【摘要】 提出了用于分组密码分析的分区线性分析法.以SAFER++为例,通过基础模块的密码特性分析,建立密码分析的线性逼近式.该逼近式的特点是把密钥的比特位分区出现在逼近式的任选项中,这样不仅可以攻击密钥的所有比特位,而且大大降低了攻击的复杂度,并从理论上证明了逼近式的优势与任何子密钥的最低有效位无关.迄今为止有关文献都认为相关子密钥最低有效位等于0是逼近优势非零的前提条件.更多还原

【Abstract】 A cryptanalysis method called partition linear cryptanalysis for block ciphers is presented in this paper.With the case of SAFER++ as an example,the special linear approximations were obtained by analyzing the basic modules.In thses approximations,the bits of a master key were divided into several parts and could be arbitrarily selected to attack SAFER++.It is possible that all of the key bits can be determined and the attack complexity is greatly reduced at the same time.It is also theoretically proved that the bias of linear approximations have no relation with the least significant bit of every subkey.This is a new conclusion.Many papers so far have reported that the least significant bit of correlative subkeys should be 0 for the bias holding.更多还原