Multikeyword-Ranked Search Scheme Supporting Extreme Environments for Internet of Vehicles

In recent years, the cloud infrastructure has been developed as a promising sharing system for the Internet of Vehicles (IoV) communication. During the information exchange, search service over ciphertext called searchable encryption (SE) is an extraordinary method to prevent data breaches. However, two open problems still need to be solved for ranked search, which hinders the application practicality in IoV. First, each data owner must store the extra information to distribute weight values dynamically. Second, ranking in the cloud has not been supported by most existing schemes. In this article, to address the above problems and fit the characteristics of real-time data exchange in IoV, we present a multikeyword-ranked search scheme supporting extreme environments for the IoV. Specifically, our system designs a unique encrypted index tree structure to realize the multikeyword-ranked retrieval, the weight value dynamic adaptive calculation, and dynamic updating in IoV. Moreover, we use a primary–secondary dual-server model to cope with extreme environments and propose a “greedy breadth-first search” algorithm to achieve an effective sublinear search. Finally, comprehensive security analysis and experimental simulation for the proposed system prove that our system can guarantee user privacy and acceptable efficiency.

I. Introduction

Cloud computing [1] is gradually becoming an essential infrastructure for the Internet of Vehicles (IoV) [2] communication due to its flexible access control, which is not limited by region or time and provides on-demand computing resources at a minimum economic cost. Simultaneously, data sharing based on the cloud has become an indispensable method for IoV to realize the efficient interconnection between people, vehicles, and things. In particular, the growing number of self-driving trips leads to increasing requirements for cloud-based information retrieval services (e.g., navigation, entertainment, and charging). The fusion of IoV and the cloud provides much convenience for personal travel. For example, the self-driving service provided by intelligent cloud navigation achieves optimal route planning and significantly improves traffic efficiency. However, the cloud is controlled by an incomplete trusted third party, which leads to a potential risk of privacy leakage during data interaction. Therefore, data needs to be encrypted before uploading to the cloud. Nevertheless, querying encrypted data in the cloud is a nontrivial task, as the entire data set needs to be downloaded locally and then decrypted and queried quickly. Fortunately, searchable encryption (SE) [3] provides a practical solution to realize remote queries of encrypted data efficiently.