Research Seminar by LIU Huiwen | From Paxos to PoX – An Evaluative Framework for Distributed Consensus Algorithms

Distributed ledger technology (DLT), initially fueled by the boom of Bitcoin, has started to attract increasing attention due to its great promise and potential for massive applications where a trusted third party is no longer needed. DLT distinguishes itself from traditional distributed databases with a decentralized, immutable and self-organized ledger system, which hinges upon its most important technical component --- distributed consensus algorithm. A consensus algorithm serves to make sure a valid agreement is reached among a group of mutually distrusted nodes continuously. Widely studied by academia and industry for closed distributed system, this technology’s application to open-access DLT-based system has revitalized the field and led to a plethora of new designs. The inherent complexity of consensus protocols and their dramatic evolution makes it hard to sketch the design landscape. To address this challenge, we firstly conduct a comprehensive study of consensus protocols in DLT, and then design a novel evaluative framework to systematically analyze the resilience, performance and governance of various consensus protocols. Based on the trade-off comparison of various different attributes of the existing consensus protocols in such a framework, distributed ledger system designers would be able to integrate our evaluative framework with their system capabilities to choose the most appropriate and efficient consensus protocol for their applications.