Paper 2010/211

Practical-time Attack on the Full MMB Block Cipher

Keting Jia, Jiazhe Chen, 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 $$ and time complexity $$ MMB encryptions. Then a rectangle-like sandwich attack on the full MMB is presented, with $$ chosen plaintexts, $$ MMB encryptions and $$ memory bytes. By the way, we show an improved differential attack on the full MMB with data complexity of $$ chosen plaintexts and ciphertexts, time complexity $$ encryptions and $$ bytes of memory.