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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。
In the history of cryptography, data encryption standard DES is a very important symmetric cryptography algorithm proposed in the seventies of the last century. The algebraic immunity of Boolean functions is an important index of algebraic attacks against stream ciphers proposed in 2003 . S-box is the only non-linear part of DES. From the point of view of Boolean functions, we study the cryptographic properties such as algebraic immunity and non-linearity of 32 Boolean functions constructed by eight S-boxes of DES. These functions are all six variables Boolean function. The computational results in this paper show that the algebraic immunity of all 32 Boolean functions has reached its theoretical maximum of 3.