Impossible Differential Cryptanalysis of Reduced-Round ARIA and Camellia  

作　　者：吴文玲 张文涛 冯登国 

机构地区：[1]State Key Laboratory of Information Security Institute of Software,Chinese Academy of Sciences [2]State Key Laboratory of Information Security Graduate University of Chinese Academy of Sciences

出　　处：《Journal of Computer Science & Technology》2007年第3期449-456,共8页计算机科学技术学报（英文版）

基　　金：This work is supported by the National Natural Science Foundation of China under Grant No.90604036;the National Grand Fundamental Research 973 Program of China under Grant No.2004CB318004.

摘　　要：This paper studies the security of the block ciphers ARIA and Camellia against impossible differential cryptanalysis. Our work improves the best impossible differential cryptanalysis of ARIA and Camellia known so far. The designers of ARIA expected no impossible differentials exist for 4-round ARIA. However, we found some nontrivial 4-round impossible differentials, which may lead to a possible attack on 6-round ARIA. Moreover, we found some nontrivial 8-round impossible differentials for Camellia, whereas only 7-round impossible differentials were previously known. By using the 8-round impossible differentials, we presented an attack on 12-round Camellia without FL/FL^-1 layers.This paper studies the security of the block ciphers ARIA and Camellia against impossible differential cryptanalysis. Our work improves the best impossible differential cryptanalysis of ARIA and Camellia known so far. The designers of ARIA expected no impossible differentials exist for 4-round ARIA. However, we found some nontrivial 4-round impossible differentials, which may lead to a possible attack on 6-round ARIA. Moreover, we found some nontrivial 8-round impossible differentials for Camellia, whereas only 7-round impossible differentials were previously known. By using the 8-round impossible differentials, we presented an attack on 12-round Camellia without FL/FL^-1 layers.

关 键 词：block cipher ARIA CAMELLIA data complexity time complexity impossible differential cryptanalysis 

分 类 号：TP393.08[自动化与计算机技术—计算机应用技术]