Cryptology ePrint Archive: Report 2015/557

Improved All-Subkeys Recovery Attacks on FOX, KATAN and SHACAL-2 Block Ciphers

Takanori Isobe and Kyoji Shibutani

Abstract: The all-subkeys recovery (ASR) attack is an extension of the meet-in-the-middle attack, which allows evaluating the security of a block cipher without analyzing its key scheduling function. Combining the ASR attack with some advanced techniques such as the function reduction and the repetitive ASR attack, we show the improved ASR attacks on the 7-round reduced FOX64 and FOX128. Moreover, the improved ASR attacks on the 119-, 105- and 99-round reduced KATAN32, KATAN48 and KATAN64, and the 42-round reduced SHACAL-2 are also presented, respectively. As far as we know, all of those attacks are the best single-key attacks with respect to the number of attacked rounds in literature.

Category / Keywords: secret-key cryptography / block cipher, meet-in-the-middle attack, all-subkeys recovery attack

Original Publication (with minor differences): IACR-FSE-2014

Date: received 5 Jun 2015

Contact author: Takanori Isobe at jp sony com

Available format(s): PDF | BibTeX Citation

Version: 20150615:071004 (All versions of this report)

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