Bcrypt is not really a KDF, it's a strong hash generator + verification processor rolled into one for easy consumption. See PBKDF2 / RFC2898 for tooling approp

Bcrypt is not really a KDF, it's a strong hash generator + verification processor rolled into one for easy consumption. See PBKDF2 / RFC2898 for tooling appropriate to generate an expensive-to-generate cryptographic key from a user-supplied passphrase.