Block space on the blockchain is scarce and must be allocated efficiently through block building. However, Ethereum's current block-building ecosystem, MEV-Boost, has become highly centralized due to integration, which distorts competition, reduces blockspace efficiency, and obscures MEV flow transparency. To guarantee equitability and economic efficiency in block building, we propose $\mathrm{Boost+}$, a system that decouples the process into collecting and ordering transactions, and ensures equal access to all collected transactions. The core of $\mathrm{Boost+}$ is the mechanism $\mathit{M}_{\mathrm{Boost+}}$, built around a default algorithm. $\mathit{M}_{\mathrm{Boost+}}$ aligns incentives for both searchers (intermediaries that generate or route transactions) and builders: Truthful bidding is a dominant strategy for all builders. For searchers, truthful reporting is dominant whenever the default algorithm dominates competing builders, and it remains dominant for all conflict-free transactions, even when builders may win. We further show that even if a searcher can technically integrate with a builder, non-integration combined with truthful bidding still dominates any deviation for conflict-free transactions. We also implement a concrete default algorithm informed by empirical analysis of real-world transactions and evaluate its efficacy using historical transaction data.

翻译：区块链上的区块空间是稀缺资源，必须通过区块构建进行高效分配。然而，以太坊当前的区块构建生态系统MEV-Boost因集成化已变得高度中心化，这扭曲了竞争、降低了区块空间效率，并模糊了MEV流动的透明度。为确保区块构建的公平性与经济效率，我们提出$\mathrm{Boost+}$系统，该系统将区块构建过程解耦为交易收集与排序两个阶段，并确保所有收集到的交易具有平等访问权。$\mathrm{Boost+}$的核心是围绕默认算法构建的机制$\mathit{M}_{\mathrm{Boost+}}$。该机制使搜索者（生成或路由交易的中介）与构建者的激励保持一致：诚实出价是所有构建者的占优策略。对于搜索者而言，只要默认算法优于竞争构建者，诚实报告即为占优策略；且对于所有无冲突交易，即使构建者可能胜出，诚实报告仍保持占优性。我们进一步证明，即使搜索者技术上可与构建者集成，对于无冲突交易，非集成结合诚实出价仍优于任何偏离策略。我们还基于对真实交易数据的实证分析，实现了一个具体的默认算法，并利用历史交易数据评估了其有效性。