Paper 2017/089

On a Linear Cryptanalysis of a Family of Modified DES Ciphers with Even Weight S-boxes

Yuri Borissov, Peter Boyvalenkov, and Robert Tsenkov

Abstract

We investigate the effect of inserting extra linearity in the Data Encryption Standard (DES) through appropriate singular linear encodings of the output of the individual S-boxes. More specifically, we examine the general situation when the output of each S-box of the DES is precoded separately into a properly constructed copy of the inherent even-weight code of length 4. The study is focused on finding multi-round linear characteristics for thus modified DES ciphers having maximal effectiveness. It turns out, depending on the particular encodings, that the effectiveness of interest may be larger but in most cases is smaller than that one for the original DES with the same number of rounds. The latter means that the complexity of successful linear cryptanalysis against these ciphers will mainly increase comparing to the DES itself. The present research extends in a natural way our previous work [Linear Cryptanalysis and Modified DES with Parity Check in the S-boxes, LNCS 9540 (2016), pp. 60 – 78].

Metadata
Available format(s)
PDF
Category
Secret-key cryptography
Publication info
Published elsewhere. MINOR revision.CYBERNETICS AND INFORMATION TECHNOLOGIES, vol. 16, No 4, 2016
DOI
10.1515/cait-2016-0063
Keywords
DESS-boxesparity checklinear cryptanalysislinear characteristics.
Contact author(s)
youri @ math bas bg
History
2017-02-10: received
Short URL
https://ia.cr/2017/089
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2017/089,
      author = {Yuri Borissov and Peter Boyvalenkov and Robert Tsenkov},
      title = {On a Linear Cryptanalysis of a Family of Modified DES Ciphers with Even Weight S-boxes},
      howpublished = {Cryptology ePrint Archive, Paper 2017/089},
      year = {2017},
      doi = {10.1515/cait-2016-0063},
      note = {\url{https://eprint.iacr.org/2017/089}},
      url = {https://eprint.iacr.org/2017/089}
}
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