay for illegal material. A number were wrongly convicted, and at least one innocent man killed himself”

[projektfu]

Wow, that's a Kafkaesque nightmare.

[krinchan]

Back when the news first came out there were several blog posts posted to HN by people who host user uploaded photos at scale who had NCMEC come knocking at their door to strong arm them into participating in their programs.

They are not even a proper government agency yet they walk around with the balls to pretend they are equivalent to the NSA.

[sroussey]

It’s even worse than you can imagine. Even when you find an image… you can’t delete it right away, so as to not tip your hat that it was automated.