Towards Interconnected Blockchains

Abstract

Unprecedented attention towards blockchain technology is serving as a game-changer in fostering the development of blockchain-enabled distinctive frameworks. However, fragmentation unleashed by its underlying concepts hinders different stakeholders from effectively utilizing blockchain-supported services, resulting in the obstruction of its wide-scale adoption. To explore synergies among the isolated frameworks requires comprehensively studying inter-blockchain communication approaches. These approaches broadly come under the umbrella of Blockchain Interoperability (BI) notion, as it can facilitate a novel paradigm of an integrated blockchain ecosystem that connects state-of-the-art disparate blockchains. Currently, there is a lack of studies that comprehensively review BI, which works as a stumbling block in its development. Therefore, this article aims to articulate potential of BI by reviewing it from diverse perspectives. Beginning with a glance of blockchain architecture fundamentals, this article discusses its associated platforms, taxonomy, and consensus mechanisms. Subsequently, it argues about BI’s requirement by exemplifying its potential opportunities and application areas. Concerning BI, an architecture seems to be a missing link. Hence, this article introduces a layered architecture for the effective development of protocols and methods for interoperable blockchains. Furthermore, this article proposes an in-depth BI research taxonomy and provides an insight into the state-of-the-art projects. Finally, it determines possible open challenges and future research in the domain.

Blockchain Interoperability: a Feature-based Classification Framework and Challenges Ahead

“…Later on, Belchior et al [11] stated that although some critical requirements on blockchain interoperability were fulfilled primary on public blockchain solutions, private and private-topublic interoperability is still a challenge that needs further work. A more recent paper by Lohachab et al [12] states that there is a need to develop new interoperability solutions that include private and consortium blockchain networks.…”

“…In order to start developing interoperability solutions, we first needed to understand the existing ones, their definitions and features. Some interoperability frameworks and classifications exist and have classified them with quite success [9,11,12]. Unfortunately, interoperability solutions evolve very fast and classifications become quickly outdated.…”

“…Interoperability and system integration were not features provided by blockchain platforms original design, which limit their usage on other use cases. In the last years, some academic and industry efforts were performed in order to achieve interoperability between blockchain platforms [8,9,10,11,12], which have increased through the years [11].…”

“…Later works dated on 2021 include new types of solutions and a more updated survey, but they classify the same blockchain interoperability solutions with different categories. As an example, Belchior et al [11] classifies Cosmos and Polkadot as a Blockchain of blockchain solution, while Lohachab et al classifies them as a Relay solution [12]. The way in which they arrived to these results is not clear, as they do not specify the classification details in their works.…”

Applications of Blockchain in Business Processes: A Comprehensive Review

“…In this regard, there are two studies that survey BC interoperability found in [61] focusing on IoT and [80] for general BC interoperability. Compared to the former, we differentiate our survey introducing broader coverage than IoT.…”