Abstract: Using the advantage of simulate annealing algorithms, this paper presents an evolutionary searching algorithm to search the best linear approximation of DES, analyzes its properties and gives the simulate experiment results. This method is applicable to block ciphers with feistel constructures, and it would still be very applicable when the length of block increases.

Key words: DES, Linear cryptanalysis, Best linear approximation, Simulate annealing algorithms

摘要： 模拟退火算法是基于金属退火机理而建立起来的一种全局最优化方法，它能够以随机搜索技术从概率意义上找出目标函数的全局最小点。该文利用模拟退火算法的优越性，给出了对DES最佳线性逼近的进化式搜索算法算法，分析了算法的有关性质，给出了模拟实验结果。该算法适用于一般Feistel结构的分组密码，且在分组长度增加时仍具有较强的适用性。

关键词: DES, 线性密码分析, 最佳线性逼近, 模拟退火算法