【摘要】 在密码学的历史上,数据加密标准DES是上个世纪七十年代提出的一个非常重要的对称密码算法,布尔函数的代数免疫度是2003年提出来的抵抗流密码的代数攻击的一个重要指标。S盒是DES中唯一的非线性部分,从布尔函数的观点,研究DES的八个S盒所构造的32布尔函数的代数免疫度和非线性度等密码学性质,这些函数都是六个变量的布尔函数。文中的计算结果表明,所有32个布尔函数的代数免疫度都达到了其理论上的最大值3。更多还原

【Abstract】 In the history of cryptography,DES(Data Encryption Standard),developed by IBM around 1974 and adopted as a national standard in 1977,is one of the most important symmetric encryption algorithm.However,the algebraic immunity was proposed in 2003 to resist the algebraic attack on stream ciphers.The eight S-boxes are the only nonlinear part of the algorithm.From the viewpoint of Boolean functions,the algebraic immunities and the nonlinearities of the 32 Boolean functions generated from DES’s eight S-boxes are studied,and these 32 functions are Boolean functions of six variables.Experiments result shows that the algebraic immunities of all the 32 Boolean functions could reach their theoretical maximal value 3.更多还原