Characterizing Blockchain Interoperability Systems from an Architecture Perspective

Abstract

Blockchains are designed as closed execution environments that only support operations within their own system for security purposes. However, as the technology became popular, interoperation across different blockchains emerged as one of the most desired features to enable the creation of networks of interconnected blockchains. Towards fulfilling this need, multiple academic proposals and industry projects have been developed, but most of those systems are designed to connect specific platforms and cannot be applied to all blockchains. While there are studies that aim to provide understanding on these solutions, they are mainly focused on the cryptographic formalization and dependability of such systems. Limited attention has been paid to the system architecture and organization of such solutions. This paper aims to bridge this gap by characterizing existing cross-chain communication systems from an architecture perspective. We classify ten existing systems into four categories and develop an evaluation framework with criteria from five different aspects. We then evaluate the selected systems based on the proposed framework and present a comparative analysis between the systems in each category. We aim to provide an holistic view of state-of-practice to help developers and the blockchain community to select suitable solutions for their cross-chain communication needs.