高级加密标准AES-192的7轮不可能差分分析

Impossible differential attacks on 7-round AES-192

结合密钥扩展算法和划分子集的方法,提出7轮AES-192的不可能差分分析方法.首先估算猜测初始轮的错误密钥的最小概率;然后计算所需的明密文对的数量并选择明密文对,计算密文对的差分,猜测特殊的密钥字节对其进行不可能差分攻击.该攻击需要278选择明文,记忆存储空间为2129分组,以及约2155的7轮AES-192加密.与目前现有的结果相比,该攻击需要更少的选择明文数和较低的时间复杂度.

A method was proposed to recover the secret key for impossible differential cryptanalysis of 7-round AES-192 combined with classing subsets and exploiting weaknesses in their key schedule.The minimum probability of original round false key was guessed.Then,the number of plaintexts and ciphertexts and chose them was computed.By the difference of chosen ciphertexts,the specific keys for impossible differential cryptanalysis was guessed.This attack requires about 278 chosen plaintexts,demands 2129 words of memory,and performs 2155 7-round AES-192 encryptions.Compared with the available results,this cryptanalysis costs fewer chosen-plaintexts and lower computing complexity,and the number of chosen plaintexts and ciphertexts was easy to come true in theory.