Password-based Key Derivation Function

cryptography security

Definition

Password-based Key Derivation Function

A password-based key derivation function (PBKDF) is a key derivation function that derives one or more secret keys from a user-provided password or passphrase.

It applies a cryptographic hash function or pseudorandom function repeatedly with a salt and an iteration count, making brute-force attacks proportionally more expensive.

Instances

PBKDF2

Iterated HMAC with XOR accumulation. Defined in RFC 2898 / PKCS #5.

Bcrypt

Based on the Blowfish cipher. Adapts its cost factor over time.

Scrypt

Memory-hard: increases memory requirements in addition to CPU time.

Argon2

Winner of the Password Hashing Competition (2015). Memory-hard with configurable time and memory costs.