AI 中文总结
研究如何降低基于领导者的BFT协议的尾部延迟问题，核心方法是基于前缀共识构建Hermes两轮旋转领导者协议，主要贡献是使过期视图能完成最终确定，且给出了具体实例化及复杂度分析。
AI 中文摘要
基于领导者的拜占庭容错（BFT）协议通过领导者来完成最终确定：如果领导者崩溃或缓慢，那么该视图将无法完成任何事情，并且结束它的超时没有好的设置。保守的超时会使每个崩溃的领导者长时间停顿；激进的超时会使仅仅缓慢的领导者的视图无效。无论哪种方式，过期的视图都会被浪费，这种权衡而非良好情况决定了尾部延迟。Hermes使过期视图能够完成最终确定。它是一种两轮旋转领导者协议，适用于部分同步下的\(n = 5f + 1\)个进程，基于前缀共识构建：投票携带按前缀关系排序的值，并且多数派要求具有可比性而非相等性。每个进程在视图开始时广播一个合理的提议并投一票，要么是在接收到领导者提议时投票，要么是在超时情况下投后备提议；不存在否决票。及时的诚实领导者会在\(2\delta\)内完成其完整提议的最终确定。否则，任何\(n - f\)票（不必匹配）会完成最重的公共前缀的最终确定。我们将Hermes实例化为一个在可用链上以及类似高速公路风格的多车道传播上的最终确定小工具，其中带有显式跳过的父相对增量提示切割使独立提议具有可比性，并且发送者索引擦除编码放大将每个视图的复杂度保持在\(O(n^2\hat{m}+\lambda n^3)\)比特和\(O(n^2)\)条消息，其中\(\hat{m}\)是高速公路中并发传播车道的数量，\(\lambda\)是安全参数。
英文摘要
Leader-based BFT protocols finalize through their leaders: a view whose leader is crashed or slow finalizes nothing, and the timeout that ends it admits no good setting. A conservative timeout turns every crashed leader into a long stall; an aggressive one voids the views of leaders that are merely slow. Either way the expired view is wasted, and this trade-off, not the good case, governs tail latency. Hermes makes expired views finalize. Hermes is a two-round rotating-leader protocol for $n=5f+1$ processes under partial synchrony built on prefix consensus: votes carry values ordered by a prefix relation, and quorums require comparability rather than equality. Every process broadcasts a justified proposal at view start and casts a single vote, for the leader's proposal upon delivery or for a fallback proposal at the timeout; there are no nullify votes. A timely honest leader finalizes its full proposal in $2δ$. Otherwise, any $n-f$ votes, which need not match, finalize the heaviest common prefix. We instantiate Hermes as a finality gadget over an available chain and over Autobahn-style multi-lane dissemination, where parent-relative delta tipcuts with explicit skips keep independent proposals comparable and sender-indexed erasure-coded amplification keeps complexity at $O(n^2\hat{m}+λn^3)$ bits and $O(n^2)$ messages per view, where $\hat{m}$ is the number of concurrent dissemination lanes in Autobahn and $λ$ the security parameter.
