Just public key cryptography. All your actual posts and comment history are already shared. What is missing is a way to authenticate yourself to anyone but your home server. If the protocol included every profile having a public key, you could then use that to authenticate to any server. And managing that private key is no more complicated than managing your private key in a block chain context.
Non public info like subscriptions is a bit more complicated, because there is an actual policy question of who you share it with. You would either need to make it publicly available, keep a copy yourself, or have your home instance give it to you/the other server at the time you want to migrate.
Just public key cryptography. All your actual posts and comment history are already shared. What is missing is a way to authenticate yourself to anyone but your home server. If the protocol included every profile having a public key, you could then use that to authenticate to any server. And managing that private key is no more complicated than managing your private key in a block chain context.
Non public info like subscriptions is a bit more complicated, because there is an actual policy question of who you share it with. You would either need to make it publicly available, keep a copy yourself, or have your home instance give it to you/the other server at the time you want to migrate.