Logical clocks are a fundamental tool to establish causal ordering of events in a distributed system. They have been used as the building block in weakly consistent storage systems, causally ordered broadcast, distributed snapshots, deadlock detection, and distributed system debugging. However, prior logical clock constructs fail to work in a permissionless setting with Byzantine participants. In this work, we introduce Chrono, a novel logical clock system that targets an open and decentralized network. Chrono introduces a new logical clock construct, the Decaying Onion Bloom Clock (DOBC), that scales independently to the size of the network. To tolerate Byzantine behaviors, Chrono leverages non-uniform incrementally verifiable computation (IVC) to efficiently prove and verify the construction of DOBC clocks. We have applied Chrono to build two decentralized applications, a weakly consistent key-value store and an anti-censorship social network, demonstrating the power of scalable, verifiable causality in a decentralized network.

翻译：摘要：逻辑时钟是分布式系统中建立事件因果顺序的基本工具，已被用作弱一致性存储系统、因果序广播、分布式快照、死锁检测和分布式系统调试的构建模块。然而，先前的逻辑时钟构造无法在存在拜占庭参与者的无许可环境下运行。本文提出Chrono——一种面向开放去中心化网络的新型逻辑时钟系统。Chrono引入了新的逻辑时钟构造——衰减洋葱布隆时钟（Decaying Onion Bloom Clock，DOBC），其规模可独立于网络大小进行扩展。为容忍拜占庭行为，Chrono利用非均匀增量可验证计算（IVC）高效地证明和验证DOBC时钟的构造。我们已将Chrono应用于构建两个去中心化应用——弱一致性键值存储和抗审查社交网络——展示了去中心化网络中可扩展、可验证因果性的强大能力。