Strange Bedfellows: Community Identification in BitTorrent
While P2P systems benefit from large numbers of interconnected nodes, each of these connections provides an opportunity for eavesdropping. Using only the connection patterns gathered from 10,000 BitTorrent (BT) users during a one-month period, the authors determine whether randomized connection patterns give rise to communities of users. Even though connections in BT require not only shared interest in content, but also concurrent sessions, they find that strong communities naturally form - users inside a typical community are 5 to 25 times more likely to connect to each other than with users outside. These strong communities enable guilt by association, where the behavior of an entire community of users can be inferred by monitoring one of its members.