Secure and Efficient Data Interoperability Protocols for Multi-Blockchains Systems

The proliferation of decentralized applications across different autonomous blockchains raises the need to enable cross-chain data interoperability (CCDI). However, prior approaches for supporting CCDI often hit scalability bottlenecks regarding critical metrics, e.g., memory, or remain prone to withholding and censorship attacks. This paper proposes two protocols to implement secure and efficient CCDI under adversarial conditions. The cross-chain token exchange (CCTE) protocol for atomic swaps is proposed. It adopts a deposit mechanism, a blockchain-of-blockchains (BoB), and Merkle proofs to ensure the completion of token exchanges even under withholding attacks. It utilizes a parallelized design to support concurrent token exchanges, thereby improving its efficiency and avoiding censorship attacks that target sequential token exchanges. The CCDI protocol is proposed to support any CCDI application. It authorizes a unique BoB to execute arbitrary CCDI application logic. It integrates a “transfer and in place data update” mechanism to improve its efficiency, and this mechanism enables a blockchain update its state data items using a single transaction, without requiring any information from other blockchains. Moreover, the CCDI protocol integrates a state data migration scheme, which supports a user to migrate its state data item to censorship-resilient blockchains, and incorporates a malicious user nodes elimination scheme, which enables the updates of state data items in a CCDI process even under withholding attacks. Systematic performance evaluations are conducted to compare the two protocols with existing ones. The CCTE protocol reduces latency by at least 52% compared to existing protocols under probabilistic consensus setting. The CCDI protocol outperforms prior protocols, lowering communication cost by 59%, computation overhead by 41%, memory burden by 12%, and latency cost by 33%.