Password-based Key Derivation Function (PBKDF)
A password-based key derivation function (KDF) is used to take a user's password and transform it into a key suitable for applications like encryption.
A popular PBKDF is aptly-names PBKDF2. It was defined by RSA as a component of PKCS#5 v2.0 (published also in RFC 2898) and is recommended as an acceptable algorithm for such application by NIST in NIST SP 800-132. PBKDF2 relies on a Pseudorandom Function (PRF) and is often used in practice with HMAC serving as that PRF.