Blockchain interoperability is emerging as one of the crucial features of blockchain technology, but the knowledge necessary for achieving it is fragmented. This fact makes it challenging for academics and the industry to achieve interoperability among blockchains seamlessly. Given this new domain’s novelty and potential, we conduct a literature review on blockchain interoperability by collecting 284 papers and 120 grey literature documents, constituting a corpus of 404 documents. From those 404 documents, we systematically analyzed and discussed 102 documents, including peer-reviewed papers and grey literature. Our review classifies studies in three categories: Public Connectors, Blockchain of Blockchains, and Hybrid Connectors. Each category is further divided into sub-categories based on defined criteria. We classify 67 existing solutions in one sub-category using the Blockchain Interoperability Framework, providing a holistic overview of blockchain interoperability. Our findings show that blockchain interoperability has a much broader spectrum than cryptocurrencies and cross-chain asset transfers. Finally, this article discusses supporting technologies, standards, use cases, open challenges, and future research directions, paving the way for research in the area.

中文翻译：

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区块链互操作性调查：过去、现在和未来趋势

区块链互操作性正在成为区块链技术的关键特征之一，但实现它所需的知识却是零散的。这一事实使学术界和业界难以无缝地实现区块链之间的互操作性。鉴于这一新领域的新颖性和潜力，我们通过收集 284 篇论文和 120 篇灰色文献文档，构成 404 篇文档的语料库，对区块链互操作性进行了文献综述。从这 404 篇文献中，我们系统地分析和讨论了 102 篇文献，包括同行评议论文和灰色文献。我们的评论将研究分为三类：公共连接器、区块链区块链和混合连接器。每个类别根据定义的标准进一步分为子类别。我们使用区块链互操作性框架将 67 个现有解决方案分类为一个子类别，提供区块链互操作性的整体概述。我们的研究结果表明，区块链互操作性比加密货币和跨链资产转移具有更广泛的范围。最后，本文讨论了支持技术、标准、用例、开放挑战和未来的研究方向，为该领域的研究铺平了道路。