Prof. Zhang is famous for her contribution to the field of distributed systems. She is a Fellow of IEEE and the Cheung Kong Chair Professor. Prof. Zhang is now Tencent Professor of Engineering and Chair Professor of the Department of Computer Science and Engineering in Hong Kong University of Science and Technology. She received the Second-Class Award (the 3rd awardee) in Natural Sciences for Research Excellence by the State Council in 2012. She also received the Best Asia Pacific (AP) Young Researcher Award elected by IEEE Communication Society in 2004, and MIT TR100 (MIT Technology Review) World’s Top Young Innovator Award.
Recently, a team lead by Prof. Zhang from Hong Kong University of Science and Technology announced breakthroughs in the research on sharding protocol and consensus mechanism. Based on their research, the team is now working on the realization of a VISA-level public chain based on reputational sharding.
In the P2P system, nodes trust others based on their historic behavior and love to cooperate with the higher reputation nodes. Inspired by these observations, Prof. Zhang proposes a reputation-based secure, high incentive and fast blockchain system. The system measures the reputation scores of validators based on their behaviors, and leverages these scores to incent the validators and secure the system simultaneously. In terms of incentive, the validators get the reward based on their reputation scores, i.e., an honest and competent validator deserves more rewards for its contribution to the system. In terms of security, reputation-based sharding and leader selection scheme can balance the total reputation score across different shards, so that each shard has similar proportions of active, inactive, honest and malicious validators. Thus, it is more difficult for the malicious users to take control of one shard. Generally, reputation-based sharding is more secure than random-based ones. It only degrades to the random-based one with an advanced attacker in the worst case.
Prof. Zhang and the team have implemented and evaluated the system on Amazon Web Service platform. More specifically, the team set 900 c4.large EC2 instances equipped with 2 Amazon vCPUs and 3.75GB of memory from two different regions to simulate 1800 nodes. The results show the system achieves 6852 tps throughput and maintains a satisfying security level. The solution can enhance both throughout and security level of the existing sharding-based blockchain system, basically meets requirements of commercial application, i.e. a VISA-level public chain.
It is learnt that the team has submitted the research results in the form of academic paper to a world’s top conference. The team is now developing the research and application of the VISA-level public chain based on reputational sharding.