A plethora of different blockchain platforms have emerged in recent years, but many of them operate in silos. As such, there is a need for reliable cross-chain communication to enable blockchain interoperability. Blockchain interoperability is challenging because transactions can typically not be reverted - as such, if one transaction is committed then the protocol must ensure that all related transactions are committed as well. Existing interoperability approaches, e.g., Cosmos and Polkadot, are limited in the sense that they only support interoperability between their own subchains, or require intrusive changes to existing blockchains. To overcome this limitation, we propose PIEChain, a general, Kafka-based cross-chain communication framework. We utilize PIEChain for a practical case study: a cross-chain auction in which users who hold tokens on multiple chains bid for a ticket sold on another chain. PIEChain is the first publicly available, practical implementation of a general framework for cross-chain communication.

翻译：近年来涌现了大量不同的区块链平台，但其中许多平台独立运行。因此，需要可靠的跨链通信以实现区块链互操作性。区块链互操作性具有挑战性，因为交易通常无法撤销——即一旦某笔交易被提交，协议必须确保所有相关交易也被提交。现有的互操作性方法（例如Cosmos和Polkadot）存在局限性，它们仅支持自身子链之间的互操作性，或需要对现有区块链进行侵入性修改。为克服这一局限，我们提出PIEChain，一种通用的基于Kafka的跨链通信框架。我们将PIEChain用于一项实际案例研究：用户持有多个链上的代币，在跨链拍卖中对另一链上出售的门票进行竞价。PIEChain是首个公开可用的、通用跨链通信框架的实用化实现。