A Location Correlation Differential Privacy Extension Scheme Based on User Spatiotemporal Characteristics

With the popularity of mobile terminals with GPS functions, location-based services are widely used, and all kinds of user information attached to the location are facing the risk of disclosure, and privacy protection is being challenged. In current researches, it is usually assumed that the locations of different users are independent of each other. However, in real world, the locations of different users have some certain internal correlation. Even if the locations of a single user are well protected, attackers can still mine user privacy through the correlation analysis of locations. To solve the above problems, this article proposes a multiuser location-correlated differential privacy extension scheme under strict privacy budget. In this scheme, we first extract the user spatiotemporal characteristics by mining the stay points and stay areas from trajectories based on locations with timestamps, and then, we calculate the correlation degree among users using the Jaccard correlation coefficient according to the spatiotemporal characteristics, and further, we realize the adaptive differential privacy protection of different users by introducing the concept of individual correlation sensitivity, and finally, we design the differential privacy extension method to protect sensitive locations in the stay areas. Experimental results show that, compared with the existing methods, our proposed scheme not only can improve the usability of the trajectories after privacy protection, but also can enhance the privacy protection of the sensitive locations in the stay areas.