Agree. I'm not a cryptographer and never claimed to be either. -- and I think it would be difficult to mistake me for a hipster. For one, I don't have that snazzy majestic beard.. Anyway, on to the point. :)
Yes, the phone number thing is a policy decision by the Signal people. As I write in my article, it's maybe marginally easier to get connected using phone numbers, but I may want to communicate via Signal with someone I don't want to give my phone number to. Handing out personal phone numbers on the willy nilly is not something I'm comfortable with. There's no reason why we couldn't have some other identifier, possibly easy to remember to connect us to via Signal. So this was a policy decision by the Signal people.
Federation is indeed hard to get right, but I think with proper versioning, and various teams keeping their software up-to-date and close to the reference paper/the Signal protocol, I see no reason why it cannot be overcome. For XMPP/Jabber it also works quite well.
Yes, the phone number thing is a policy decision by the Signal people. As I write in my article, it's maybe marginally easier to get connected using phone numbers, but I may want to communicate via Signal with someone I don't want to give my phone number to. Handing out personal phone numbers on the willy nilly is not something I'm comfortable with. There's no reason why we couldn't have some other identifier, possibly easy to remember to connect us to via Signal. So this was a policy decision by the Signal people.
Federation is indeed hard to get right, but I think with proper versioning, and various teams keeping their software up-to-date and close to the reference paper/the Signal protocol, I see no reason why it cannot be overcome. For XMPP/Jabber it also works quite well.