中文摘要：

连续查询作为基于位置服务中常见的服务类型之一,为人们的生活和工作带来了巨大的便利.最近几年,针对位置服务中的隐私保护引起了学术界研究者的广泛关注.然而,现有在道路网络上的位置隐私保护工作大多针对快照查询提供隐私保护.如果直接将这些算法应用于连续查询,由于连续查询中位置频繁更新,将同时产生连续查询隐私泄露和精确位置的泄露.由于网络拓扑的存在,移动用户的运动在一段时间内具有时空相似的特点.利用连续查询用户的时空相似性,提出了一种在道路网络上基于时空相似性的连续查询隐私保护算法.通过采取分组策略构造匿名集和K-共享机制,提出了一种启发式宽度优先用户搜索算法HBFS来构造匿名用户集,并提出了一种连续时刻内匿名路段集生成算法CSGA生成匿名路段集合,可以同时防止连续查询攻击和位置依赖攻击.最后,采用4个评价标准对算法进行了一系列实验,验证了算法的有效性.

英文摘要：

Continuous queries are one of the most common queries in location-based services （LBSs）, although particularly useful, such queries raise serious privacy concerns. However, most of the existing location cloaking approaches over road networks are only applicable for snapshots queries. If these algorithms are applied on continuous queries directly, due to continuous location frequently updated, continuous query privacy will be disclosed. Moreover, combined with the network topology and other network parameters （limited speed etc. ） , the attackers are knowledgeable, which can easily lead to precise location privacy disclosure. We observe that mobile objects have similar spatial and temporal features due to the existing of network topology. In order to resist continuous query attacks and location-dependent attacks simultaneously, we propose a continuous queries privacy protection algorithm based on spatial-temporal similarity over road networks. The algorithm adopts user grouping and K-sharing privacy requirement strategies to constitute cloaking user sets, which is used to resist continuous queries attack. Then, with the same premise of cloaking user sets, a continuous cloaking segment sets generating algorithm is proposed to resist location-dependent attacks, which makes a balance between location privacy and service quality. Finally, we conduct series of experiments to verify our algorithm with four evaluation measures, and the experimental results show the effectiveness of the proposed algorithm.