Privacy-preserving authentication based on group signature for VANETs

In this paper, we present an efficient privacy-preserving authentication scheme based on group signature for Vehicular Ad Hoc Networks (VANETs). Although group signature is widely used in VANETs to realize anonymous authentication, the existing schemes based on group signature suffer from long computation delay in the Certificate Revocation List (CRL) checking and signature verification process, leading to high message loss. As a result, they cannot meet the requirement of verifying hundreds of messages per second in VANETs. In our scheme, we first divide the precinct into several domains, in which road side units (RSUs) are responsible for distributing group private keys and managing vehicles in a localized manner. Then we use Hash Message Authentication Code (HMAC) to avoid the time-consuming CRL checking, and to ensure the integrity of messages before batch group authentication. At last, we adopt cooperative message authentication among entities, in which each vehicle just needs to verify a small number of messages, thus greatly alleviating the authentication burden. The security and performance analysis show that our scheme is more efficient in terms of authentication speed, while keeping conditional privacy in VANETs.