P2P Trust Model

With the in-depth researches of large scale distributed systems, such as Grid computing, Ubiquitous computing, P2P computing, Ad hoc networks, etc, system is a dynamic and cooperative model made up of multi-software serving. Under these dynamic and uncertainty environments, trust mechanism based on CA (certificate authority) in a regular PKI (pubic key infrastructure) can’t adapt to these requirements. Adaptive reputation mechanisms have proven to be essential to enforcing cooperative behavior in open environments and become to a new and hot topic of security research for these new distributed applications. For trust is subjective and fuzzy, there are big differences in trust description, evaluation, reasoning and computing in recent trust model. However, current trust models make a number of simplifying assumptions that may not necessarily hold in real networks, such as either irrational or completely rational behavior, instant propagation of reputation information and homogeneity of interactions. We argue that dropping those assumptions and allowing more degrees of freedom is necessary in order to construct more realistic and richer reputation models. We support our argument by citing reputation research done in economics, evolutionary, psychology, biology, sociology and so on, and consider models that take into account adaptive behavior changes, co-evolution of behavior, bounded rationality, and so on. We focus on constructing more realistic and less constrained reputation models that can potentially lead to construction of more secure, responsive, and cooperative networks.