For those that want to use a (user-controlled) public-key as a basis of an ID on the Fedivese to help enable account and data portability —
Using public-keys could work.
But, there are some issue to address:
№1:
how do we enable key rotation,
№2:
how do we enable users to have multiple keys (maybe for different devices), and
№3:
how do we enable users to be able to revoke keys.