Implementing HMAC in expedite message authentication protocol for VANET

Vehicular communications (VC) aim to enhance safety and efficiency of transportation systems. VANET adopts the Public Key Infrastructure (PKI) and Certificate Revocation Lists (CRLs) for their security. In any PKI system, every message should be digitally signed before its transmission. This paper presents a through survey of also, an Expedite Message Authentication Protocol (EMAP) for VANETs, which replaces the time-consuming CRL checking process by an efficient revocation checking process is proposed in this paper. EMAP uses a keyed Hash Message Authentication Code (HMAC). EMAP is used to enhance security and performance of message communication in VANETs and also certificate and message signature authentication acceleration.