A note on Weak Keys of PES, IDEA and some Extended Variants

Jorge Nakahara Jr; Bart Preneel; Joos Vandewalle

Paper 2002/152

A note on Weak Keys of PES, IDEA and some Extended Variants

Jorge Nakahara Jr, Bart Preneel, and Joos Vandewalle

Abstract

This paper presents an analysis of the PES cipher in a similar setting as done by Daemen et al. at Crypto'93 for IDEA. The following results were obtained for 8.5 round PES: a linear weak-key class of size $2^{48}$ ; two distinct differential weak-key classes of size $2^{41}$ ; two differential-linear weak-key classes of size $2^{62}$ . For 17-round PES (double-PES): a linear weak-key class of size , and a differential weak-key class of size were found. Daemen suggested a modified key schedule for IDEA in order to avoid weak keys. We found a differential weak-key class of size for 2.5-round IDEA under his redesigned key schedule, and differential-linear relations for 3.5-round IDEA.

Note: comments are welcome !

Metadata

Available format(s): PDF PS
Category: Secret-key cryptography
Publication info: Published elsewhere. Unknown where it was published
Keywords: cryptanalysis block ciphers
Contact author(s): jorge nakahara @ esat kuleuven ac be
History: 2002-10-15: received
Short URL: https://ia.cr/2002/152
License: CC BY

BibTeX

@misc{cryptoeprint:2002/152,
      author = {Jorge Nakahara Jr and Bart Preneel and Joos Vandewalle},
      title = {A note on Weak Keys of {PES}, {IDEA} and some Extended Variants},
      howpublished = {Cryptology {ePrint} Archive, Paper 2002/152},
      year = {2002},
      url = {https://eprint.iacr.org/2002/152}
}