I've long held a grudge against Microsoft and NCMEC for not providing this technology, because I live in a country where reporting CSAM is ill-advised if you're not a commercial entity and law enforcement seizes first and asks questions later (_months_ later), so you end up just closing down a service if it turns out to be a problem.

This puts it into perspective. PhotoDNA seems fundamentally broken as a hashing technology, but it works just well enough with a huge NDA to keep people from looking too closely at it.

NCMEC needs a new technology partner. It's a shame they picked Apple, who are likely not going to open up this tech.

Without it, it's only a matter of time until small indie web services (think of the Fediverse) just can't exist in a lot of places anymore.