On the security of a threshold anonymous authentication protocol for VANETs

Abstract

VANETs is a promising mobile ad hoc networks, it can significantly improve the traffic safety and efficiency. But it also raises some formidable challenges, where security assurance and privacy protection are two primary concerns. Without the security and privacy guarantees, attackers could track their interested vehicles by collecting and analyzing their traffic messages. Hence, anonymous message authentication is an essential requirement of VANETs. Recently, Shao et al. proposed a new threshold anonymous authentication protocol, and they claim that these protocol can achieve identity tracing of a malicious vehicle. Unfortunately, in this letter, we demonstrate that the protocol cannot satisfy traceability. A malicious vehicle is able to arbitrarily send the false without being traced by the group tracer in their scheme. Finally, we analyze the reason to produce and give the corresponding advise to fix this flaw.