Cryptology ePrint Archive: Report 2015/716

Linear Cryptanalysis of Reduced-Round SIMECK Variants

Nasour Bagheri

Abstract: SIMECK is a family of 3 lightweight block ciphers designed by Yang et al. They follow the framework used by Beaulieu et al. from the United States National Security Agency (NSA) to design SIMON and SPECK. A cipher in this family with K-bit key and N-bit block is called SIMECKN=K.We show that the security of this block cipher against linear cryptanalysis is not as good as its predecessors SIMON. More precisely, while the best known linear attack for SIMON32/64, using algorithm 1 of Matsui, covers 13 rounds we present a linear attack in this senario which covers 14 rounds of SIMECK32/64. Similarly, using algorithm 1 of Matsui, we present attacks on 19 and 22 rounds of SIMECK48/96 and SIMECK64/128 respectively, compare them with known attacks on 16 and 19 rounds SIMON48/96 and SIMON64/128 respectively. In addition, we use algorithm 2 of Matsui to attack 18, 23 and 27 rounds of SIMECK32/64, SIMECK48/96 and SIMECK64/128 respectively, compare them with known attacks on 18, 19 and 21 rounds SIMON32/64, SIMON48/96 and SIMON64/128 respectively.

Category / Keywords: secret-key cryptography / SIMECK, SIMON, SPECK, Linear Cryptanalysis.

Original Publication (with minor differences): INDOCRYPT 2015

Date: received 18 Jul 2015, last revised 17 Sep 2015

Contact author: na bagheri at gmail com

Available format(s): PDF | BibTeX Citation

Version: 20150917:063503 (All versions of this report)

Short URL: ia.cr/2015/716

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