Confidence and Trustworthiness in Peer-to-Peer Overlay Networks

Peer-to-peer (P2P) systems are in nature fully distributed with no centralized coordinator and objects are autonomously distributed to peers in P2P overlay networks. An acquaintance might hold obsolete, even incorrect information on objects due to the propagation delay of changed information on the objects and faults of peers. Hence, a peer has to collect correct object information only from trustworthy acquaintances which are considered to hold correct information. The subjective trustworthiness of an acquaintance shows how much the peer trusts the acquaintance. On the other hand, the objective trustworthiness of an acquaintance indicates how much other peers trust the acquaintance. In this paper, we discuss three algorithms OT1, OT2, and OT3 by which the subjective trustworthiness on the acquaintance is collected from other peers to obtain the objective trustworthiness. If a peer is confident of its own subjective trustworthiness, the peer takes the subjective trustworthiness. We evaluate the algorithms OT1, OT2, and OT3 in terms of how correct objective trustworthiness can be obtained by the algorithms.