毕业论文：《对AES算法的线性分析》.docVIP

l 摘要 密码学是有着奇妙而悠久的历史的一门科学。自从1976年Diffie和Hellman两人共同提出公钥密码体制概念以来，公钥密码体系便蓬勃发展起来,几乎成为现在密码理论研究的主流。但是公钥密码体系所面临的高运算量的问题，使它在实际应用中受到限制。因此在密码学理论研究的领域中，单钥密码体系仍然是一个值得研究的方向。数据加密标准AES就是一种在传输和存储数据中保护计算机数据的分组密码算法。我们将详细讨论AES线性分析的方法，再此之前我们引入了简化16位AES，学习AES线性分析方法，并为AES线性分析提供理论依据。分析证明简化AES是可以完全破解的，并说明了一定的问题，那就是在密钥和分组长度较短时，AES这种加密结构是不安全的。就128位密钥AES我们通过程序进行了分析，S盒输入输出最高的概率太低，只有0.56。方程组过于庞大，且求解困难。事实证明这种方法在128位AES上得到不了理想的结果。无法取得满意的线性逼近表达式。 【关键词】:分组密码;线性密码分析;密钥;概率;AES  Abstract Cryptography is wonderful science and it has a long. Since Diffie and Hellman co-sponsored the concept of public key cryptography in 1976, public key cryptography system has thrived, it nearly become the mainstream of the theory of the Cryptography. However, public key cryptography system is faced the problem of high computational complexity, it is limited in practical application. Therefore, in the field of theoretical research of cryptography, the single-key cryptography system is still a valuable research direction. Data Encryption Standard AES is block cipher which protects the computer data in the transfer and store data. We will discuss the linear analysis method of AES in detail, before this method, we introduce a simplified 16-bit AES, and learn AES linear method, and provide the theoretical basis of linear analysis of AES. Analyse and provide that simplified AES can be completely break, and shows some problems, it is that AES encryption structure is unsafe, when the key and the packet length is short. we analyse the AES 128-bit key on procedure, the input and output the highest probability of the S box is too low, it is only 0.56. Equations is too large, and the solution is too difficult. This approach has proven 128-bit AES can not get the desired results. We can’t achieve a satisfactory expression of Linear approximation. 【Key words】: block cipher; linear cryptanalysis; keys; probability; AES  目录 TOC \o 1-3 \u 摘要 h I Abstract h II 1. 引言 h 1 1.1 研究动机 h 1 1.2 论文组织架构 h 2 1.3 论文主要成果 h