# 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.

## Key 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.