A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Advanced Technologies

Thesis (M.Eng.) - Asian Institute of Technology, 2003

Trust management (TM) problem is a promising approach for authorization and access control in distributed systems according to given security policies. Aspects of TM include formulating application-independent security polices and security credential, determining whether particular set of credentials satisfies the relevant policy, and deferring trust to third parties. The core of TM consists of policy language and policy engine. In this thesis, we clarify a well-known Trust Establishment system (Herzberg et al., 2000) by transforming TPL+ language and engine to logic programming context. It is concluded that its solution for negation is very simple and so weak. Afterthat, we design and implement a Trust Management system based on logic programming. The policy language of this system is normal restricted logic language and the policy engine is extended from Fitting semantic and Stable model semantic. This algorithm is proved to be sound for Preferred extension semantic.