A Grid-Based Approximate K-NN Query Processing Algorithm for Privacy Protection in Location-Based Services

Abstract

Location-Based Services (LBSs) are becoming popular due to the advances in wireless networks and positioning capabilities. Providing user’s exact location to the LBS server may lead revealing his private information to unauthorized parties (e.g., adversaries). There exist two main fields of research to overcome this problem. They are cloaking region based query processing methods which blur a user’s location into a cloaking region and Private Information Retrieval (PIR) based query processing methods which encrypt location data by using PIR protocol. However, the main disadvantages of existing work are high computation and communication overheads. To resolve these problems, we propose a grid-based approximate k-NN query processing algorithm by combining above two methods. Through performance analysis, we have shown that our scheme outperforms the existing work in terms of both query processing time and accuracy of the result set.