Multiple Proposer Transaction Fee Mechanism Design: Robust Incentives Against Censorship and Bribery

TL;DR

This paper designs a transaction fee mechanism for multiple proposers in blockchains to ensure censorship resistance and prevent bribery, addressing gaps in existing protocols like FOCIL and aligning with incentive compatibility principles.

Contribution

It introduces a concrete payment mechanism for FOCIL that incentivizes censorship resistance under bribery attacks and analyzes incentive compatibility in complex protocol scenarios.

Findings

Proposes a TFM that resists bribery and enforces censorship resistance.

Analyzes incentive compatibility in multi-phase and uncertain-party protocols.

Provides a generalizable framework for incentivizing multiple proposers.

Abstract

Censorship resistance is one of the core value proposition of blockchains. A recurring design pattern aimed at providing censorship resistance is enabling multiple proposers to contribute inputs into block construction. Notably, Fork-Choice Enforced Inclusion Lists (FOCIL) is proposed to be included in Ethereum. However, the current proposal relies on altruistic behavior, without a Transaction Fee Mechanism (TFM). This study aims to address this gap by exploring how multiple proposers should be rewarded to incentivize censorship resistance. The main contribution of this work is the identification of TFMs that ensure censorship resistance under bribery attacks, while also satisfying the incentive compatibility properties of EIP-1559. We provide a concrete payment mechanism for FOCIL, along with generalizable contributions to the literature by analyzing 1) incentive compatibility of TFMs in the presence of a bribing adversary, 2) TFMs in protocols with multiple phases of transaction inclusion, and 3) TFMs of protocols in which parties are uncertain about the behavior and the possible bribe of others.