Resilient consensus for multi-agent systems subject to differential privacy requirements
This work provides a distributed algorithm for multi-agent systems that simultaneously handles adversarial faults and differential privacy, a novel combination for control theory and privacy communities.
The paper addresses resilient consensus in multi-agent systems with faulty agents while ensuring differential privacy of initial conditions. The proposed DP-MSR algorithm achieves consensus under (2f+1)-robust topologies with up to f faulty agents, and privacy is tunable based on network degree.
We consider multi-agent systems interacting over directed network topologies where a subset of agents is adversary/faulty and where the non-faulty agents have the goal of reaching consensus, while fulfilling a differential privacy requirement on their initial conditions. To address this problem, we develop an update law for the non-faulty agents. Specifically, we propose a modification of the so-called Mean-Subsequence-Reduced (MSR) algorithm, the Differentially Private MSR (DP-MSR) algorithm, and characterize three important properties of the algorithm: correctness, accuracy and differential privacy. We show that if the network topology is $(2f +1)$-robust, then the algorithm allows the non-faulty agents to reach consensus despite the presence of up to $f$ faulty agents and we characterize the accuracy of the algorithm. Furthermore, we also show in two important cases that our distributed algorithm can be tuned to guarantees differential privacy of the initial conditions and the differential privacy requirement is related to the maximum network degree. The results are illustrated via simulations.