nostr (https://github.com/fiatjaf/nostr https://github.com/fiatjaf/nostr) seems to be a minimal possible solution. It doesn't seem to be much in use though, so

nostr (https://github.com/fiatjaf/nostr https://github.com/fiatjaf/nostr) seems to be a minimal possible solution. It doesn't seem to be much in use though, so I guess once that happens a few issues will come up.