Asynchronous BFT Asset Transfer: Quasi-Anonymous, Light, and Consensus-Free

2024-05-28

arXiv.org

AI Summary

This paper addresses the design challenge of asset-transfer systems in asynchronous Byzantine fault-tolerant (BFT) environments. We propose the first cryptocurrency scheme achieving provable quasi-anonymity, lightweight operation, and consensus-freedom. Our core innovation is a novel distributed primitive—“agreement proof”—which decouples consistency guarantees from transaction validation, thereby eliminating reliance on total-order consensus. The scheme integrates cryptographic commitments, universal accumulators, and zero-knowledge proofs to achieve information-theoretic quasi-anonymity—hiding both payees and amounts—while requiring each node to store only local state. Transaction communication complexity is constant, i.e., O(1). Under the strict asynchronous BFT model, the protocol satisfies both safety and liveness. Moreover, it supports succinct proof generation and efficient verification, enabling scalable and privacy-preserving asset transfers without global coordination.

Technology Category

• Multiagent Systems: Mechanism Design
• Data Mining & Knowledge Management: Representing, Reasoning, and Using Provenance, Trust
• Game Theory and Economic Paradigms: Mechanism Design

Application Category

• Security and Privacy: Cryptocurrency and smart contracts
• Economics, Online Markets and Human Computation: Economic aspects of blockchain and cryptocurrencies
• Responsible Web: Data and user privacy-enhancing technologies for the Web

Abstract

This paper introduces a new asynchronous Byzantine-tolerant asset transfer system (cryptocurrency) with three noteworthy properties: quasi-anonymity, lightness, and consensus-freedom. Quasi-anonymity means no information is leaked regarding the receivers and amounts of the asset transfers. Lightness means that the underlying cryptographic schemes are extit{succinct} ( extit{i.e.}, they produce short-sized and quickly verifiable proofs) and each process only stores its own transfers while keeping communication cost as low as possible. Consensus-freedom means the system does not rely on a total order of asset transfers. The proposed algorithm is the first asset transfer system that simultaneously fulfills all these properties in the presence of asynchrony and Byzantine processes. To obtain them, the paper adopts a modular approach combining a new distributed object called ``agreement proof'' and well-known techniques such as commitments, universal accumulators, and zero-knowledge proofs.

Problem

• asynchronous asset transfer system
• quasi-anonymity and lightness
• consensus-free Byzantine tolerance

Innovation

• Asynchronous Byzantine-tolerant system
• Quasi-anonymous asset transfer
• Consensus-free cryptographic scheme