Sidechain techniques improve blockchain scalability and interoperability, providing decentralized exchange and cross-chain collaboration solutions for Internet of Things (IoT) data across various domains. However, current state-of-the-art (SOTA) schemes for IoT multi-domain data exchange are constrained by the need for synchronous networks, hindering efficient cross-chain interactions in discontinuous networks and leading to suboptimal data exchange. In this paper, we propose AsyncSC, a novel asynchronous sidechain construction. It employs a committee to provide Cross-Blockchain as a Service (C-BaaS) for data exchange in multi-domain IoT. To fulfill the need for asynchronous and efficient data exchange, we combine the ideas of aggregate signatures and verifiable delay functions to devise a novel cryptographic primitive called delayed aggregate signature (DAS), which constructs asynchronous cross-chain proofs (ACPs) that ensure the security of cross-chain interactions. To ensure the consistency of asynchronous transactions, we propose a multilevel buffered transaction pool that guarantees the transaction sequencing. We analyze and prove the security of AsyncSC, simulate an asynchronous communication environment, and conduct a comprehensive evaluation. The results show that AsyncSC outperforms SOTA schemes, improving throughput by an average of 1.21 to 3.96 times, reducing transaction latency by 59.76% to 83.61%, and maintaining comparable resource overhead.

翻译：侧链技术提升了区块链的可扩展性与互操作性，为跨不同领域的物联网数据提供了去中心化交换与跨链协作解决方案。然而，当前物联网多领域数据交换的最先进方案受限于对同步网络的依赖，阻碍了在非连续网络中实现高效的跨链交互，导致数据交换效率欠佳。本文提出AsyncSC，一种新颖的异步侧链架构。该架构采用委员会机制，为多领域物联网数据交换提供跨链即服务。为满足异步高效数据交换的需求，我们融合聚合签名与可验证延迟函数的思想，设计了一种称为延迟聚合签名的新型密码学原语，用以构建异步跨链证明，确保跨链交互的安全性。为保证异步交易的一致性，我们提出了一种多级缓冲交易池，以保障交易顺序。我们对AsyncSC进行了安全性分析与证明，模拟了异步通信环境，并开展了全面评估。结果表明，AsyncSC性能优于现有最先进方案，吞吐量平均提升1.21至3.96倍，交易延迟降低59.76%至83.61%，同时保持了可比的资源开销。