标题： 基于密码学的区块链安全：综述 显示英文标题

标题： Blockchain security based on cryptography: a review

摘要： 作为一种通过结合密码学、P2P网络、共识机制和创新合约技术构建的新兴服务框架，区块链由于其去中心化、不可篡改和交易可追溯性，已被广泛应用于数字金融、数据共享、信息溯源和电子证据保存。 然而，随着区块链技术复杂多变的应用场景以及区块链攻击技术的不断进步，区块链系统的安全性受到了严重威胁，极大地影响了区块链技术的发展和应用。 本文旨在从密码学的角度分析对区块链的攻击。 首先，从区块链中的密码学技术出发，介绍了哈希函数、数字签名等技术的原理及其在区块链中的作用。 然后，基于区块链的六层架构，分析了数据层、网络层、共识层、合约层、激励层和应用层的攻击，并提出了缓解或抵御这些攻击的方法。 其次，分析了51%攻击、双花攻击、重入攻击、重放攻击、Sybil攻击和时间戳篡改攻击的攻击原理，并为这六种攻击设计了缓解或防御方案。 最后，总结了区块链技术需要解决的核心问题，并展望了区块链安全技术的未来发展。 显示英文摘要

摘要： As an emerging service framework built by combining cryptography, P2P network, consensus mechanism and innovative contract technology, blockchain has been widely used in digital finance, data sharing, message traceability and electronic evidence preservation because of its decentralised, non-tamperable and transaction traceability. However, with the complex and changeable application scenarios of blockchain technology and the continuous enhancement of blockchain attack technology, the security of the blockchain system has been seriously threatened, dramatically affecting the development and application of blockchain technology. This paper aims to analyse the attacks on blockchain from the perspective of cryptography. Firstly, from the cryptography technology in the blockchain, the principle of hash functions, digital signatures, and other technologies, as well as their role in the blockchain, are introduced. Then, based on the six-layer architecture of the blockchain, the attacks on the data layer, the network layer, the consensus layer, the contract layer, the incentive layer and the application layer are analysed, and the methods to mitigate or resist the attacks are proposed. Secondly, the attack principles of 51% attack, Double-Spending attack, Reentrancy attack, Replay attack, Sybil attack and Timestamp Tampering attack were analysed, and the mitigation or defence solutions for these six attacks were designed. Finally, the core problems to be solved in blockchain technology are summarised, and the future development of blockchain security technology is projected.