【作者】 赵剑锋；

【导师】 王兴元；

【作者基本信息】 大连理工大学 ， 计算机应用技术， 2010， 硕士

【摘要】 混沌密码学是非线性科学和信息科学的交叉学科,近些年来得到了众多学者的广泛研究。本文对基于混沌理论的密码技术进行了研究,详细设计和分析了几种混沌密码系统,主要内容如下：(1)基于混沌的对称密码系统的设计。分别设计了一种基于多个一维映射的混沌密码系统和一种混沌图像加密系统。这两种系统都采用了多个混沌映射,通过迭代不同的混沌映射来生成伪随机序列。数字化的混沌伪随机序列被用于实际的加密和解密操作。此外,简要介绍了另外两种密码系统的设计。(2)基于混沌的对称密码系统的分析。分别对两种对称混沌密码系统进行了密码分析。指出了这两种密码系统存在的缺陷,并且成功地实施了选择明文攻击。最后,提出了改进上述密码系统安全性的一些措施。(3)基于混沌的单向散列函数的研究。对一种基于混沌神经网络的并行带密钥单向散列函数进行了密码分析,指出该散列函数的弱密钥,并且成功地实施了伪造攻击。最后,对该单向散列函数进行了改进。(4)基于混沌的公开密钥密码的研究。提出了一种改进的基于Chebyshev混沌映射的公开密钥加密算法,在此基础上,设计了一个可以在网络中使用的密钥协商协议。该协议克服了之前提出的基于混沌的密钥协商协议的一些缺陷,具有较高的安全性。更多还原

【Abstract】 Chaotic cryptography is an interdisciplinary subject of nonlinear science and information science, which has been widely studied by many scholars. In this thesis, the cryptographic technique based on chaos theory has been studied, and several chaotic cryptosystems have been designed and analyzed. The main contents are as follows:(1) Design of symmetric cryptosystems based on chaos. A chaotic cryptosystem based on multiple one dimensional maps and a chaotic image encryption system are designed respectively. Both systems adopt multiple chaotic maps and the pseudorandom sequences are generated by iterating these chaotic maps. The digitized chaotic pseudorandom sequences are used for encryption and decryption operations. Besides, two other chaotic cryptosystems are introduced briefly.(2) Cryptanalysis of symmetric cryptosystems based on chaos. Cryptanalysis of two different kinds of symmetric chaotic cryptosystems is presented. The drawbacks of the two chaotic cryptosystems are pointed out respectively, and chosen plaintext attacks are carried out successfully. Last, some remedial improvements are demonstrated to enhance the security of the cryptosystems.(3) Study of one-way hash function based on chaos. Cryptanalysis of a parallel keyed hash function based on chaotic neural network is presented in detail. Weak keys of the hash function are pointed out, and forgery attacks are carried out successfully. Then, some remedial improvements are also provided.(4) Study of public key cipher based on chaos. An improved public key encryption algorithm based on Chebyshev chaotic map is proposed. Then, based on this algorithm, a key agreement protocol that could be used in computer network is proposed. This protocol overcomes the drawbacks of several previously proposed chaotic key agreement protocols, so it is effective and secure.更多还原