Pre-broadcast based time efficient privacy protocol for secure vehicular communications

Privacy and security are two important issues in vehicular networks. Users wish to maintain location privacy and anonymity, meaning the identity, location/direction of move of their vehicles remains unknown to everybody with possible exception law enforcement authorities responsible by law to know and maintain such private information. In this paper, we propose a Pre-broadcast based Time Efficient Privacy (PTEP) scheme, which, instead of performing any asymmetric verification, uses Message Authentication Code (MAC) functionality and HASH operations to authenticate messages. Moreover, we use two-level key (upper-level hash chain and low-level hash chain) which assists avoiding message losses. Analysis shows that the proposed PTEP scheme superior performance in terms of packet loss rate and packet latency. In addition, it can be used to serve emergency and routine messages as well, while most of existing solutions can only work with routine messages.