Cryptology ePrint Archive: Report 2018/754

SoK: A Consensus Taxonomy in the Blockchain Era

Juan Garay and Aggelos Kiayias

Abstract: Consensus (a.k.a. Byzantine agreement) is arguably one of the most fundamental problems in distributed systems, playing also an important role in the area of cryptographic protocols as the enabler of a (secure) broadcast functionality. While the problem has a long and rich history and has been analyzed from many different perspectives, recently, with the advent of blockchain protocols like Bitcoin, it has experienced renewed interest from a much wider community of researchers and has seen its application expand to various novel settings.

One of the main issues in consensus research is the many different variants of the problem that exist as well as the various ways the problem behaves when different setup, computational assumptions and network models are considered. In this work we perform a systematization of knowledge in the landscape of consensus research starting with the original formulation in the early 1980s up to the present blockchain-based new class of consensus protocols. Our work is a roadmap for studying the consensus problem under its many guises, classifying the way it operates in many settings and highlighting the exciting new applications that have emerged in the blockchain era.

Category / Keywords: cryptographic protocols / Consensus, Byzantine agreement, blockchain protocols, cryptographic protocols.

Original Publication (with minor differences): CT-RSA 2020

Date: received 15 Aug 2018, last revised 8 Dec 2019

Contact author: juan a garay at gmail com

Available format(s): PDF | BibTeX Citation

Version: 20191209:004924 (All versions of this report)

Short URL: ia.cr/2018/754