Privacy-enhanced social-network routing

An opportunistic network of mobile nodes can be created when mobile devices work together to create an ad hoc store-and-forward architecture, with messages forwarded via intermediary encountered nodes. Social-network routing has been proposed to route messages in such networks: messages are sent via nodes in the sender's or recipient's friends list. Simple social-network routing, however, may broadcast these friends lists, which introduces privacy concerns. This paper studies mechanisms for enhancing privacy while using social-network routing. We first present a threat analysis of the privacy risks in social-network routing, and then introduce two complementary methods for enhancing privacy in social-network routing by obfuscating the friends lists used to inform routing decisions. We evaluate these methods using three real-world datasets, and find that it is possible to obfuscate the friends lists without leading to a significant decrease in routing performance, as measured by delivery cost, delay and ratio. We quantify the increase in security provided by this obfuscation, with reference to the classes of attack which are mitigated.