Institute of Information Science Academia Sinica
Topic: Fractal: A new framework for high-performance, large-scale, proof-of-stake blockchains
Speaker: Prof. 周紅生 (Department of Computer Science , Virginia Commonwealth University)
Date: 2019-07-03 (Wed) 10:30 – 12:30
Location: Auditorium 101 at IIS new Building
Host: Kai-Min Chung


I will present Fractal, a new framework for constructing high-performance, provably secure blockchains in large-scale networks. The Fractal framework incorporates several components. The first is a novel proof-of-stake protocol that is provably secure and addresses notorious challenges such as nothing-at-stake, grinding and long-range attacks. The second is a new method for achieving scalability by decoupling data distribution and data ordering to improve network throughput. Via rigorous analysis and real-world benchmarking, we show that Fractal achieves excellent block-propagation time as well as near-optimal throughput (up to 80% of the network-physical-limit). Fractal's cross-layer design can scale to 10,000 nodes across the globe and, under modest network assumptions, sustain a throughput of 3,000 tps. Finally, if time permits, I will discuss other technical components of the Fractal framework.


Hong-Sheng Zhou is an associate professor at Virginia Commonwealth University. He is also a scientist and co-founder of Fractal Platform, a new blockchain startup.
Zhou is working on multiple directions in cryptography including blockchain technologies; secure computing; voting; secure outsourcing; and extreme cryptography against strong leakage, tampering, kleptographic and quantum attacks. He has published a number of papers in top cryptography and distributed computing conferences, such as CRYPTO, EUROCRYPT, ACM CCS, and PODC, and in Journal of Cryptology.  Zhou’s research has been funded by NSF and multiple industry awards.
Zhou is a recipient of a Google Faculty Research award, and an NSF Computing Innovation Fellowship.