Unfortunately the industry defined Bcrypt as a KDF for some time, even though it is better named as a "password hashing function". Cryptography has a history o

Unfortunately the industry defined Bcrypt as a KDF for some time, even though it is better named as a "password hashing function". Cryptography has a history of being bad at picking good names for new work. In addition to (true) KDFs, people often want a HKDF (HMAC-based Key Derivation Function) or hierarchical deterministic key derivation function (HDK).