Fuzzy Approaches to Trust Management

TLDR: The term trust is used to denote a user’s willingness to start a transaction with a given partner p, while the term reputation will be used to quantitatively express a user's judgment about previous transactions with p.

Abstract: Automatic trust management over the global information infrastructure has become an essential requirement in modern economy, where unknown parties can interact, at different levels of anonymity for the purpose of acquiring or offering services [29]. The e-business research community has proposed several trust and reputation models for open environments such as electronic marketplaces as a measure of the reliability of participants (for an early survey, see [21]). This notion of trust intuitively incorporates a certain degree of uncertainty. In this paper we adopt this community’s notation conventions as put forward in [18] and [16], where a consistent terminology is proposed. Namely, we shall use term trust to denote a user’s willingness to start a transaction with a given partner p, while the term reputation will be used to quantitatively express a user’s judgment about previous transactions with p. The security research community has developed a distinct, though closely related, notion of trust. Namely, it considers trust management as a development of existing access control (AC) models, whose policies express authorizations granted to subjects for accessing resources. In trust systems, policies specify which credentials signed by a trusted third party are needed to access a given resource.