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arXiv 2201.12809cs.DCcs.DS
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OverChain:使用区块链构建强大的覆盖

OverChain: Building a robust overlay with a blockchain

Vijeth Aradhya, Seth Gilbert, Aquinas Hobor

摘要:

区块链使用对等网络在对等体之间传播信息,但这些网络目前没有任何可证明的保证,例如拜占庭容错,良好的连接性和小直径。这不仅仅是一个理论问题,因为最近的工作利用了不安全的对等连接策略和弱网络同步来对比特币进行分区攻击。加密货币区块链是安全关键系统,因此我们需要有原则的算法来维护它们的网络。我们的关键见解是,我们可以利用区块链本身在对等体之间共享信息,从而简化网络维护过程。考虑到对等节点的计算资源有限,并且其中最多有一部分是拜占庭式的,我们提供了通信高效的协议来维护区块链的超立方网络,其中对等节点可以随着时间的推移加入和离开。有趣的是,我们发现我们的设计可以\emph{recover}从实质性的对抗失败。此外,尽管出现了重大的流失,但这些资产仍然存在。一个关键的贡献是加入网络的安全机制,该机制使用区块链来帮助新的对等点联系现有的对等点。此外,通过检查对等体如何加入网络,即,对于"引导服务",我们给出了一个下限,表明(在对数因子内)我们的网络可以容忍最大的流失率。事实上,我们可以为任何需要连接的完全分布式服务提供一个较低的流失率。

英文摘要:

Blockchains use peer-to-peer networks for disseminating information among peers, but these networks currently do not have any provable guarantees for desirable properties such as Byzantine fault tolerance, good connectivity and small diameter. This is not just a theoretical problem, as recent works have exploited unsafe peer connection policies and weak network synchronization to mount partitioning attacks on Bitcoin. Cryptocurrency blockchains are safety critical systems, so we need principled algorithms to maintain their networks. Our key insight is that we can leverage the blockchain itself to share information among the peers, and thus simplify the network maintenance process. Given that the peers have restricted computational resources, and at most a constant fraction of them are Byzantine, we provide communication-efficient protocols to maintain a hypercubic network for blockchains, where peers can join and leave over time. Interestingly, we discover that our design can \emph{recover} from substantial adversarial failures. Moreover, these properties hold despite significant churn. A key contribution is a secure mechanism for joining the network that uses the blockchain to help new peers to contact existing peers. Furthermore, by examining how peers join the network, i.e., the "bootstrapping service," we give a lower bound showing that (within log factors) our network tolerates the maximum churn rate possible. In fact, we can give a lower bound on churn for any fully distributed service that requires connectivity.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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