A Survey on Blockchain Interoperability: Past, Present, and Future Trends
This survey addresses the fragmented knowledge in blockchain interoperability for academics and industry, but it is incremental as it primarily reviews and synthesizes existing work rather than introducing new methods.
The authors conducted a literature review on blockchain interoperability by analyzing 332 documents, including 262 papers and 70 grey literature sources, to address the fragmented knowledge in this emerging domain. They classified studies into three categories—Cryptocurrency-directed interoperability approaches, Blockchain Engines, and Blockchain Connectors—and found that blockchain interoperability extends beyond cryptocurrencies, providing a holistic overview and future research directions.
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 seamlessly achieve interoperability among blockchains. Given the novelty and potential of this new domain, we conduct a literature review on blockchain interoperability, by collecting 262 papers, and 70 grey literature documents, constituting a corpus of 332 documents. From those 332 documents, we systematically analyzed and discussed 80 documents, including both peer-reviewed papers and grey literature. Our review classifies studies in three categories: Cryptocurrency-directed interoperability approaches, Blockchain Engines, and Blockchain Connectors. Each category is further divided into sub-categories based on defined criteria. We discuss not only studies within each category and subcategory but also across categories, providing a holistic overview of blockchain interoperability, paving the way for systematic research in this domain. Our findings show that blockchain interoperability has a much broader spectrum than cryptocurrencies. The present survey leverages an interesting approach: we systematically contacted the authors of grey literature papers and industry solutions to obtain an updated view of their work. Finally, this paper discusses supporting technologies, standards, use cases, open challenges, and provides several future research directions.