Research Article NTRU Implementation of Efficient Privacy-Preserving Location-Based Querying in VANET Bo Mi, 1 Darong Huang, 1 and Shaohua Wan 2 1 Institute of Information Science and Engineering, Chongqing Jiaotong University, Chongqing 400074, China 2 School of Information and Safety Engineering, Zhongnan University of Economics and Law, Wuhan 430073, China Correspondence should be addressed to Shaohua Wan; shaohua.wan@ieee.org Received 26 January 2018; Accepted 21 March 2018; Published 3 May 2018 Academic Editor: Xuyun Zhang Copyright © 2018 Bo Mi et al. Tis 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. Te key for location-based service popularization in vehicular environment is security and efciency. However, due to the constrained resources in vehicle-mounted system and the distributed structure of fog computation, disposing of the conficts between real-time implementation and user’s privacy remains an open problem. Aiming at synchronously preserving the position information for users as well as the data proprietorship of service provider, an efcient location-based querying scheme is proposed in this paper. We argue that a recent scheme proposed by Jannati and Bahrak is time-consuming and vulnerable against active adaptive corruptions. Tus accordingly, a postquantum secure oblivious transfer protocol is devised based on efcient NTRU cryptosystem, which then serves as the understructure of a complete location-based querying scheme in ad hoc manner. Te security of our scheme is proved under universal composability frame, while performance analysis is also carried out to testify its efciency. 1. Introduction With the development and fusion of techniques such as sensing, controlling, communication, positioning, and fog computation, vehicular ad hoc network (VANET), which is identifed as a specifc application of Internet of Tings (IoT), has become a promising understructure to enhance trafc safety and convenience. As an important element of the intelligent transportation system (ITS), VANET is typically composed of numerous on-board units (OBU) equipped on vehicles and road-side units (RSUs) serve as infrastructure [1]. Diferent from traditional networking, vehicular ad hoc network emphasizes heavily on adaptive computation as well as communication of end-users and edge devices, which is characterised as localized data storage, dense geographical distribution, boundary service providing, and compound data aggregation or analysis. A wide range of applications can be supported taking advantage of such fundamental installation; for example, when driving on the road, one can fall back on the VANET to locate services (shops, gas stations, etc.) on his route, or even be notifed of any forecasted trafc condition along her itinerary. Tough it is envisioned that the future transportation would be “information-driven” and “wirelessly enabled,” the prob- lems of confdential and privacy-preserving communica- tion remain insufciently solved due to the broadcasting nature of VANET [2]. Moreover, since one of the most attractive applications of VANET is location-based querying, it is always self-extended to traditional networks such as Internet. As illustrated in Figure 1, any authorized on-board unit may access the querying service providers (QSPs) in backbone or local RSUs to inquire about interested infor- mation via various communication channels, which makes the security issue more complicated in such foggy environ- ment. As for privacy, the user may not want anybody, including the infrastructure units or service providers, to be aware of any information about her query. Tat means it should either be impossible to link up a query with the real identity of the user or make the query itself indistinct to some extent. In order to accomplish privacy requirement, two research lines are followed in literatures. Hindawi Wireless Communications and Mobile Computing Volume 2018, Article ID 7823979, 11 pages https://doi.org/10.1155/2018/7823979