Memory complexity of automated trust negotiation strategies

Abstract

Automated Trust Negotiation(ATN) has been proposed as a mechanism to establish mutual trust among strangers. Protocols and strategies to be used during ATN have also been studied. When considering the real world usage of ATN, there are many factors to be considered. One of the factors that has not been addressed by previous studies is the memory complexity of negotiation strategies. This paper analyses the memory complexities of previously proposed negotiation strategies and evaluates the average memory consumption through simulations using an ATN framework for web services. The experimental results revealed that memory complexity of Parsimonious strategy grows exponentially as the number of credentials increases, which is consistent with the theoretical analysis. As a solution, a method to reduce the memory consumption by exploiting the knowledge each entity has about the negotiation is presented. In addition, the paper presents a new criterion that enables the truncation of the negotiation to reduce the memory consumption in situations where the negotiation fails. Experiment results, which show the effectiveness of above methods in reducing the memory consumption, negotiation length are also presented. © 2009 Springer-Verlag Berlin Heidelberg.