Blockchain technology is widely used in various fields due to its ability to provide decentralization and trustless security. This is a fundamental understanding held by many advocates, but it is misunderstood, leading participants to fail to recognize the limitations of the security that blockchain can provide. Among all current network attacks, Denial of Service (DoS) attacks pose significant threats due to their ease of execution and destructive potential. This paper, based on the blockchain architecture hierarchy, categorizes and organizes existing DoS attacks, with a focus on explaining the principles and methods of contract layer and consensus layer DoS attacks. Furthermore, this paper comprehensively analyzes and compares commonly used detection methods and defense technologies, which will contribute to strengthening the security and stability of blockchain systems and promoting further innovation and application of blockchain systems.

翻译：区块链技术因其能够提供去中心化和无需信任的安全性而在各个领域得到广泛应用。这是许多支持者的基本认知，但这种理解存在误区，导致参与者未能认识到区块链所能提供的安全性的局限性。在当前所有网络攻击中，拒绝服务攻击因其易于执行和破坏潜力巨大而构成重大威胁。本文基于区块链架构层次，对现有的DoS攻击进行了分类和梳理，重点阐述了合约层和共识层DoS攻击的原理与方法。此外，本文全面分析和比较了常用的检测方法与防御技术，这将有助于加强区块链系统的安全性与稳定性，并促进区块链系统的进一步创新与应用。