Let Leaders Play Games: Improving Timing in Leader-based Consensus

2026-02-11

AI Summary

This work addresses the problem of “time gaming” in leader-based blockchain consensus, where elected leaders delay block proposal to extract greater maximal extractable value (MEV), thereby compromising network efficiency and fairness. The paper introduces the first formal model of this behavior as a “delay game” and proposes 2-Prop, an incentive-compatible dual-proposer mechanism that elects two proposers per round and dynamically allocates rewards based on block propagation speed to incentivize early block release. Theoretical analysis shows that in homogeneous networks, immediate block proposal constitutes a Nash equilibrium; in heterogeneous networks, fast nodes only have an incentive to delay if their counterpart propagates blocks extremely slowly. The proposed mechanism effectively suppresses time gaming and significantly enhances both consensus efficiency and fairness.

Technology Category

• Multiagent Systems: Mechanism Design
• Game Theory and Economic Paradigms: Mechanism Design
• Search and Optimization: Distributed Search

Application Category

• Security and Privacy: Blockchains and distributed ledgers
• Economics, Online Markets and Human Computation: Incentives in network design for Web infrastructures and ecosystems
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

Abstract

Propagation latency is inherent to any distributed network, including blockchains. Typically, blockchain protocols provide a timing buffer for block propagation across the network. In leader-based blockchains, the leader -- block proposer -- is known in advance for each slot. A fast (or low-latency) proposer may delay the block proposal in anticipation of more rewards from the transactions that would otherwise be included in the subsequent block. Deploying such a strategy by manipulating the timing is known as timing games. It increases the risk of missed blocks due to reduced time for other nodes to vote on the block, affecting the overall efficiency of the blockchain. Moreover, proposers who play timing games essentially appropriate MEV (additional rewards over transaction fees and the block reward) that would otherwise accrue to the next block, making it unfair to subsequent block proposers. We propose a double-block proposal mechanism, 2-Prop, to curtail timing games. 2-Prop selects two proposers per slot to propose blocks and confirms one of them. We design a reward-sharing policy for proposers based on how quickly their blocks propagate to avoid strategic deviations. In the induced game, which we call the Latency Game, we show that it is a Nash Equilibrium for the proposers to propose the block without delay under homogeneous network settings. Under heterogeneous network settings, we study many configurations, and our analysis shows that a faster proposer would prefer not to delay unless the other proposer is extremely slow. Thus, we show the efficacy of 2-Prop in mitigating the effect of timing games.

Problem

• timing games
• blockchain consensus
• propagation latency
• MEV
• leader-based protocols

Innovation

• timing games
• blockchain consensus
• double-block proposal
• MEV
• Latency Game