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：工作量证明区块链已作为开放环境（如互联网）中一种稳健且有效的共识机制而兴起，催生了众多加密货币平台的广泛部署及大量投资。然而，当前工作量证明的实现主要侧重于验证获胜随机数的发现。鉴于区块链网络庞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难题的理念变得引人注目。本研究对替代任务类别的先决条件进行了全面分析，并依据这些要求审视了现有文献中提出的设计方案。我们提炼了相关技术，并填补了当前最先进水平中的空白，为共识机制超越传统工作量证明的演进提供了宝贵见解。