关键词: 基于位置的服务（LBS）连续查询, 隐私保护, 用户协作, 轨迹聚类, 假查询

Abstract:

In reality, users usually submit queries continuously to LBS providers, inevitably, some background information, such as time sequence of query, location area, moving trend, is collected and analyzed by the attackers to obtain the real location or trajectory, which will lead to the exposure of user’s habits and other privacy information. In this paper, a trajectory-clustering based privacy protection method is proposed for continuous query application. The core of the method is to design an effective mechanism for constructing anonymous region, on the basis of the collaboration of the neighboring users. During the query process, users firstly retrieve the target results from the shared cache, if it missed, then it launches a query request to the LBS server. Meanwhile, a location updating algorithm for the adjacent users is proposed to improve the collaboration efficiency and guarantee the availability of cache information. Besides, for cache hitting, a region of interest extraction algorithm based on density clustering is utilized to generate fake query with high confusion to disturb the order of the whole query sequence, thereby enhancing the performance of trajectory privacy protection. The experimental results show that the time cost of continuous query is reduced, and the confusion degree is improved at the same time.

Key words: Location Based Service（LBS） continuous query, privacy protection, collaboration, trajectory clustering, fake query