Improved Higher Order Differential Attack and Its Application to Nyberg-Knudsen's Designed Block Cipher

Takeshi SHIMOYAMA  Shiho MORIAI  Toshinobu KANEKO  Shigeo TSUJII  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E82-A   No.9   pp.1971-1980
Publication Date: 1999/09/25
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: PAPER
Category: Information Security
block cipher,  higher order differential attack,  KN cipher,  algebraic equation,  

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Since the proposal of differential cryptanalysis and linear cryptanalysis in 1991 and 1993, respectively, the resistance to these cryptanalysis has been studied. In FSE2, Knudsen proposed a method of attacking block ciphers that used the higher order differential, and in FSE4, Jakobsen and Knudsen applied it to a cipher proposed by Nyberg and Knudsen. Their approach, however, requires large complexity of running time. In this paper, we improve this attack and show that our improved algorithm requires much fewer chosen texts and much less complexity than those of previous works.