Trust in Opportunistic Networks

Opportunistic networks enables mobile users to participate in social interactions through applications such as content distribution, flea-market, micro-blogs and round based games. To interact securely, the establishment of trust is vital in a distributed environment. Trust is required to validate an identity and avoid sybil users, select trustworthy interaction partners or to collect useful opinions in a recommender system. Different forms of trust, either based on a social connection (friend), frequent encounter (familiar) or similar interests, can be harnessed in order to best suit the different requirements. Algorithms are proposed in order to evaluate different forms of trust in a distributed manner and combine them for different requirements. Complexity, trust propagation characteristics and security issues are discussed and thoroughly analyzed using synthetic models and real world mobility traces.