A Survey on Proof of Sequential Work: Development, Security Analysis, and Application Prospects

TL;DR

This paper reviews proof of sequential work, a cryptographic method for verifying time-based computation, and its potential uses in decentralized systems and security.

Contribution

The paper provides a comprehensive survey of PoSW's development, security, and applications, with a focus on verifiable delay functions.

Findings

PoSW has significant potential in time-stamping and decentralized systems.

Verifiable delay functions are a key special case of PoSW with growing research interest.

The paper identifies potential attacks and evolutionary trends in PoSW.

Abstract

Proof of sequential work (PoSW), as an emerging cryptographic primitive, is designed to provide a verifiable method for proving that a computational process has incurred a real and continuous expenditure of time. This characteristic demonstrates its significant application potential in decentralized systems, time-stamping services, and trusted computing. This paper systematically reviews and discusses the developmental trajectory, typical variants, potential attacks, and diverse applications of PoSW. Concurrently, it places a special emphasis on analyzing the evolutionary path and application scenarios of its important special case—the verifiable delay function (VDF) aiming to provide a comprehensive reference for research and practice in related fields.

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