Authored by:
Pouriya Zarbafian, University of Sydney
Vincent Gramoli, University of Sydney, CTO Redbelly Network
In State Machine Replication (SMR), preventing reordering attacks by ensuring a high degree of fairness when ordering commands requires that clients broadcast their commands to all processes. This is impractical due to the impact on scalability, and thus it discourages the adoption of a fair ordering of commands. Alternative approaches to order-fairness allow clients to send their commands to only one process, but provide a weaker notion of order-fairness. In particular, they disadvantage isolated processes. In this paper we introduce Aion, a set of order-fair protocols for SMR. We first leverage trusted execution environments (TEEs) to enable processes to compute the times when commands are broadcast by their issuers. We then integrate this information into existing consensus protocols to devise order-fair SMR protocols that are both leader-based and leaderless. To realise order-fairness, Aion only requires that a client sends its commands to a single process, while at the same time enabling precise ordering during synchronous periods.
This paper was co-authored by our CTO and Founder Professor Vincent Gramoli.
Professor Vincent Gramoli is a full professor at the University of Sydney. He is a researcher in the field of distributed systems and algorithms, with a focus on the design and analysis of distributed systems and algorithms for shared memory and data-centric systems, including distributed hash tables, distributed shared memory and transactional memory. He has published numerous papers in top-tier conferences and journals in the field and has received several awards for his research. He is also currently serving as the Head of Concurrent Systems Research Group at the University of Sydney.