So possession of child pornography is illegal in the US even if your goal is to write code that can detect child pornography.
How does anybody solve this problem?
(Reading through the notes of today's SWICG's call on the subject https://github.com/swicg/meetings/tree/main/2023-08-04)
nostr:npub1u27r9h3j9pvrplaffsmpn698e8xhmuqhdgcxldv67ammql9pumnqha3qfq I think the short answer is "hashing". See, e.g.:
https://www.missingkids.org/ourwork/ncmecdata
https://www.thorn.org/reporting-child-sexual-abuse-content-shared-hash/
https://www.thorn.org/blog/hashing-detect-child-sex-abuse-imagery/
nostr:npub1a4tgkd6mnw6565svfaqvfsxj0auyt7gdagtterm2skxnwrtr3a9sp9q9yj and how are you supposed to test your hash algorithm?
