Research On Location Privacy Preserving Technique For Location-based Service

Location-based services (LBS) means that mobile telecommunications operators obtain use’s position coordinates through GPS positioning or base station positioning to provide users with a variety of value-added information services. With the rapid development of wireless location technologies and mobile Internet, location-based services have become popular recently. Users are available to obtain a rich variety of location-based services through mobile phones and other smart devices, such as navigation, making friends, looking for points of interest nearby and microblogging sign. However, with a variety of convenient, users also face the risk of exposure location while enjoying LBS. When a user requests LBS, he needs to send his location to the server. If there is system vulnerability in the server, or insider misuse the information of position, the user is facing security threats in location privacy exposure. Therefore, how to protect the user’s location privacy while obtaining service information seem important. This paper makes the following contributions in privacy protection for location-based services.First, for distributed collaborative scheme, information sharing efficiency is relatively low problem; we present a privacy preserving strategy based on an active diffusion mechanism. The sharing mechanism of location service information in the neighborhood was introduced to reduce the dependence of users on LBS server, thereby resisting the private information disclosure.Secondly, there are security risks in introducing an anonymizer in k-anonymity. To solve this problem, we propose a k-anonymity location privacy protection method with coordinate transformation. When a user needs location services, he sends his location using coordinate transformation to anonymous server. Anonymous server constructs an anonymous region without knowing the use’s real location.Finally, in the continuous queries, exposure of the trajectory and ID can reveal much information about uses. We proposed trajectory privacy protection methods based on l-trajectory. Generate the trajectory database through road network. The system construct anonymous region using the user’s true trajectory and l-1 trajectory. Then launch the query. The location server cannot tell the user’s true trajectory, so as to protect the user’s trajectory privacy.