Chinese Journal of Computers   Full Text
Title	DTM: A Dynamic Trust Management Model for Internet Computing Environments
Authors	LI Jian-Xin HUAI Jin-Peng LI Xian-Xian LIN Li
Address	(School of Computer Science and Engineering, Beihang University, Beijing 100191)
Year	2009
Issue	No.3(493—505)
Abstract &   Background	Abstract 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. Keywords Internet computing; trust model; trust management; trust negotiation; credential; security policy Background This work is supported by the National Natural Science Funds for Distinguished Young Scholar under grant No.60525209; National Basic Research Program of China (973 Program) of China under grant No.2005CB321803 and the National High Technology Research and Development Program (863 Program) of China under grant No.2007AA01Z426 and No.2007AA01Z120. These projects aim to facilitate virtual computing and services computing across many organizations, and enable resources sharing and dynamic collaboration among a large scale of resources. However, the distributed systems have gradually evolved from closed and tight-coupled style to open and loosely coupled style, and resources are dynamic and behaviors are uncontrollable over Internet. Therefore, several security and trust challenges should be addressed in these projects and systems. The team has made important progress, amongst of which is the trust management framework for internet computing, which can be used to build trust relationship among resource consumers and providers across multiple organizations. Some trust negotiation protocols and algorithms are also investigated in this framework for information privacy protection. In this paper, authors propose a dynamic trust management model (DTM) to support flexible trust establishment between 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. A trust management system has been implemented and some preliminary experiments results show it is feasible.