[论文解读] SoK: Blockchain Decentralization

Luyao Zhang, Xinshi Ma+1 more|arXiv (Cornell University)|May 9, 2022

Blockchain Technology Applications and Security被引用 32

一句话总结

本综述定义了区块链去中心化的五大方面的分类法，提出基于熵的去中心化指数，比较替代度量，并在使用开源代码的DeFi数据上展示描述性、预测性和因果方法。

ABSTRACT

Blockchain introduces decentralized trust in peer-to-peer networks, advancing security and democratizing systems. Yet, a unified definition for decentralization remains elusive. Our Systematization of Knowledge (SoK) seeks to bridge this gap, emphasizing quantification and methodological coherence. We've formulated a taxonomy defining blockchain decentralization across five facets: consensus, network, governance, wealth, and transaction. Despite the prevalent focus on consensus decentralization, our novel index, based on Shannon entropy, provides comprehensive insights. Moreover, we delve into alternative metrics like the Gini and Nakamoto Coefficients and the Herfindahl-Hirschman Index (HHI), supplemented by an open-source Python tool on GitHub. In terms of methodology, blockchain research has often bypassed stringent scientific methods. By employing descriptive, predictive, and causal methods, our study showcases the potential of structured research in blockchain. Descriptively, we observe a trend of converging decentralization levels over time. Examining DeFi platforms reveals exchange and lending applications as more decentralized than their payment and derivatives counterparts. Predictively, there's a notable correlation between Ether's returns and transaction decentralization in Ether-backed stablecoins. Causally, Ethereum's transition to the EIP-1559 transaction fee model has a profound impact on DeFi transaction decentralization. To conclude, our work outlines directions for blockchain research, emphasizing the delicate balance among decentralization facets, fostering long-term decentralization, and the ties between decentralization, security, privacy, and efficiency. We end by spotlighting challenges in grasping blockchain decentralization intricacies.

研究动机与目标

• 在共识、网络、财富、治理和交易五个方面建立区块链去中心化的分类法。
• 提出一个基于香农熵、适用于区块链各方面的可解释去中心化指数。
• 将描述性、预测性和因果推断方法应用于公开的DeFi数据，以研究去中心化动态。

提出的方法

• 开发一个将去中心化各方面与区块链层（基础设施、激励、应用）联系起来的分类法。
• 通过对交易价值分布的香农熵进行变换来定义去中心化指数 H(V)。
• 分析该指数的性质并给出引理，进行仿真实验以说明交易数量 N 与分布如何影响 H。
• 考虑替代度量，如基尼系数、中本聪系数和赫芬达尔-赫希曼指数（HHI）。
• 提供用于在 GitHub 上计算所提出的指数及替代指标的开源 Python 代码。

实验结果

研究问题

• RQ1 RQ1：区块链去中心化的哪些方面，以及文献如何界定和衡量它们？
• RQ2 RQ2：我们能否提出一个可解释的去中心化指数来衡量和量化跨各方面的去中心化？
• RQ3 RQ3：如何将去中心化指数应用于使用描述性、预测性和因果方法的实证研究？

主要发现

• 在五个方面（共识、网络、治理、财富和交易）上的区块链去中心化分类法。
• 通过对香农熵进行变换得到的新去中心化指数，交易分布越均匀越高，且具有直观解释。
• 实证应用显示DeFi应用中的去中心化存在差异，描述性趋势趋同，EIP-1559 对去中心化具有因果影响；预测分析将以太币回报与以太币支持的稳定币的去中心化相关联。