Leveraging trust and distrust for sybil-tolerant voting in online social media
Nitin Chiluka, Nazareno Andrade, Johan A. Pouwelse, Henk J. Sips · 2012
Due to open membership access, voting on content items in online social media (OSM) is susceptible to Sybil attacks. Malicious attackers can create multiple Sybil identities to outvote the real users of the system. This work proposes a mechanism to defend against such an attack by leveraging (i) trust which is inherent in the social network among users in OSM, and (ii) distrust between honest users, who identify some of the spam content items, and the Sybil identities who promoted them. Modeling trust and distrust in the system as a signed network, our method proceeds in two phases. First, we identify nodes and edges that constrain paths along positive edges between the endpoints of each negative edge. Second, we limit the votes from Sybil voters whose paths to honest nodes pass across these bottlenecks. Our simulation results on datasets of popular OSM show both the feasibility of incorporating distrust alongside trust to defend against Sybil attacks, and that our method outperforms the state-of-the-art approach, SumUp.