Cryptoeconomic Security for Data Availability Committees

TL;DR

This paper introduces a cryptoeconomic protocol for data availability committees in Layer 2 blockchain systems, ensuring security without trusting the DACs through incentives and game-theoretic analysis.

Contribution

It proposes a novel cryptoeconomic DAC protocol that aligns incentives to prevent adversarial behavior, achieving optimal security guarantees.

Findings

Protocol guarantees security with highest probability under assumptions

Provides a game-theoretic analysis of rational DAC nodes and clients

Ensures data availability without trusting DACs through economic incentives

Abstract

Layer 2 systems have received increasing attention due to their potential to scale the throughput of L1 blockchains. To avoid the cost of putting data on chain, these systems increasingly turn to off-chain data availability solutions such as data availability committees (DACs). However, placing trust on DACs conflicts with the goal of obtaining an L2 architecture whose security relies solely on the L1 chain. To eliminate such trust assumptions, we propose a DAC protocol that provides financial incentives to deter the DAC nodes from adversarial behavior such as withholding data upon request. We then analyze the interaction of rational DAC nodes and clients as a dynamic game, with a Byzantine adversary that can corrupt and bribe the participants. We also define a notion of optimality for the DAC protocols, inspired by fairness and economic feasibility. Our main result shows that our protocol is optimal and guarantees security with the highest possible probability under reasonable assumptions on the adversary.