Extensive Form Game Analysis Based on Context Privacy Preservation for Smart Phone Applications

The sensing capabilities of the smart phones gave birth to context-aware applications, which can provide personalized services based on users’ contexts. Since context-aware applications may sell contexts to some malicious third-parties, the exposure of contexts will handicap the development of context-aware applications in large scale. Nevertheless, it is challenging to solve the context privacy issue, because the users of the context-aware applications should trade off between service quality and privacy exposure. Nowadays, most privacy protection techniques for mobile applications neglect the context preservation. Meanwhile, limited work on context privacy doesn’t consider the applications’ strategies, which are key factors on user’s context privacy preservation. In this paper, we make a tradeoff analysis on behaviours of the user, the application and the adversary, and then we use extensive form game to formulate the decision-marking process of these three parties. After constructing payoff functions for them, we solve and analyse their Nash equilibriums. Our study shows that the key of context privacy preservation is to establish a sound reputation mechanism for context-aware applications, through which the issue of context privacy can be eliminated utterly. As a consequence, a trust between users and mobile applications can be built.