[Solution] Byzantine Cluster-Sending in Expected Constant Cost and Constant Time

Abstract

The paper introduces a new problem, namely Byzantine cluster-sending, which addresses the practical need to support the sharding of data among clusters. In the model, the local communication (within a cluster) is assumed to be free, and the global communication between clusters is expensive, hence, should be minimized. The proposed solutions that adopt probabilistic techniques improve the message complexity from previously linear in the size of the cluster involved to a constant (in expectation). All reviewers appreciate the simplicity of the solutions and the accompanied in-depth experimental evaluation. Most reviewers see the relevance in practical applications of the proposed protocols.