A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks (VANETs) <s> Challenge on Group Signature <s> Communication messages in vehicular ad hoc networks (VANET) can be used to locate and track vehicles. While tracking can be beneficial for vehicle navigation, it can also lead to threats on location privacy of vehicle user. In this paper, we address the problem of mitigating unauthorized tracking of vehicles based on their broadcast communications, to enhance the user location privacy in VANET. Compared to other mobile networks, VANET exhibits unique characteristics in terms of vehicular mobility constraints, application requirements such as a safety message broadcast period, and vehicular network connectivity. Based on the observed characteristics, we propose a scheme called AMOEBA, that provides location privacy by utilizing the group navigation of vehicles. By simulating vehicular mobility in freeways and streets, the performance of the proposed scheme is evaluated under VANET application constraints and two passive adversary models. We make use of vehicular groups for anonymous access to location based service applications in VANET, for user privacy protection. The robustness of the user privacy provided is considered under various attacks. <s> BIB001 </s> A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks (VANETs) <s> Challenge on Group Signature <s> In ad hoc wireless networks like Vehicular ad hoc Network (VANETs) or Wireless Sensor Networks (WSN), data confidentiality is usually a minor requirement contrary to data authenticity and integrity. Messages broadcasted from a node to other nodes should be authentic but also keep user's privacy in plenty scenarios working with personal data. Group signatures (GS) are used to provide privacy and authenticity to the users. Moreover, GS with batch verification can be efficient. Nevertheless, the current solutions have practical drawbacks like using an expensive tamper-proof hardware, the computation bottlenecks of the verification and revocation phases, complicated certificate distribution/revocation or omitting important properties like short-term linkability which is demanded in several applications, e.g. change lanes of vehicles in VANETs. To our best knowledge, our solution employs the short group signature with short-term linkability and categorized batch verification for the first time. Our solution provides more efficient signing and verification than compared schemes. Moreover, the solution allows secure and practical registration and revocation of users. The usage of proposed scheme protects the honest users who can now join and securely communicate without losing their privacy. <s> BIB002 </s> A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks (VANETs) <s> Challenge on Group Signature <s> Advances in mobile networking and information processing technologies have triggered vehicular ad hoc networks (VANETs) for traffic safety and value-added applications. Most efforts have been made to address the security concerns while little work has been done to investigate security and privacy for value-added applications in VANETs. To fill this gap, we propose a secure and privacy-preserving scheme for value-added applications in VANETs; specifically, a vehicular secure and privacy-preserving location-based service (LBS). For each LBS transaction, the scheme provides authentication, integrity and non-repudiation for both the service provider and the vehicle. A vehicle can obtain the service in an anonymous way and hence vehicle privacy is well protected. However, if a vehicle maliciously uses the service, a tracing procedure can be invoked to find the malicious vehicle, thereby efficiently preventing vehicles from abusing the anonymity provided by the system. These features are achieved by efficiently exploiting the available infrastructure of VANETs and without requiring cooperation from other vehicles, which might be reluctant to cooperate or otherwise unavailable. Although public-key cryptosystems are employed as building blocks, no complicated certificate management is required by our system. <s> BIB003
In VANETs, the group signature is a robust authentication technique, which is used to provide secured communication in a vehicular network. However, the key distribution group of a high-speed moving vehicle still remains a challenging issue. In Reference BIB002 , Malina et al. introduced a group signature with short-term linkability and categorized the batch verification. This scheme produced an efficient signing mechanism and provided a secure mechanism to register and revoke users. However, this mechanism required a longer time to solve the batch verification when a large number of malicious messages was presented in the batch. In Reference BIB001 , Sampigethaya et al. introduced a scheme they call AMOEBA to provide location privacy by using a group of vehicles. This scheme enables all members of the group to send a message anonymously to the group manager. This method protects user privacy by ignoring the group manager. However, AMOEBA has a main concern in which the information such as location, id, etc. can be disclosed by the group leader. Zhang et al. BIB003 introduced an LBS protocol, in which the proposed method is able to provide different security services to the vehicle user and service provider for each transaction. This method ensures vehicle privacy by providing service to the vehicle anonymously. However, in case of heavy vehicle density, each LBS event may introduce large computational overhead. From the above schemes, we analyze that the researcher from the wireless communication technology background should focus on the VANET security services and scalability of key distribution schemes in group-based signature authentication.