PIDGIN: Privacy-preserving interest and content sharing in opportunistic networks

Opportunistic networks have recently received considerable attention from both industry and researchers. These net-works can be used for many applications without the need for a dedicated IT infrastructure. In the context of oppor-tunistic networks, content sharing in particular has attracted significant attention. To support content sharing, oppor-tunistic networks often implement a publish-subscribe sys-tem in which users may publish their own content and indi-cate interest in other content through subscriptions. Using a smartphone, any user can act as a broker by opportunisti-cally forwarding both published content and interests within the network. Unfortunately, opportunistic networks are faced with se-rious privacy and security issues. Untrusted brokers can not only compromise the privacy of subscribers by learning their interests but also can gain unauthorised access to the dissem-inated content. This paper addresses the research challenges inherent to the exchange of content and interests without: (i) compromising the privacy of subscribers, and (ii) provid-ing unauthorised access to untrusted brokers. Specifically, this paper presents an interest and content sharing solution that addresses these security challenges and preserves pri-vacy in opportunistic networks. We demonstrate the feasi-bility and efficiency of the solution by implementing a pro-totype and analysing its performance on smart phones