Secure Session Key Generation. Creating PRF from MAC Function
This document describes Pseudo Random Function (PRF) based on MAC function (keyed iterated hash function), and offers a ref- erence implementation of PRF based on SHA-1. This PRF can be used to produce cryptographic keys for authen- tication/integrity and encryption. It uses pre-shared secret and publicly known random value (and possibly parties’ identi- ties). The main advantage of this algorithm over other similar ones is that its security is formally tied to the MAC property of the underlying function.