Trusted Registration, Negotiation, and Service Evaluation in Multi-Agent Systems throughout the Blockchain Technology

Some recent trends in distributed intelligent systems rely extensively on agent-based approaches. The so-called Multi-Agent Systems (MAS) are taking over the management of sensitive data on behalf of their producers and users (e.g., medical records, financial investment, energy market). Therefore, trusted interactions are needed more than ever, while accountability and transparency among the agents seem crucial characteristics to be achieved. To do so, recent trends advocate the use of blockchain technologies (BCT) in MAS. The blockchain is a distributed ledger technology that can execute programmable transaction logic, and provides a shared, immutable, and transparent append-only register of all the actions happening in the network. Although a few theoretical approaches have already been proposed, the quest for such a system consolidating BCT and MAS to guarantee privacy, scalability, transparency, and efficiency continues. This paper presents a reconciling system including BCT within the dynamics of a MAS. Such a system aims at (i) building a solid ground for trusted interactions and (ii) enabling more characterizing feature-based and trustworthy ways of computing agent reputation. The system has been tested in four scenarios with different configurations (regular executions and involving down-agents or malicious behaviors). Finally, the paper summarizes and discusses the experience gained, argues about the strategic choice of binding MAS and BCT, and presents some future challenges.