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Volume 2017 (2017), Article ID 1490283, 14 pages
Research Article

Efficient Privacy-Preserving Protocol for k-NN Search over Encrypted Data in Location-Based Service

1School of Cyber Security, Shanghai Jiao Tong University, Shanghai 200240, China
2Department of Computer Science and Engineering, Shanghai Jiao Tong University, Shanghai, China

Correspondence should be addressed to Weidong Qiu

Received 1 September 2017; Revised 13 November 2017; Accepted 20 November 2017; Published 20 December 2017

Academic Editor: Jia Wu

Copyright © 2017 Huijuan Lian et al. 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.


With the development of mobile communication technology, location-based services (LBS) are booming prosperously. Meanwhile privacy protection has become the main obstacle for the further development of LBS. The -nearest neighbor (-NN) search is one of the most common types of LBS. In this paper, we propose an efficient private circular query protocol (EPCQP) with high accuracy rate and low computation and communication cost. We adopt the Moore curve to convert two-dimensional spatial data into one-dimensional sequence and encrypt the points of interest (POIs) information with the Brakerski-Gentry-Vaikuntanathan homomorphic encryption scheme for privacy-preserving. The proposed scheme performs the secret circular shift of the encrypted POIs information to hide the location of the user without a trusted third party. To reduce the computation and communication cost, we dynamically divide the table of the POIs information according to the value of . Experiments show that the proposed scheme provides high accuracy query results while maintaining low computation and communication cost.