AREX: An Adaptive System for Secure Resource Access in Mobile P2P Systems

In open environments, such as mobile peer-to-peer systems, participants may need to access resources from unknown users. A critical security concern in such systems is the access of faulty resources, thereby wasting the requester´s time and energy and possibly causing damage to her system. A common approach to mitigating the problem involves reputation mechanisms; however, since reputation relies on cooperation, a reputation mechanism´s effectiveness can be significantly diminished in hostile environments. Reputation systems also require substantial communication among peers leading to: i) vulnerability to errors caused by intermittent connectivity; ii) message delivery disruptions caused by malicious peers; and iii) energy sapping message overheads. In this paper, we present AREX, a low-cost, adaptive mechanism designed to provide security for peers in hostile and uncertain environments, which are common in mobile P2P systems. AREX features an adaptive exploration strategy that increases the system´s utility for benign peers and decreases the systempsilas utility for malicious peers. AREX reduces vulnerabilities and energy costs by operating without communication between peers. Through simulation, we demonstrate AREX´s ability to reduce energy costs, protect benign peers, and diminish malicious peers´ motivation to attack in a variety of hostile environments.