Existing permissioned blockchains often rely on coordination-based consensus protocols to ensure the safe execution of applications in a Byzantine environment. Furthermore, these protocols serialize the transactions by ordering them into a total global order. The serializability preserves the correctness of the application's state stored on the blockchain. However, using coordination-based protocols to attain the global order of transactions can limit the throughput and induce high latency. In contrast, application-level correctness requirements exist that are not dependent on the order of transactions, known as invariant-confluence (I-confluence). The I-confluent applications can execute in a coordination-free manner benefiting from the improved performance compared to the coordination-based approaches. The safety and liveness of I-confluent applications are studied in non-Byzantine environments, but the correct execution of such applications remains a challenge in Byzantine coordination-free environments. This work introduces OrderlessChain, a coordination-free permissioned blockchain for the safe and live execution of I-confluent applications in a Byzantine environment. We implemented a prototype of our system, and our evaluation results demonstrate that our coordination-free approach performs better than coordination-based blockchains.

翻译：现有许可型区块链常依赖基于协调的共识协议，确保拜占庭环境下应用的安全执行。这些协议通过将交易排序为全局有序序列实现序列化。序列化机制保障了区块链中存储的应用状态正确性。然而，采用协调型协议实现全局交易序可能限制吞吐量并引发高延迟。相比之下，存在与应用层级正确性要求相关的、不受交易顺序影响的特性，即不变汇合性（I-汇合）。I-汇合应用能够以无协调方式执行，相较于协调型方法可显著提升性能。当前针对非拜占庭环境下I-汇合应用的安全性与活跃性已有研究，但在拜占庭无协调环境中正确执行此类应用仍是挑战。本文提出OrderlessChain——一种面向拜占庭环境中I-汇合应用安全且活跃执行的无协调许可型区块链。我们实现了系统原型，评估结果表明，本方案在性能上优于协调型区块链。