Securing peer to peer systems using webs of trust

Most current peer-to-peer systems are designed to allow potentially millions of nodes to efficiently route messages and store data on other nodes. If some of those nodes are malicious, they have numerous opportunities for mischief, including dropping or misdirecting messages. While many of these problems can be addressed through the use of a central authority, this may not be feasible for all p2p systems. This paper considers the applicability of "web of trust" systems toward p2p overlay networks. Based on traces taken from three different web of trust systems, we show how to apply trust relationships toward limiting the damage that can be caused by malicious nodes. We show how "good" nodes can filter out malicious nodes by searching the trust graph for multiple disjoint paths from one to the other. The resulting p2p overlay exhibits robust behavior, even when a sizable percentage of the nodes are malicious