中文摘要：

随着位置探测设备[例如便携式电话、全球定位系统（Global Positioning System,GPS）、无线射频识别（Radio Frequency Identification,RFID）等]的广泛使用,使得基于位置服务（Location-Based Services,LBS）日益受到人们的关注.LBS在给移动用户带来方便的同时,也带来了位置隐私泄漏的风险.已有的隐私保护策略通过位置泛化,把用户所在的位置坐标泛化为一个圆形或者矩形的隐匿区域,使得用户的位置很好地隐藏在这个区域中.但实际应用中,用户需要的隐匿区域往往是和实际地形相关的,并不一定是矩形或者圆形;相反使用圆形或矩形作为隐匿区域会增加无效区域的比例,降低位置信息的精度.基于已有系统的不足,本文设计实现了一个基于多边形隐匿区域的LBS系统.该系统允许用户自定义多边形隐匿区域,并基于LBS中心服务器,对用户的位置隐私进行双重保护.最后的性能测试说明了该系统的有效性.

英文摘要：

With the broad range of application of location detected device such as mobile phone, GPS and RFID etc, the researchers have paid more and more attention to the location-based serv ices （LBS）. Though LBS brings convenience to us, it also rises up the risk of location privacy leakages. The existing LBS systems transform the users＇ locaiton into a rectangle or circle cloaking region by location generalization. Then, the users＇ location can be hidden in the cloaking region to achieve the purpose of protecting the users＇ loeaiton privacy. However, in practical applications, the cloaking region may he related to the actual landform for the users＇ location, it may not be a rectangle or circle region. In fact, a rectangle or circle region even may result in the increase of invalid region and reduce the location information accuracy. In this paper, based on the shortcoming of existing systems, we design and implement a new system in which the user can define the polygonal cloaking region based on actual landform. At the meantime, the system can provide a double protection for the users＇ location privacy. The system performance tests show the effectiveness of the propsed system.