Fairness Notions in DAG-based DLTs

TL;DR

The paper tackles fairness in DAG-based DLTs, motivated by fairness failures such as MEV and centralization in traditional blockchains. It systematically defines fairness notions across participants, consensus ordering, and component-level aspects, and surveys how these notions interact with DAG protocols, including weak links, tip selection, garbage collection, and rewards. It reviews existing DAG protocols (e.g., Aleph, Narwhal, Bullshark, SPECTRE, PHANTOM) and discusses cryptographic approaches to fairness such as commit-reveal, threshold encryption, and TEEs, outlining practical design trade-offs. The work provides informal definitions, links fairness to core DLT components, and proposes future research directions to develop cryptographic mechanisms that promote fairness while preserving scalability. The paper aims to provide a knowledge base and set of metrics to evaluate whether DAG-based DLTs can achieve more equitable designs suitable for wide adoption.

Abstract

This paper investigates the issue of fairness in Distributed Ledger Technology (DLT), specifically focusing on the shortcomings observed in current blockchain systems due to Miner Extractable Value (MEV) phenomena and systemic centralization. We explore the potential of Directed Acyclic Graphs (DAGs) as a solution to address or mitigate these fairness concerns. Our objective is to gain a comprehensive understanding of fairness in DAG-based DLTs by examining its different aspects and measurement metrics. We aim to establish a shared knowledge base that facilitates accurate fairness assessment and allows for an evaluation of whether DAG-based DLTs offer a more equitable design. We describe the various dimensions of fairness and conduct a comparative analysis to examine how they relate to different components of DLTs. This analysis serves as a catalyst for further research, encouraging the development of cryptographic systems that promote fairness.