Privacy-Preserving Mobility-Casting in Opportunistic Networks

In this paper, we introduce the notion of mobilitycast in opportunistic networks, according to which a message sent by a node S is delivered to nodes with a mobility pattern similar to that of S - collectively named place-friends. The motivation for delivering a message to place-friends stems from the fact that current social acquaintances are likely to be place-friends. Most importantly, it has been recently found that a large fraction of new social contacts comes from place-friends. After introducing mobility-cast, we present a privacypreserving mobile-cast protocol based on the MobileFairPlay platform for secure two-party computation in mobile environments. The effectiveness of the protocol in delivering messages to place-friends is demonstrated by means of simulations based on a real-world GPS trace. Finally, in the last part of the paper we present an implementation of mobile-cast on the Android platform, and test its computational performance on a number of different smartphones. Overall, the results presented in this paper show that privacy-preserving mobile-cast can be effectively implemented with current mobile phone technology.