fcb ₿ on Nostr: It's built into the protocol, and frankly, a somewhat inherit part of how most social ...

It's built into the protocol, and frankly, a somewhat inherit part of how most social networks work. You have to know an address for the sender for it to get there, if that is encrypted, than no one will know where their message is (unless every client is attempting to decrypt metadata for *every* message ever sent).

However, Signal has taken some exotic steps to reduce their ability to see those messages, namely leveraging enclave tech like SGX: https://signal.org/blog/building-faster-oram/

There are ways to obfuscate the identity of the sender/receiver, but that metadata still must be present unencrypted to allows messaging protocols to work. Maybe there's some crazy way to do it with quantum tech, but we're still a ways from that :D