高级加密标准AES的实现研究

【作者】 赵勇；

【导师】 周亮；

【作者基本信息】 电子科技大学 ， 密码学， 2004， 硕士

【摘要】 2002年5月，根据Rijndael算法改编而成的高级加密标准(AES)正式生效。本文分析了AES算法的设计原理与安全性，探讨了AES算法中关键性的求逆问题，在PC机和DSP上实现了AES算法。安全性是设计密码算法考虑的首要问题。本文从分析Rijndael算法的结构出发，分析了S盒的代数特性、P层的扩散性能，以及密钥加层的混乱和扩散性能，从而证明了AES算法能抵抗差分密码攻击、线性密码攻击和其它已知密码攻击。AES算法不存在陷门。多项式求逆是影响算法执行速度的重要因素。本文运用有限域、线性代数和矩阵理论，论证了逆多项式和逆仿射的存在性，并且应用查表法简捷地实现了中元素的求逆和逆仿射变换；设计了一个易于在在计算机上实现的算法，来求形如的多项式模时的逆元，该多项式的系数在上。 AES算法优良的适应性使其易于在各种平台上实现。本文提出了Rijndael算法基于32位的编程方案，并用C语言实现了方案，其中的主要操作为查表、异或和移位操作。该算法很容易在各种32位平台上实现，且可以获得较高的速度。AES算法在DSP上有着良好的表现。本文阐述了C语言与汇编语言混合编程方法和接口规范，实现了AES算法的混合编程；应用编译器的优化选项和其它优化技巧优化了算法，使算法具有较高的加密速度；提出了AES算法的优化原则。更多还原

【Abstract】 The Advanced Encryption Standard (AES) based on the Rijndael algorithm has become effective on May 2002. This thesis analysis the design principles and security and studies the critical algorithm of element inverse in the AES. Also the thesis presents an implementation for AES upon the DSP and PC platforms.Security is the primitive problem in cryptographic design. First of all, the structure of the Rijndael algorithm is analyzed. Then the algebra property of S–box, the diffusion of the P layer and the confusion is analyzed. According to the analysis, a conclusion is educed that the AES algorithm has the ability of resisting against differential cryptanalysis and linear cryptanalysis and other all known attacks. The Rijndael algorithm has no trapdoor.The inverse transformation of polynomial is the key factor affected the speed of the algorithm. The inverse polynomial and the invertible affine transformation exist by the finite field, linear algebra and matrix theory. The invertible affine transformation and the inversion in are easily realized by using lookup table. An algorithm can be used to get the inverse element of modulo . The flexibility of the AES algorithm makes it possible used on different platforms. The Rijndael algorithm based on API 32 is proposed in this paper and it is realized in C. The main operators are lookup table and XOR and shift. The algorithm is very easily implemented on Win32 with high speed.The AES algorithm has pretty good performance in DSP. The program method and interface criterion and the implementation of mix program of AES algorithm are expatiated in this paper. Also the algorithm is optimized with compiler optimal sets and others methods that make the algorithm achieve faster speed of encryption. The optimization criterions of AES algorithm are suggested as well.更多还原