unsolved problems for fully decentralized P2P instant messaging

1. How do you assign persistent usernames to potentially rapidly changing IPs? You can't use a centralized server or any side channels (like an email address).

2. How do you do push notifications in Android or iOS? Push notifications are sent by Apple or Google servers via your signed, trusted (centralized) server(s).

Tox (the chat protocol) solves #1 by using centralized servers and #2 by simply not doing push notifications (which is unacceptable).

I dream of a chat client that has all the features of Messenger or iMessage without having to trust anyone. No central server in the middle. Just my message to your device and back and forth.

>>3
As far as I can tell, everything still goes through Signal's servers. The main difference between it and Messenger/WhatsApp/iMessage is that it's open source and uses a lot of cryptography. Anyway WhatsApp and iMessage both already do end-to-end encryption, so I don't see what Signal brings to the table aside from being open source.

Also Signal requires you to verify with a real phone number. Let's say you're a dissident in a dictatorship. The government checks if you got the verification SMS from Signal--boom, you're dead.

The point is not just end-to-end encryption. It's about not having to rely on Facebook or Apple to do something as ordinary as messaging. It's the holy grail of privacy AND software independence/freedumbs.