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International Journal of Vehicular Technology
Volume 2009 (2009), Article ID 702346, 14 pages
Research Article

Noninteractive, Anonymously Authenticated, and Traceable Message Transmission for VANETs

Department of Electronics, Communications and Computers, Faculty of Engineering, Helwan University, 1 Sherif Street, 11792 Helwan, Cairo, Egypt

Received 15 July 2009; Accepted 24 November 2009

Academic Editor: Kui Wu

Copyright © 2009 Maged Hamada Ibrahim. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Unlike sensor and other ad-hoc wireless networks, vehicular ad-hoc networks (VANETs) are characterized by its high mobility which allows a very short communication interval among onboard units (OBUs) and between an OBU and road-side units (RSUs). This major characterization motivates the design of communication protocols that are noninteractive or at least require a very limited number of rounds between units. The challenging issue is that such protocols must satisfy a number of security services that could be complex by their nature. In secure VANETs protocols, anonymity and traceability are two important services, yet, achieving a satisfactory security level for both of them—with acceptable complexity—is not an easy task due to the contradicting requirements: anonymous transmission must not be traceable by any individual while if a transmission is traceable, then anonymity is threatened. Existing secure VANETs protocols for anonymous and traceable transmissions either, provide unconditional anonymity where traceability and revocation are impossible, or grant trust to a thirdparty not to reveal the identity of a unit unless there is a legal reason. In this paper, we propose the first secure VANET protocol that allows authenticated transmission among OBUs and RSUs and at the same time enjoys the following properties. (i) The transmission among OBUs and RSUs is noninteractive (i.e., a one-move transmission without any interactive setup requirements). (ii) The authenticated transmission between any pair of units is anonymous (i.e., no single authority knows any information about the identity of the communicating OBU). (iii) In serious road crimes (e.g., hit-and-run, road rage, etc.) and under court order, an OBU could be traced to its clear identity. We also show how our protocol could be used to setup a confidential session between any pair of units without relying on extensive number of interactive rounds.