CCN: Decentralized Cross-Chain Channel Networks Supporting Secure and Privacy-Preserving Multi-Hop Interactions

2025-12-03

AI Summary

Multi-hop cross-chain interactions face two key challenges: settlement failures due to transient node offline states and on-chain verification leakage of user behavioral correlations. This paper proposes R-HTLC, a decentralized cross-chain channel network protocol. It introduces a sandglass timing mechanism and a multi-path asynchronous refund strategy—first ensuring both settlement correctness and interaction unlinkability under node offline conditions. By integrating zero-knowledge proofs, off-chain coordination, and multi-hop state locking, R-HTLC achieves lightweight on-chain verification and strong privacy protection without compromising security. Experimental results demonstrate robustness against both active and passive offline failures, significantly enhancing the reliability and privacy of multi-hop cross-chain transactions.

Technology Category

• Multiagent Systems: Mechanism Design
• Natural Language Processing: Machine Translation, Multilinguality, Cross-Lingual NLP
• Machine Learning: Privacy

Application Category

• Security and Privacy: Blockchains and distributed ledgers
• Economics, Online Markets and Human Computation: Economic aspects of blockchain and cryptocurrencies
• Responsible Web: Data and user privacy-enhancing technologies for the Web

Abstract

Cross-chain technology enables interoperability among otherwise isolated blockchains, supporting interactions across heterogeneous networks. Similar to how multi-hop communication became fundamental in the evolution of the Internet, the demand for multi-hop cross-chain interactions is gaining increasing attention. However, this growing demand introduces new security and privacy challenges. On the security side, multi-hop interactions depend on the availability of multiple participating nodes. If any node becomes temporarily offline during execution, the protocol may fail to complete correctly, leading to settlement failure or fund loss. On the privacy side, the need for on-chain transparency to validate intermediate states may unintentionally leak linkable information, compromising the unlinkability of user interactions. In this paper, we propose the Cross-Chain Channel Network (CCN), a decentralized network designed to support secure and privacy-preserving multi-hop cross-chain transactions. Through experimental evaluation, we identify two critical types of offline failures, referred to as active and passive offline cases, which have not been adequately addressed by existing solutions. To mitigate these issues, we introduce R-HTLC, a core protocol within CCN. R-HTLC incorporates an hourglass mechanism and a multi-path refund strategy to ensure settlement correctness even when some nodes go offline during execution. Importantly, CCN addresses not only the correctness under offline conditions but also maintains unlinkability in such adversarial settings. To overcome this, CCN leverages zero-knowledge proofs and off-chain coordination, ensuring that interaction relationships remain indistinguishable even when certain nodes are temporarily offline.

Problem

• Addresses security risks from node offline failures in cross-chain transactions
• Solves privacy leakage issues during multi-hop blockchain interactions
• Ensures transaction correctness and unlinkability in decentralized networks

Innovation

• Decentralized network for secure multi-hop cross-chain transactions
• R-HTLC protocol with hourglass mechanism and multi-path refund
• Zero-knowledge proofs and off-chain coordination for privacy preservation