标题： 理性的审查攻击：用黑板破坏区块链 显示英文标题

标题： Rational Censorship Attack: Breaking Blockchain with a Blackboard

摘要： 审查弹性是区块链协议安全性的基本假设。 此外，近年来从经济和博弈论角度分析区块链安全性的方法越来越受欢迎。 在本工作中，当我们采用博弈论的视角分析区块链安全性并假设所有用户都是理性的时，我们提出了一种令人惊讶的理性审查攻击，针对区块链的审查弹性。 在我们的攻击中，一个拥有足够投票权的共谋组会审查其余节点，使得该组能够独自获得维护区块链的所有奖励。 我们表明，如果节点是理性的，协调此攻击只需要一个公共的读写黑板，并且我们使用博弈论框架对攻击进行了形式化建模。 此外，我们注意到，为了确保攻击的成功，节点需要知道共谋组所拥有的总真实投票权。 我们证明，加入理性审查攻击以及节点诚实地声明其权力的策略是在由我们的攻击引起的相应扩展形式博弈中的子博弈完美均衡。 最后，我们讨论了该攻击对区块链用户和协议设计者的影响以及一些潜在的对策。 显示英文摘要

摘要： Censorship resilience is a fundamental assumption underlying the security of blockchain protocols. Additionally, the analysis of blockchain security from an economic and game theoretic perspective has been growing in popularity in recent years. In this work, we present a surprising rational censorship attack on blockchain censorship resilience when we adopt the analysis of blockchain security from a game theoretic lens and assume all users are rational. In our attack, a colluding group with sufficient voting power censors the remainder nodes such that the group alone can gain all the rewards from maintaining the blockchain. We show that if nodes are rational, coordinating this attack just requires a public read and write blackboard and we formally model the attack using a game theoretic framework. Furthermore, we note that to ensure the success of the attack, nodes need to know the total true voting power held by the colluding group. We prove that the strategy to join the rational censorship attack and also for nodes to honestly declare their power is a subgame perfect equilibrium in the corresponding extensive form game induced by our attack. Finally, we discuss the implications of the attack on blockchain users and protocol designers as well as some potential countermeasures.