Impossible Differential Attack on Reduced Round SPARX-128/256

Muhammad ELSHEIKH  Mohamed TOLBA  Amr M. YOUSSEF  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E101-A   No.4   pp.731-733
Publication Date: 2018/04/01
Online ISSN: 1745-1337
Type of Manuscript: LETTER
Category: Cryptography and Information Security
Keyword: 
SPARX,  block ciphers,  cryptanalysis,  impossible differential attacks,  

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Summary: 
SPARX-128/256 is one of the two versions of the SPARX-128 block cipher family. It has 128-bit block size and 256-bit key size. SPARX has been developed using ARX-based S-boxes with the aim of achieving provable security against single-trail differential and linear cryptanalysis. In this letter, we propose 20-round impossible differential distinguishers for SPARX-128. Then, we utilize these distinguishers to attack 24 rounds (out of 40 rounds) of SPARX-128/256. Our attack has time complexity of 2232 memory accesses, memory complexity of 2160.81 128-bit blocks, and data complexity of 2104 chosen plaintexts.