NIP-58 is for badges, which is pretty cool. I put together a POC for Multiparty Attribute-based Encryption that could be used to send messages decipherable by accounts that meet certain badge criteria.

Such as: "((shit_poster AND influencer) OR (founder AND honor_badge) OR mega_donor))"

I don't know if it is valuable, but maybe, and the crypto works. Thoughts? I can formalize it with a better reference implementation if seems useful.
CC: @nostrich @nostrich @nostrich

https://github.com/3yekn/nostr-abe