高级加密标准的差分特征

Differential Characters of the Advanced Encryption Standard

通过对美国高级加密标准(AES)特点的分析,引入差分特征输入差分活性盒分布图的概念,给出了一种计算AES差分特征的方法,从而使得计算AES的多轮差分特征成为可能.并且给出了用这种方法获得的AES3～12轮高概率的差分特征,其中3、4轮差分特征的概率与理论值相符.到目前为止,本文给出的3～12轮差分特征概率是所有已知的AES的多轮差分特征概率中最大的;并且首次给出了AESr(3≤r≤12)轮最大概率差分特征的差分活性盒数目范围及概率上界.

Searching differential characters with high probability is an effective way to attack block cipher. To find a practical and effective method to attack American advanced encvyption standard(AES) becomes a new challenge in the field of block cipher. Unfortunately, research results show that there is no effective way to attack AES, nor even compute many rounds differential or linear characters of AES. We give a new method to compute differential characters of AES by analyzing characteristic of AES and make it possible to compute many rounds differential of AES. In this paper we introduce our results about 3～12 rounds differential characters of AES in details, where those of 3～4 rounds are the best. By now they have the biggest probability among all known differential characters of AES, and we also give the range of active boxes of many rounds differential characters of AES with the highest probability and their better upper bound.