On Round-Optimal Randomized Consensus Protocols

Abstract: Decentralized systems constitute one of the fundamental paradigm shifts in current technology. At the core of any decentralized system lies a consensus protocol, which maintains a consistent state across different system components. In this talk, we introduce a new way to design randomized consensus protocols, and achieve for the first time a protocol with the optimal trade-off between the latency (measured as the number of rounds) and its probability of failure, solving a problem that was open for more than three decades. The protocol is conceptually very simple and decreases the probability of failure by more than a constant factor per round.

Bio: Chen-Da Liu Zhang is currently a Post Doctoral Fellow in the Cryptography and Information Security (CIS) Laboratory at NTT Research. Before that, he spent a year as a Post Doctoral Fellow at Carnegie Mellon University. He completed his Ph.D. in the Cryptography and Information Security group at ETH Zurich. He holds a master's degree in computer science from ETH Zurich, and two bachelor degrees in computer science and mathematics from Universidad Autónoma Madrid. His research interests revolve around building secure distributed systems. As such, his areas of expertise encompass both Cryptography and Distributed Computing. In particular, his interests include the areas of multi-party computation, consensus, blockchain, provable composable security, and secure quantum computation.