An Efficient Context-Aware Privacy Preserving Approach for Smartphones

With the proliferation of smartphones and the usage of the smartphone apps, privacy preservation has become an important issue. The existing privacy preservation approaches for smartphones usually have less efficiency due to the absent consideration of the active defense policies and temporal correlations between contexts related to users. In this paper, through modeling the temporal correlations among contexts, we formalize the privacy preservation problem to an optimization problem and prove its correctness and the optimality through theoretical analysis. To further speed up the running time, we transform the original optimization problem to an approximate optimal problem, a linear programming problem. By resolving the linear programming problem, an efficient context-aware privacy preserving algorithm (CAPP) is designed, which adopts active defense policy and decides how to release the current context of a user to maximize the level of quality of service (QoS) of context-aware apps with privacy preservation. The conducted extensive simulations on real dataset demonstrate the improved performance of CAPP over other traditional approaches

One-round privacy-preserving meeting location determination for smartphone applications

With the widely adopted GPS technology in mobile devices, users enjoy many types of location services. As a recently proposed application, determining the optimal private meeting location with an aid of a location server has been an interesting research topic. The challenge in this paper is due to the requirements of security and privacy, because user locations should not be revealed to the honest-but-curious or semi-trusted location server. Adding the security and privacy protection to a location service will inevitably introduce computational complexity and communication overhead. In order to introduce robust location service and make this location service practical, we propose an efficient optimal private meeting location determination protocol, which needs only one round communication and light computation. Our proposed protocol satisfies the requirement of location privacy against outsiders, the semi-trusted meeting location determination server, and the semi-trusted group users. In order to study the performance of our protocol in a real deployment, we simulate our scheme on smartphones. The simulation results and the performance comparison with another scheme demonstrate its advantages in communication and computation efficiency