## Cryptology ePrint Archive: Report 2010/211

Practical-time Attack on the Full MMB Block Cipher

Keting Jia and Jiazhe Chen and Meiqin Wang and Xiaoyun Wang

Abstract: Modular Multiplication based Block Cipher (MMB) is a block cipher designed by Daemen \emph{et al.} as an alternative to the IDEA block cipher. In this paper, we give a practical-time attack on the full MMB with adaptive chosen plaintexts and ciphertexts. By the constructive sandwich distinguisher for 5 of the 6 rounds of MMB with amazingly high probability 1, we give the key recovery attack on the full MMB with data complexity $2^{40}$ and time complexity $2^{13.4}$ MMB encryptions. Then a rectangle-like sandwich attack on the full MMB is presented, with $2^{66.5}$ chosen plaintexts, $2^{64}$ MMB encryptions and $2^{70.5}$ memory bytes. By the way, we show an improved differential attack on the full MMB with data complexity of $2^{96}$ chosen plaintexts and ciphertexts, time complexity $2^{64}$ encryptions and $2^{66}$ bytes of memory.

Category / Keywords: secret-key cryptography / MMB block cipher, sandwich distinguisher, practical attack, differential attack

Date: received 15 Apr 2010, last revised 19 Apr 2010

Contact author: xiaoyunwang at tsinghua edu cn

Available format(s): PDF | BibTeX Citation

Short URL: ia.cr/2010/211

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