SEMA: Secure and Efficient Message Authentication Protocol for VANETs.

Message authentication and conditional privacy preservation are two critical security issues in vehicular ad hoc networks (VANETs), which have been extensively studied in recent years. To achieve these security issues, many information security technologies have been proposed so far. Among them, pseudonyms-based and group-based messages signing and verifying are two of the main methods adopted in recently published literature. However, analysis points out that both of the two technologies have their downsides. To address these issues, a secure and efficient message authentication protocol (SEMA) is proposed in this article, which aims to achieve mutual authentication among vehicles and road-side units (RSUs) in VANETs by combining the advantages of pseudonyms-based and group-based methods. Security analysis shows that SEMA is robust to various security attacks. Performance evaluation demonstrates that SEMA is computationally lightweight on both vehicles and RSUs. Finally, simulations are performed to prove the feasibility in highway and urban environment. [ABSTRACT FROM AUTHOR]