Defending Against Traffic Analysis in Wireless Networks through Traffic Reshaping

Traffic analysis has been exploited by attackers to threaten user privacy in wireless networks. As an example, a user's on line activities may be exposed to strangers, even if the traffic is encrypted. However, the existing defense mechanisms against traffic analysis, such as packet padding and traffic morphing, are inefficient because they add noise traffic to blur the traffic features, therefore introducing significant overhead. In this paper, we propose the traffic reshaping technique to thwart traffic analysis. It creates multiple virtual media access control (MAC) interfaces over a single wireless card, dynamically schedules packets over these interfaces, thereby reshaping the packet features on each virtual interface. Hence, features of the original traffic are obscured and unavailable for the adversary to infer users' on line activities. Unlike the existing solutions, traffic reshaping enhances privacy protection without incurring overhead in items of adding noise traffic. We evaluate the performance of traffic reshaping through trace-based experiments. The results show that traffic reshaping is effective and efficient in defending against the traffic analysis attacks.