Cryptology ePrint Archive: Report 2015/734

On the Security of Extended Generalized Feistel Networks

Manoj Kumar and Saibal K. Pal and Anupama Panigrahi

Abstract: In this paper, we analyze the security claims of Extended Generalized Feistel Networks (EGFNs) schemes proposed by Berger et al [1]. We provide impossible differentials for 10 rounds of EGFNs with 16 branches which add up one round to the claim of 9 rounds in the impossible differential trail. Therefore, impossible differential trail covers 10 rounds for the EGFNs scheme, which is the best result on impossible differentials of EGFNs so far. We also provide several 10 round impossible differential trails to attack EGFNs based new cipher proposals. u–method is also used by authors to assert their claim for maximum number of rounds in impossible differential trails of EGFNs. This analysis indicates that u-method does not provide optimal results for this scheme.

Category / Keywords: secret-key cryptography , Feistel Network, Generalized Feistel Network, Impossible Differential Cryptanalysis, u-method

Date: received 22 Jul 2015, last revised 27 Jul 2015, withdrawn 31 Mar 2016

Contact author: mktalyan at yahoo com

Available format(s): (-- withdrawn --)


Version: 20160331:063525 (All versions of this report)

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