标题： 虚幻的胜利：恶意提议者如何在乐观型分片争议游戏中利用验证者激励机制 显示英文标题

标题： Hollow Victory: How Malicious Proposers Exploit Validator Incentives in Optimistic Rollup Dispute Games

摘要： 区块链系统，如以太坊，正在越来越多地采用第二层扩展解决方案来提高交易吞吐量并降低费用。一种流行的第二层方法是乐观汇总，它依赖于一种称为争议游戏的机制来进行区块提议。在这些系统中，验证者可以挑战他们认为包含错误的区块，成功的挑战会导致提议者的部分存款被转移作为奖励。在本文中，我们揭示了该机制中的一个结构性漏洞：即使赢得争议挑战，验证者也可能无法获得适当的利润。我们开发了一个形式化的博弈论模型来分析争议游戏，并分析了几种情况，包括提议者控制一些验证者的情况以及部署了二次拍卖机制以诱导更多参与的情况。我们的分析表明，在当前设计下，验证者之间的竞争压力可能不足以阻止恶意行为。我们发现，增加的验证者竞争，悖论性地由更高的奖励或参与度驱动，可以使恶意提议者通过拍卖等机制捕获价值，从而显著降低其净损失。为了解决这个问题，我们提出了诸如托管奖励机制和提交-揭示协议等对策。我们的研究结果为增强区块链网络中第二层扩展解决方案的经济安全性提供了关键见解。 显示英文摘要

摘要： Blockchain systems, such as Ethereum, are increasingly adopting layer-2 scaling solutions to improve transaction throughput and reduce fees. One popular layer-2 approach is the Optimistic Rollup, which relies on a mechanism known as a dispute game for block proposals. In these systems, validators can challenge blocks that they believe contain errors, and a successful challenge results in the transfer of a portion of the proposer's deposit as a reward. In this paper, we reveal a structural vulnerability in the mechanism: validators may not be awarded a proper profit despite winning a dispute challenge. We develop a formal game-theoretic model of the dispute game and analyze several scenarios, including cases where the proposer controls some validators and cases where a secondary auction mechanism is deployed to induce additional participation. Our analysis demonstrates that under current designs, the competitive pressure from validators may be insufficient to deter malicious behavior. We find that increased validator competition, paradoxically driven by higher rewards or participation, can allow a malicious proposer to significantly lower their net loss by capturing value through mechanisms like auctions. To address this, we propose countermeasures such as an escrowed reward mechanism and a commit-reveal protocol. Our findings provide critical insights into enhancing the economic security of layer-2 scaling solutions in blockchain networks.