MAAC: Message Authentication Acceleration Protocol for Vehicular Ad Hoc Networks

Vehicular ad hoc networks (VANETs) adopt the public key infrastructure (PKI) and certificate revocation lists (CRLs) to reliably secure the network. In any PKI system, the authentication of a received message is performed by checking that the certificate of the sender is not included in the current CRL, and verifying the authenticity of the certificate and signature of the sender. In this paper, we propose a message authentication acceleration (MAAC) protocol for VANETs, which replaces the time-consuming CRL checking process by an efficient revocation check process. The revocation check process uses a keyed hash message authentication code (HMAC), where the key used in calculating the HMAC is shared only between non-revoked on-board units (OBUs). In addition, the MAAC protocol uses a novel probabilistic key distribution, which enables non-revoked OBUs to securely share and update a secret key. By conducting security analysis and performance evaluation, the MAAC protocol is demonstrated to be secure and efficient.