Two Types of Trustworthiness of Acquaintances in Peer-to-Peer (P2P) Overlay Networks

Soichi Sawamura,Ailixier Aikebaier,Makoto Takizawa,Admir Barolli,Valbona Barolli

doi:10.1109/bwcca.2010.90

Abstract

Peer-to-peer (P2P) systems are in nature fully distributed with no centralized coordinator. A peer p s has to collect correct object information from trustworthy acquaintances which are considered to hold correct information. We consider two types of trustworthiness. First, the subjective trustworthiness st st on an acquaintance p t shows how much the peer p s trusts the acquaintance p t . The objective trustworthiness ot st on an acquaintance p t indicates how much other peers trust the acquaintance p t . In this paper, we discuss three algorithms OT1, OT2, and OT3 for a peer p s to obtain the objective trustworthiness ot st on the acquaintance p t . A peer p s collects subjective trustworthiness on an acquaintance p t from peers and obtain the average value as the objective trustworthiness. In the algorithm OT1, a peer p s tries to find every acquaintance of a target acquaintance p t in a type of flooding algorithm. Here, it takes time and more number of messages are transmitted. On the other hand, the peer p s sends request messages only to the acquaintances to reduce the number of messages in the algorithms OT1 and OT2. In OT2, only acquaintances which the peer p s can trust are considered. We evaluate the algorithms in terms of how correct objective trustworthiness can be obtained.

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