Matt Blaze on Nostr: A related question is the legality. It's, well, complicated, at least under US law. ...

A related question is the legality. It's, well, complicated, at least under US law. See our eponymous paper on how complicated. https://jolt.law.harvard.edu/assets/articlePDFs/v30/30HarvJLTech1.pdf (Our focus here was on government interception, but similar laws apply against private wiretapping).