量子攻击模型下分组密码分析方法组合优化研究

The security analysis of block ciphers has always been a hot research of cryptography. With the development of quantum technology, some research works have found out that some modes of block cipher and the buliding structure of block cipher could be broken under quantum technology. However, there are few analyses on the algorithms of block ciphers. It is difficult to extend these quantum attacks to the other block ciphers. Because the attacker cannot explore the properties suitable for quantum algorithms from these block ciphers based on iterative design. How to analyze and evaluate the security strength of block cipher against quantum attacks has become a major challenge in cryptography research. In order to solve this problem, we will adopt the following steps. Firstly, we focus on two key issues: 1. the modular disassembly and reconstruction of quantum algorithm and 2. the efficiency optimization of quantum algorithms under resource constraints, which are based on quantum algorithm and traditional analysis methods. Secondly, we try to propose some new technologies such as integral partition of iterative block cipher algorithm, dynamic recombination of quantum algorithm, time storage compromise technology and quantum transformation of traditional analytical methods. Based on the security analysis of block cipher algorithm, we try to construct a quantum algorithm analysis model so as to optimize the analysis results of existing quantum algorithms. This study not only provides a theoretical basis for improving the security analysis of block cipher algorithm in quantum environment, but also provides a reference for the design of new block cipher algorithm.

分组密码算法的安全性分析一直是密码学的研究热点。随着量子技术的发展，有研究发现分组密码的部分工作模式和整体结构存在量子攻击的弱点。然而，由于分组密码算法大多采用迭代式设计，难以满足单一量子算法的使用限制，使得量子算法难以简单扩展应用，导致在算法层次的成果较少。因此，如何分析评估分组密码算法抵抗量子攻击的安全强度，已经成为密码研究的一大挑战。为此，本项目将以量子算法和传统分析方法为理论基础，主要研究量子算法的模块化拆解与重构、以及资源受限条件下量子算法的效率优化这两个关键问题，重点突破迭代式分组密码算法的结构化分割、量子算法与时间存储折中技术的动态重组、以及传统分析方法的量子转化等关键技术，并以分组密码算法的安全分析为核心，构建量子算法分析模型，优化现有分组密码算法的量子分析结果。本研究不但为改进量子环境下分组密码算法的安全性分析提供了理论依据，而且为新式分组密码算法的设计提供了借鉴与参考。

分组密码算法是密码学的研究热点，并作为一种重要的底层加密技术应用于各个信息系统。本项目以量子技术为基础，通过分析分组密码的性质特点，得到了如下结果：1）在量子攻击模型的优化与扩展模型下，项目组通过将Simon算法的周期性质与生日攻击思想相结合，提出了对于FEISTEL等结构的新型传统密钥恢复攻击；此外，项目组还通过将BHT碰撞算法与差分攻击相结合，对EM结构构造了高效的密钥恢复攻击。2）在资源受限条件下，提出了新型量子多碰撞算法。对比Grover量子搜索算法，新型攻击方法在存储受限环境下可以实现至少5%的效率提升；3）项目组对AES算法提出了一种存储优先的量子线路实现方案，并将上述技术进一步应用于SM3、SM4等密码算法；4）项目组还对一系列有限域的性质进行了分析，这些上述分析结果可以应用于改进S盒等操作的实现代价。