Context-Dependent Reputation Management for Soft Security in Multi Agent Systems

Mobile agent systems lack of security tools to grant access to their services to a wide range of users as open systems should do. A major issue is to prevent interactions with malicious entities. Trust concept from social science can help information systems to obtain solid social network of collaboration. We propose a flexible reputation framework with a centralized approach that manages trustworthiness of entities grouped by trust context. Members of each group share context-dependent trust opinions within the group itself, in order to form a knowledge base of reputation information. A common ontology supports generic communication, e.g. opinion sharing, and a context-dependent specific ontology is used for opinion formations. The reputations are the weighted means of opinions provided by trusted entities. That information supports the decision making and risk evaluation processes anytime entities start new relations.