发表机构
University of Michigan, Ann Arbor, MI, USA（密歇根大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出理性无害性（RHP）概念，证明交易费用机制在有限区块容量下存在四难困境，并构造满足RHP的随机化机制，将设计从激励扩展至防无成本损害。
AI 中文摘要
交易费用机制（TFMs）在区块链中分配稀缺的区块空间。先前的研究聚焦于激励相容性（IC）：诚实行为使每个策略参与者的收益最大化。我们引入了理性无害性（RHP），它排除了那些损害诚实参与者但不降低偏离者相对于诚实行为的效用的偏离行为。仅靠IC并不能排除这种无成本的损害：在第二价格拍卖中，失败的竞标者可以提高获胜者的支付而不改变自身的收益。对于有限的区块容量k，我们刻画了同时满足RHP以及用户激励相容性（UIC）和矿工激励相容性（MIC）的TFMs。在普通模型中，即单个矿工实施拍卖，我们证明了一个严格的四难困境：不存在任何TFM能同时实现正的矿工收益、UIC、MIC以及针对矿工-用户联盟的RHP，而任意三者可以联合实现。在MPC辅助模型中，即由矿工委员会使用多方计算实施拍卖，我们构建了一个随机化的TFM，其具有正的矿工收益，并满足针对用户、矿工以及包含至多k个用户的矿工-用户联盟的UIC、MIC和RHP。随机性对于在拥塞下确认交易是必要的：在此模型中，任何满足UIC和用户RHP的确定性TFM，当提交的投标数量超过k时，不会确认任何交易。最后，在两个模型中，对于每个策略角色，IC和RHP是不可比较的：机制可以满足其中一个属性而不满足另一个。这些结果将交易费用机制设计从激励扩展到对无成本损害的保护。
英文摘要
Transaction fee mechanisms (TFMs) allocate scarce block space in blockchains. Prior work focuses on incentive compatibility (IC): honest behavior maximizes the payoff of each strategic player. We introduce rational-harm proofness (RHP), which rules out deviations that harm honest participants without reducing the deviator's utility relative to honest behavior. IC alone does not exclude such costless harm: in a second-price auction, a losing bidder can raise the winner's payment without changing its own payoff. For finite block capacity k, we characterize TFMs satisfying RHP alongside user incentive compatibility (UIC) and miner incentive compatibility (MIC). In the plain model, where a single miner implements the auction, we prove a tight tetrilemma: no TFM simultaneously achieves positive miner revenue, UIC, MIC, and RHP against miner-user coalitions, while any three are jointly achievable. In the MPC-assisted model, where a committee of miners implements the auction using multi-party computation, we construct a randomized TFM with positive miner revenue satisfying UIC, MIC, and RHP against users, miners, and miner-user coalitions containing at most k users. Randomness is necessary to confirm transactions under congestion: any deterministic TFM satisfying UIC and user RHP in this model confirms no transactions when the number of submitted bids exceeds k. Finally, IC and RHP are incomparable for every strategic role in both models: mechanisms can satisfy either property without satisfying the other. These results extend transaction fee mechanism design beyond incentives to protection against costless harm.
