Location Privacy-Preserving Scheme Based on Multiple Virtual Maps

With the popularity of mobile devices, users are accustomed to enjoying abundant services which base on location information. On the other side, attackers can infer sensitive properties of users, such as the hobbies and habits, from location information. In order to protect the users’ location information privacy while enjoying the location service, many effective schemes are proposed. The traditional approach protects users’ location privacy by introducing a trusted third party, but it is difficult to find a fully trusted third party. An untrusted third party collects and obtains the user’s location information, thereby revealing users’ privacy. In this paper, we employ a fourth party to protect the privacy of users, where the fourth party sends to the users and the server multiple sets of urban distribution maps based on seeds without knowing the distribution of users. The map provides a mapping relationship between user location information and virtual location information. The fourth party divides the users’ service into two steps. First, the virtual location space is provided through the map. Second, users are allowed to send requests to the server through the third party in the virtual map space. The server returns the location of the points of interest in the virtual space. The virtual space provided by the fourth party makes it possible to prevent the users’ location information from being leaked even if the third party is attacked. The experimental results show that our method improves the quality of service under the premise of protecting privacy.