//! Key stretching function trait.
use cratePakeError;
use Vec;
use Zeroizing;
/// A key stretching function (KSF) used to harden passwords.
/// Identity key stretching function (pass-through).
///
/// **WARNING: Not suitable for production.** This KSF applies no work factor
/// and returns the input unchanged. It exists solely for RFC test vectors
/// that specify no password hardening. In production, use a proper KSF such
/// as Argon2id (see `pakery-crypto::Argon2idKsf`).
;