Full-round differential attack on TWIS block cipher

Abstract

The 128-bit block cipher TWIS was proposed by Ojha et al in 2009. It is a lightweight block cipher and its design is inspired from CLEFIA. In this paper, we first study the properties of TWIS structure, and as an extension we also consider the generalized TWIS-type structure named G-TWIS cipher whose block size and round number are 4m and n repectively, where n and m are any positive integers. Then we present a series of 10-round differential distinguishers for TWIS and an n-round differential distinguisher for G-TWIS whose probabilities are all equal to 1. It shows that 10-round TWIS cipher and n-round G-TWIS cipher can be distinguished efficiently from random permutation. © 2011 Springer-Verlag.