The blockchain is an emerging technology which has the potential to improve many information systems. In this regard, the applications and the platform they are built on must be able to connect and communicate with each other. However, the current blockchain platforms have several limitations, such as lack of interoperability among different systems. The existing platforms of blockchain applications operate only within their own networks. Even though the underlying technology is similar, it relies on centralized third-party mediators to exchange or retrieve information from other blockchain networks. The current third-party intermediaries establish trust and security by preserving a centralized ledger to track ‘account balances’ and vouch for a transaction’s authenticity. The inability for independent blockchains to communicate with one another is an inherent problem in the decentralized systems. Lack of appropriate inter-blockchain communication puts a strain on the mainstream adoption of blockchain. It is evident that blockchain technology has the potential to become a suitable solution for some systems if it can scale and is able to cross communicate with other systems. For the multisystem blockchain concept to become a reality, a mechanism is required that would connect and communicate with multiple entities’ blockchain systems in a distributed fashion (without any intermediary), while maintaining the property of trust and integrity built by individual blockchains. In this article, we propose a mechanism that provides cross-chain interoperability using transactions.

Interoperability is identified as one of the major design constraints for blockchain technology. Cross-blockchain technology is fast evolving as the demand for value transfer among different blockchain systems is growing. A generic cross-blockchain design methodology for interoperability requires a set of suitable components to facilitate the integration process. One of the main challenges in the integration is to protect the integrity of the shared data. Various integration systems and their components may operate with different underlying security assumptions and this may lead to compromise of the overall security. In this paper we review the latest advancement in blockchain integration systems and provide a comprehensive analysis of integration characteristics for cross-blockchain technology and then define the essential components and modes of integration. Based on the outcome of our review, we propose a novel integration design decision framework that identifies key assumptions and critical characteristics of the cross-blockchain technology. The proposed framework facilitates the best-practice decision-making process. This reduces the potential for design errors and the associated security risks and performance degradation of the overall system.

Blockchain systems rely on miners to produce blocks, who solely build blocks for their financial benefit. Within the competitive market system, only correct blocks get accepted, which ensures security of the network. As financial applications migrate into the blockchain, miners in this privileged position have identified ways to extract additional revenues (known as MEV) that affect users and the overall security of the system. A possible direction for current research to resolve this exploitation is to separate the sequencing (building) and execution (mining/proposing) of transactions (PBS model). However, a weaker point of this model is the trust assumption between participants and the incentive model. This paper proposes a concept of separate incentive schemes for the work various participants conduct in their own interests.