[rusk]

I wonder could it be something like how diffie-helman allows a watertight tls connection to form without shared secret. In that case you could base your session on a on some random hash derived from some kind of passphrase which could be provided to later identify the session

[gruez]

AFAIK that's how tor hidden services work. Your "address" is basically a hash of your public key.

[rusk]

Yes but every time you connect to the network you have a new identity- by design - with signal you would still want a way to identify yourself across sessions