An Asymmetric Impossible Boomerang Attack on 7-Round AES-128

Abstract

Block cipher is the core of cryptography that provides data encryption,authentication and key management in information security.The security of block cipher is an important issue in the cryptanalysis.Based on the principle of differential cryptanalysis,this paper introduces a new cryptanalytic technique on block cipher: asymmetric impossible boomerang attack.The technique used asymmetric impossible boomerang distinguisher to eliminate wrong key material and leave the right key candidate.With key schedule considerations,techniques of looking up differential tables and re-using the data,the authors apply asymmetric impossible boomerang attack to AES-128.It is shown that attack on 7-round AES-128 requires data complexity of about 2105.18 chosen plaintexts,time complexity of about 2115.2 encryptions and memory complexity of about 2106.78 AES blocks.The presented result is better than any previous published cryptanalytic results on AES-128 in terms of the numbers of attacked rounds,the data complexity and the time complexity.