The Role of Confidence for Trust-based Resilient Consensus (Extended Version)

TL;DR

This paper introduces a trust-based resilient consensus protocol for multi-agent systems that effectively handles malicious agents by incorporating confidence levels in trust observations, improving robustness without requiring initial observation windows.

Contribution

It proposes a novel consensus protocol that uses confidence parameters to enhance resilience against malicious agents without relying on initial trust observation windows.

Findings

Achieves resilient consensus despite malicious agents.

Steady-state deviation minimized by tuning confidence parameter.

Protocol validated through analytical and numerical results.

Abstract

We consider a multi-agent system where agents aim to achieve a consensus despite interactions with malicious agents that communicate misleading information. Physical channels supporting communication in cyberphysical systems offer attractive opportunities to detect malicious agents, nevertheless, trustworthiness indications coming from the channel are subject to uncertainty and need to be treated with this in mind. We propose a resilient consensus protocol that incorporates trust observations from the channel and weighs them with a parameter that accounts for how confident an agent is regarding its understanding of the legitimacy of other agents in the network, with no need for the initial observation window $T_0$ that has been utilized in previous works. Analytical and numerical results show that (i) our protocol achieves a resilient consensus in the presence of malicious agents and (ii) the steady-state deviation from nominal consensus can be minimized by a suitable choice of the confidence parameter that depends on the statistics of trust observations.