Modal Logic for Distributed Trust
This work addresses trust modeling for distributed systems and multi-agent interactions, representing an incremental advancement in formal methods for such domains.
The authors tackled the problem of reasoning about trust in multi-agent systems by developing a modal logic framework for describing communication protocols and trust assumptions, which they applied to models like public key infrastructures and distributed systems.
We propose a method for reasoning about trust in multi-agent systems, specifying a language for describing communication protocols and making trust assumptions and derivations. This is given an interpretation in a modal logic for describing the beliefs and communications of agents in a network. We define how information in the network can be shared via forwarding, and how trust between agents can be generalized to trust across networks. We give specifications for the modal logic which can be readily adapted into a lambda calculus of proofs. We show that by nesting modalities, we can describe chains of communication between agents, and establish suitable notions of trust for such chains. We see how this can be applied to trust models in public key infrastructures, as well as other interaction protocols in distributed systems.