Ideally your passphrase would be secure enough that it couldn't be bruteforced from a (hashed) HN database. But in case a non-hashed database gets leaked, what

Ideally your passphrase would be secure enough that it couldn't be bruteforced from a (hashed) HN database. But in case a non-hashed database gets leaked, what sort of scheme could one use that couldn't be revealed from a single known password? I suppose one could use a system like bcrypt(passphrase + "domain.com")[:32] But anything requiring a calculation step seems to lose a lot of the advantages of a single-passphrase system.