DTM:A dynamic trust management model for internet computing environments

Nowadays, many novel computing technologies such as Pervasive Computing and Grid Computing have emerged to empower resource sharing and collaboration over Internet. However, trust establishment across multiple autonomous domains has become an important issue because resources are dynamic and behaviours are uncontrollable over Internet. Firstly, existing trust management solutions and systems lack of a unified model, specially the definitions of trust in several security mechanisms are inconsistent, moreover there is no formal proof on trust transitive property referring to the trust management model. Additionally, dynamic short-lived collaboration among entities frequently happens, which may require the trust relationship among collaborating entities to be changed on demand. Therefore, this paper proposes a dynamic trust management model (DTM) to support flexible trust establishment between unfamiliar entities, in which the concept of trust is formally defined based on a belief formula, and the transitive property of trust (trust chain) is proved. In this model, an event is used to describe the cause of trust relationship evolution between principals. A regular event sequence is employed to describe the resource authorization process, and a dependent sequence on regular event sequences is designed for the resource authorization process of trust negotiation. Finally, a trust management system in CROWN middleware, and some preliminary experiments are conducted and the experimental results are given and analysed.