A Global Clock Model for the Consortium Blockchains We propose a global clock model to achieve time synchronization for consortium blockchains. Based on the existing consortium blockchain framework, a global clock service node is added. We use the Byzantine faulttolerant algorithm to ensure the stability of the global clock node services. In addition, Cristian and Berkeley time synchronization algorithms are used to improve the confirmation of timestamp information, so as to achieve strong consistency of consensus time. This method can strike a balance between the transaction performance and the timestamp consistency requirements. This method meets the time accuracy requirements of practical business applications, and effectively benefits the promotion of blockchain technology in timesensitive business scenarios.

ResilientDB: Global Scale Resilient Blockchain Fabric Recent developments in blockchain technology have inspired innovative new designs in distributed resilient database systems. At their core, these database systems typically use Byzantine faulttolerant consensus protocols to maintain a common state across all replicas, even if some replicas are faulty or malicious. Unfortunately, existing consensus protocols are not designed to deal with geoscale deployments in which many replicas spread across a geographically large area participate in consensus. To address this, we present the GeoScale Byzantine FaultTolerant consensus protocol (GeoBFT). GeoBFT is designed for excellent scalability by using a topologicalaware grouping of replicas in local clusters, by introducing parallelization of consensus at the local level, and by minimizing communication between clusters. To validate our vision of highperformance geoscale resilient database systems using GeoBFT, we implement GeoBFT in our efficient ResilientDB blockchain and database fabric. We show that GeoBFT is not only sound and provides great scalability, but also outperforms stateoftheart consensus protocols by a factor of six in geoscale deployments.