Themis共识扩展v1：特定应用区块链中通过随机延迟执行和意图隐藏交易减轻MEV
Themis Consensus Extension v1: MEV Mitigation by Randomized Delayed Execution and Intent-Hiding Transactions in Application-Specific Blockchains
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中文总结 AI 辅助
研究特定应用区块链中MEV问题，提出Themis Consensus Extension v1，通过随机延迟执行和意图隐藏交易减轻MEV，分析多种情况，记录基于Aura的Substrate实现及后续转变，保留原始提案并明确假设。
中文摘要 AI 辅助
最大可提取价值（MEV）产生于特权参与者为私利选择、排除、插入或重新排序待处理交易之时。我们详细说明了并分析了Themis共识扩展v1，它于2021年由Mangata首次发布。该设计将通过重新排序进行的价值提取（VER）与通过拒绝进行的价值提取（VED）区分开来。对于VER，块构建和执行在连续的生产者之间进行：一个生产者提交一组交易集,下一个生产者生成一个可公开验证、确定性且先前不可预测的种子，并执行由种子确定、保持依赖关系的排列。对于选择性VED，用户可为指定的构建者和执行者加密交易。构建者移除外层并提交不透明的内部密文；执行者仅在提交后才揭示并执行明文。在自私但不勾结的验证者、低于底层共识故障阈值的对手、安全加密以及可问责的角色表现的情况下，该构建限制了提交后单方面的排序控制，并向中继和构建者隐藏交易意图。它不提供发送顺序或接收顺序公平性、完全审查抗性、对构建者 - 执行者勾结的抗性或每笔交易的价格保证。我们分析了概率提取、垃圾邮件、依赖交易、解密活性、会话边界、完全拒绝和阈值联盟。我们还记录了基于初始Aura的Substrate实现及其随后向基于BABE的sr25519/VRF种子路径的转变，以及延迟执行、Fisher - Yates洗牌和Xoshiro256++。结果保留了原始提案，同时将其主张缩小到明确的假设。
英文摘要
Maximal extractable value (MEV) arises when privileged participants select, exclude, insert, or reorder pending transactions for private gain. We specify and analyze the Themis Consensus Extension v1, first published by Mangata in 2021. The design separates value extraction by reordering (VER) from value extraction by denial (VED). For VER, block construction and execution occur across consecutive producers: one producer commits a transaction set, and the next derives a publicly verifiable, deterministic, previously un- predictable seed and executes a seed-determined, dependency-preserving permutation. For selective VED, a user may encrypt a transaction for a designated builder and executor. The builder removes an outer layer and commits the opaque inner ciphertext; the executor reveals and executes the plaintext only after commitment. Under selfish but non-colluding validators, an adversary below the underlying consensus fault threshold, secure cryptography, and accountable role performance, the construction limits unilateral post-commit ordering control and hides transaction intent from relays and the builder. It does not provide send-order or receive-order fairness, complete censorship resistance, resistance to builder-executor collusion, or per-transaction price guarantees. We analyze probabilistic extraction, spam, dependent transactions, decryption liveness, session boundaries, total denial, and threshold coalitions. We also document the initial Aura-based Substrate implementation and its subsequent transition to a BABE-based sr25519/VRF seed path, together with delayed execution, Fisher-Yates shuffling, and Xoshiro256++. The result preserves the original proposal while narrowing its claims to explicit assumptions.
