Distributed Computing Column 81

Overview. In this edition of the column, we have an exciting contribution from Shir Cohen, Idit Keidar, and Oded Naor (Technion), who provide an in-depth perspective on communication-efficient Byzantine Agreement. With the huge popularity of blockchains, the classic area of Byzantine Agreement has seen a surge of interest, and, given the large-scale and widely-distributed deployments of such mechanisms, communication efficiency is a chief concern. This column provides a gentle introduction to the area, by rst the early work in the 80s. This provides the necessary context for the recent exciting work on communication reduction, from the King & Saia algorithm to Algorand. One very useful feature in this column's contribution is the fact that it provides a uni ed view of these results, along with the mathematical background to understand and di erentiate the underlying results. Many thanks to Shir, Idit and Oded for their contribution!