Proof-of-Work (PoW) blockchains have emerged as a robust and effective consensus mechanism in open environments like the Internet, leading to widespread deployment with numerous cryptocurrency platforms and substantial investments. However, the current PoW implementation primarily focuses on validating the discovery of a winning nonce. Exploring the notion of replacing cryptographic puzzles with useful computing tasks becomes compelling, given the substantial computational capacity of blockchain networks and the global pursuit of a more sustainable IT infrastructure. In this study, we conduct a comprehensive analysis of the prerequisites for alternative classes of tasks, examining proposed designs from existing literature in light of these requirements. We distill pertinent techniques and address gaps in the current state-of-the-art, providing valuable insights into the evolution of consensus mechanisms beyond traditional PoW.

翻译：工作量证明（PoW）区块链已发展成为互联网等开放环境中一种稳健有效的共识机制，催生了众多加密货币平台及大量投资，得以广泛部署。然而，当前PoW实现主要聚焦于验证获胜随机数的发现。考虑到区块链网络巨大的计算能力以及全球对更可持续IT基础设施的追求，探索用有用计算任务替代密码谜题的概念变得颇具吸引力。本研究全面分析了替代任务类别的先决条件，并根据这些要求审视了现有文献中的设计方案。我们提炼了相关技术，并填补了当前研究现状中的空白，为超越传统PoW的共识机制演化提供了宝贵见解。