Resilient asymptotic consensus in asynchronous robust networks

Abstract

In this paper, we study the problem of reaching consensus asymptotically in the presence of adversary nodes whenever the network is asynchronous under a local broadcast model of communication. The type of adversary considered is omniscient and may collude with other adversaries to achieve the goal of disrupting consensus among the normal nodes. The main limitation on the behavior of the adversary nodes is that whenever the adversary nodes communicate with neighbors, they must broadcast their messages so that all neighbors receive the same information. The asynchronous consensus algorithm studied here uses local strategies to ensure resilience against the adversary nodes. The class of topologies studied are those that are robust. Network robustness formalizes a notion of redundancy of direct information exchange between subsets of nodes in the network, and is an important property for analyzing the behavior of resilient distributed algorithms that use only local information.