A trajectory privacy-preserving scheme based on query exchange in mobile social networks

With the increase in the number of active location-based service (LBS) users, protecting the privacy of user trajectory has become a significant concern. In this paper, we propose a deviation-based query exchange (DQE) scheme that obfuscates the users’ query point to mitigate trajectory disclosure in mobile social networks (MSNs). The user finds a best matching user (BMU) in an MSN to exchange queries when a query request is issued. The DQE scheme can prevent the attacker from reconstructing the user’s trajectory by collecting data from the LBS server which records only the user’s ID and his BMUs’ locations (fake locations). By virtue of the private matching algorithm based on the matrix confusion, the DQE scheme allows LBS users to enjoy the service while preserving their privacy. In order to test the effectiveness and efficiency of the proposed scheme, we carried out extensive security and performance analyses under various conditions. The results of the experiments show that the proposed DQE scheme can protect users’ trajectory privacy effectively and reduce the overhead of the LBS server.