主题：A Two-Layer Blockchain Sharding Protocol Leveraging Safety and Liveness for Enhanced Performance

嘉宾：周永銮  丹麦哥本哈根大学 教授

时间：2024年7月9日 下午15:00-16:00

地点：华中科技大学东五楼210学术报告厅

报告摘要：

Sharding is a critical technique that enhances the scalability of blockchain technology. However, existing protocols often assume adversarial nodes in a general term without considering the different types of attacks, which limits transaction throughput at runtime because attacks on liveness could be mitigated. There have been attempts to increase transaction throughput by separately handling the attacks; however, they have security vulnerabilities. In this talk, I will introduce Reticulum, a novel sharding protocol that overcomes these limitations and achieves enhanced scalability in a blockchain network without security vulnerabilities.

Reticulum employs a two-phase design that dynamically adjusts transaction throughput based on runtime adversarial attacks on either or both liveness and safety. It consists of ‘control’ and ‘process’ shards in two layers corresponding to the two phases. Process shards are subsets of control shards, with each process shard expected to contain at least one honest node with high confidence. Conversely, control shards are expected to have a majority of honest nodes with high confidence. Reticulum leverages unanimous voting in the first phase to involve fewer nodes in accepting/rejecting a block, allowing more parallel process shards. The control shard finalizes the decision made in the first phase and serves as a lifeline to resolve disputes when they surface. Experiments demonstrate that the unique design of Reticulum empowers high transaction throughput and robustness in the face of different types of attacks in the network, making it superior to existing sharding protocols for blockchain networks.

报告人简介：

周永銮是哥本哈根大学计算机科学系（DIKU）的教授，他领导着数据管理系统实验室（DMS Lab）。他还是DIKU计算机科学硕士课程的负责人。在担任现职之前，他曾担任南丹麦大学（SDU）副教授和洛桑联邦理工学院（EPFL）博士后。他获得了新加坡国立大学（NUS）的计算机科学博士学位。他的研究兴趣涵盖数据库系统和分布式系统，最近专注于可扩展事件驱动系统。他在国际期刊和会议论文集上发表了80多篇同行评议研究论文。他是EDBT执行委员会和 SSDBM 指导委员会的成员，并担任过各种国际会议的主席，包括DEBS 2022、SSDBM 2022和 EDBT 2020。他还曾担任许多其他国际会议的项目委员会成员，包括SIGMOD、VLDB、ICDE、EDBT、CIKM和SSDBM。