PIDGIN: Privacy Preserving Interest and Content Sharing in Opportunistic Networks

Opportunistic networks have recently received considerable attention from both industry and researchers. These networks can be used for many applications without the need for a dedicated IT infrastructure. In the context of opportunistic networks, the application to content sharing in particular has attracted specific attention. To support content sharing, opportunistic networks may implement a publish-subscribe system in which users may publish their own content and indicate interest in other content through subscription. Using a smartphone, any user can act as a broker by opportunistically forwarding both published content and interest within the network. Unfortunately, despite their provision of this great flexibility, opportunistic networks raise serious privacy and security issues. Untrusted brokers can not only compromise the privacy of subscribers by learning their interest but also can gain unauthorised access to the disseminated content. This paper addresses the research challenges inherent to the exchange of content and interest without: (i) compromising the privacy of subscribers and (ii) providing unauthorised access to untrusted brokers. Specifically, this paper presents an interest and content sharing solution that addresses these security challenges and preserves privacy in opportunistic networks. \%RA that addresses these security challenges. We demonstrated the feasibility and efficiency of this solution by implementing a prototype and analysing its performance on real smart phones.