Boost+: Equitable, Incentive-Compatible Block Building

TL;DR

Boost+ introduces a new block-building system that promotes fairness, transparency, and incentive compatibility by decoupling transaction collection and ordering, ensuring equal access and truthful bidding among participants.

Contribution

The paper proposes Boost+, a novel system with a default algorithm that aligns incentives and guarantees truthful reporting, addressing centralization and transparency issues in Ethereum's block building.

Findings

Boost+ achieves incentive compatibility for builders and searchers.

The default algorithm promotes truthful bidding and fair access.

Empirical evaluation shows improved efficiency and transparency.

Abstract

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.