Abstract:

Cross-chain bridge technologies in blockchain ecosystems are categorized into centralized and decentralized types. Centralized bridges， due to asset concentration， are vulnerable to attacks with potentially significant losses， while decentralized bridges align with the trustless principle but face challenges such as high resource demands， prolonged implementation cycles， and poor scalability issues. Limited research has addressed balancing single points of failure and operational efficiency in decentralized designs. To address these challenges， a semi-centralized cross-chain bridge architecture that integrates centralized and decentralized models was proposed. In this architecture， initial node services were provided by a central server， while decentralized services， including routing and staking， were facilitated by smart contracts on the blockchain. Firstly， participation of blockchain nodes was incentivized through a reward mechanism， and the trust was established via remote attestation using code signing and hash value verification. Secondly， the verified nodes were incorporated into a decentralized routing table to participate in cross-chain transaction verification and auditing. Finally， cross-chain transactions were validated using Hash Time Locked Contract （HTLC）. Experimental results on transaction costs and latency demonstrate that the proposed architecture reduces transaction latency to ［24，36］ seconds with a per-transaction cost of 403 299 gas， comparable to that of centralized cross-chain bridges； a security analysis identifies three typical cross-chain bridge attacks and corresponding solutions. The proposed semi-centralized cross-chain bridge architecture achieves performance comparable to that of centralized cross-chain bridges while maintaining the security of decentralized cross-chain bridges， balancing security， efficiency， and transaction costs in cross-chain operations.

Key words: blockchain, cross-chain bridge, Hash Time Lock Contract (HTLC), cross-chain protocol, incentive mechanism

摘要：

区块链生态系统中的跨链桥技术主要分为中心化和去中心化两类：中心化桥因资产集中，易受攻击且损失巨大；去中心化桥符合无信任原则，但资源需求高、实施周期长，且存在可扩展性差的问题。当前研究较少探讨如何在去中心化设计中平衡单点故障和运营效率，为应对这些挑战，结合中心化与去中心化模型提出一种半中心化跨链桥架构，其中由中央服务器提供初始化节点服务，由区块链上智能合约提供去中心化服务，包括路由、质押等。首先，通过激励机制鼓励区块链节点的参与，并通过代码签名和哈希值验证的远程认证建立信任；其次，验证后的节点被纳入去中心化路由表，参与跨链交易验证和审计；最后，基于哈希时间锁定协议（HTLC）验证跨链交易。针对交易成本和延时的实验结果显示，所提架构将交易延时缩短至［24，36］ s，单笔跨链交易成本为403 299 gas，与中心化跨链桥接近；通过安全性分析指出了3种典型跨链桥攻击和相应的解决方法。所提出的半中心化跨链桥架构在去中心化跨链桥的安全性基础上实现了接近中心化跨链桥的性能，可平衡跨链桥的安全性、效率和交易成本。

关键词: 区块链, 跨链桥, 哈希时间锁定协议, 跨链协议, 激励机制