[AdamJacobMuller]

Not necessarily. There are much newer technologies than simple hashes of files now, which are effectively content-aware image hashing algorithms which are highly resistant to manipulation techniques (re-encoding, resizing, even things like rotation/blur) they are of course tunable algorithms which the more you want to catch the more false positive rate there is but you can already today do much better than simple file hash.

Look at https://www.microsoft.com/en-us/photodna and https://openbase.com/python/ImageHash/documentation

[SpaghettiCthulu]

People have found ways to bypass and reverse (albeit with reduced quality) Photodna

Edit: here's a source https://www.anishathalye.com/2021/12/20/inverting-photodna/

[_manifold]

I think it's definitely more useful, especially long term, in a more controlled system where the government agency that is handling the actual CSAM is simply submitting hashes of the content the company (Microsoft, Apple, or whoever else) to add to their database with which they can use to flag/review suspicious content.

However, the system described in the article is open to the public, and simultaneously privacy/anonymity oriented. I see this as a double-edged sword. While it does protect the identity of legitimate users, that also opens it up to nefarious actors flooding the system with images/videos taken from legitimate content creators on OnlyFans other sites, potentially getting those creators' content flagged/removed. Even if this simply triggers a manual review, you could feasibly spam the system with so many that it grinds to a halt.

[zamnos]

Good thing it's open source, now I know how much I need to change the image in order for the hash to change!