Technology

So the standard approach to this is so-called "perceptual hashing." Effectively, using cryptographic hashes (sha256, etc.) doesn't really work well in this case. Given a piece of illegal content, that content is likely to still be just as illegal with a single pixel changed -- however, it'll have a completely different cryptographic hash. So instead, a hash function that determines how "similar-looking" two images are, ignoring things like dimensions, color palette, JPEG compression artifacts, etc. This is obviously way fuzzier, and is prone to both false positives and negatives.

Because all this is inherently kinda fuzzy, the exact database of hashes is usually "secret sauce" if you will. If it were public, it would be super easy to circumvent. As an example, given an illegal image:

1. Is the image's hash in the DB?
2. No? All done, you can post it with impunity.
3. Yes? Change one random pixel, GOTO 1.

As a result even "public" databases are distributed with NDAs etc. This obviously does not jive well with an open source, federated network like Mastodon, and I have my doubts as to how willing the relevant agencies would be to give their databases to every rando with $5 to spin up a Pleroma instance on a VPS. A public DB might help in some cases, but unfortunately more illegal content is produced every day, and so it would be extremely hard to keep up with the bad actors.

This is kind of problematic... By creating a community driven hashlist that is freely shared, you've also kind of created an index of CSAM content that could easily be extrapolated for people actively looking to find/share that content.

I'm not suggesting Beehaw/etc should be government funded. Rather I'm suggesting it's already possible for basically anyone in the fediverse to report a post as needing urgent moderator attention.

I think there will be tax payer funded efforts, donation funded efforts, volunteers, etc that are unaffiliated with any specific instance but go through major instances and hit the report button where they consider it to be appropriate — not just manually with people but also with automated tools such as searching for images by a hash of their contents or maybe even running messages through a Large Language Model to check if it is, for example, a form of targeted harassment.

And yes, the report feature will be abused. That's unavoidable and needs to be taken into account when deciding how to respond to a report. An algorithm could easily prioritise reports based on the history of past reports made by the same person / organisation.

Stack Exchange has a pretty good system - decisions by individuals are not trusted. Rather those trigger a review by a randomly selected (and trusted) individual to get a second opinion. And even after a decision has been made and an action has been taken (ban a user, etc) there's often a third or even fourth review. And there are processes to appeal and question decisions.

It's not an easy problem to solve, but as the creator of mastodon said - many hands make light work. The fediverse can some day have a billion people doing moderation tasks - where even simple acts like hitting the upvote button become part of the moderation system (upvote would imply that this account holder tends to make valuable contributions to the community, and should make the moderation system less likely to come down with a ban hammer).

And I also think there is scope for some communities to be entirely government funded. For example I'd love for every city in the world to run an offical community, with official local government anouncements as well as moderated discussions relevant to people who live in or are visiting the city.