A New Method for Searching Impossible Differentials of Block Cipher
Automatic search of impossible differentials for block ciphers is useful for impossible differential cryptanalysis.This paper introduces a tool to search impossible differentials.The idea of this tool is an extension of Wu”s idea ”1”.The extension is that we designed a complete new representation of difference values with corresponding algorithm.Our tool has 3 steps; one of them is an optional step which can be omitted according to the real situation.Without this step,the time complexity of our algorithm is O(mr4l4 ),where m is the upper bound of the number of possible difference values,r is the number of rounds and l is the number of words in the plaintext.With the optional step,our algorithm need O(m2r5l5 ) time complexity,and the space complexity is O(r2l2 ).We apply our tool to find impossible differentials for block ciphers,including AES,ARIA,LBlock,MIBS,Piccolo,Twine,and Camellia without FL and FL-1 layers.Among them,we get all impossible differentials best known so far.For MIBS and Twine,we found new results with the same number of rounds as the best known results ”1””5”.Our method can find more impossible differentials that would be missed by previous methods.
Impossible differentials Differential cryptanalysis Block cipher
Hui-Huang ZHENG Zhe-Yi PAN Wei-Jia XUE Xue-Jia LAI
Shanghai Jiao Tong University,China
国内会议
杭州
英文
1-12
2014-10-18（万方平台首次上网日期，不代表论文的发表时间）