a simple mechanism is using a smart contract to map your key (0x123) to an identity (@alice). the contract can allow you to transfer that identity to a different key (important for key rotation) and also to set up a recovery key that is also authorized to transfer the key if the primary key is lost.
our recovery system for Farcaster has a few more bells and whistles, and you can read about it here: https://github.com/farcasterxyz/protocol#33-recovery