On Relating and Integrating Two Trust Management Frameworks

In this paper, we continue our line of research for defining an integrated framework for the specification and analysis of security and trust, aimed at providing the basis for the modeling and analysis of security and trust aspects of emergent dynamic coalitions (e.g., mobile ad hoc networks, peer to peer systems, web services). In particular, we consider two well-known languages: 1) the Role-based Trust-management framework (RT) and, in particular, its most basic language RT0, and 2) the transitive trust model, for defining trust and recommendation relationships. First, we show an encoding of the transitive trust model into part of RT0; then, this subset is mapped into the inference construct of the Crypto-CCS process algebra. Also, we introduce in the languages operators dealing with levels of trust. The relationships among these languages could allow us to model and analyze trust and recommendation issues in distributed systems by means of standard formal techniques, based on inference systems.