Thinking out loud some more: usernames are a terrible idea. Maybe using a hash, (like Tox does) is a way to individualize recipients, and meta data: phone, ema

Thinking out loud some more: usernames are a terrible idea. Maybe using a hash, (like Tox does) is a way to individualize recipients, and meta data: phone, email, etc are then tied to that (eg like keybase does it). This way friends lists can be harvested from the phone (something I'm always wary of) for the masses, whereas privacy conscious ppl can maintain it by giving out a throwaway email address. It means you could set up Signal on multiple phones and not once leak your phone number by using the same hash account. It probably wouldn't even need a password (again, like Tox).