SECURITY AND COMMUNICATION NETWORKS Security Comm. Networks 2011; 4:771–784 Published online 8 February 2011 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/sec.266 SPECIAL ISSUE PAPER RAMV: ensuring resource-aware message verification in VANETs Zhengming Li *,† and Chunxiao Chigan ‡ Department of ECE, Michigan Technological University, MI, U.S.A. ABSTRACT Driven by road safety applications and commercial applications, verification of messages’ content integrity and authenticity in vehicular ad hoc networks (VANETs) is indispensable. However, due to numerous message exchanges in VANETs, message verification often leads to excessive resource consumption and even resource depletion in vehicular nodes. To tackle the scalability issue, a novel resource-aware message verification (RAMV) scheme is proposed in this paper. With application specific differentiation of the messages to better support road safety applications, RAMV streamlines the existing message verification schemes to keep their resource consumption within the preset resource budget. Meanwhile, the common security requirements for message verification are all properly met by RAMV. Enabling resource-aware, safety-upholding, and secure message verification, RAMV is especially appealing to the forthcoming massive deployment of VANETs. Copyright © 2011 John Wiley & Sons, Ltd. KEYWORDS VANET; message verification; resource consumption * Correspondence Chunxiao Chigan, Department of ECE, Michigan Technological University, MI, U.S.A. E-mail: cchigan@mtu.edu † Zhengming Li is a PhD candidate with ECE Department of Michigan Technological University. His research interest is mainly focused on security provisioning and privacy protection in VANETs. ‡ Chunxiao Chigan is currently an associate professor with ECE Department of Michigan Technological University. Her research interest includes message dissemination and security provisioning in VANETs, as well as cognitive radio networking and its security. 1. INTRODUCTION Nowadays Vehicular Ad Hoc Networks (VANETs) open the door to numerous promising applications for road safety, driving convenience and commercial activities. On the other hand, the application significance of VANETs imposes severe security challenges[1], including privacy, message authenticity, message integrity, node non-repudiation, etc. Among them, message authenticity requires that each mes- sage contains valid content, which is critical to various VANET (especially road safety) applications. Message integrity requires that each message can be proved to be gen- erated by the claimed source, which is useful for the liability scenarios. Thus, content verification and source verification, two forms of message verification, are critical to VANETs to ensure message authenticity and message integrity, respec- tively. Regardless of the implementation details, message verification, especially source verification which relies on digital signature verification, is surely resource demanding. In VANETs, message verification threatens varying and excessive resource consumption in face of the massive mes- sage exchanges. Such massive message exchanges result from the periodic messages broadcasted by each node to support road safety applications (Beacons) and other applications (neighbor information for proactive routing[2], information abstract in epidemic routing[3], or simplistic message flooding[4]). Each node thus needs to receive and verify numerous messages per second, the exact number of which changes linearly with the node density in the neighborhood. The resource consumed by message veri- fication, given any algorithms adopted, tends to be huge and will make message verification non-scalable. Moreover, the variances in resource consumption will also negatively affect the resource available to other VANET applications. Thus, it is desirable to make message verification in each node resource-aware, in that its resource consumption in any circumstances will be bounded by the actual resource available to message verification, in form of resource bud- get. For brevity, this paper only explicitly considers the verification of Beacons, which, periodically broadcasted by each node to signal the driving status, may be the most prevalent messages in VANETs. Copyright © 2011 John Wiley & Sons, Ltd. 771