Improved impossible differential cryptanalysis of 7-round AES-128

Abstract

Using a new 4-round impossible differential in AES that allows us to exploit the redundancy in the key schedule of AES-128 in a way more effective than previous work, we present a new impossible differential attack on 7 rounds of this block cipher. By this attack, 7-round AES-128 is breakable with a data complexity of about 2106 chosen plaintexts and a time complexity equivalent to about 2110 encryptions. This result is better than any previously known attack on AES-128 in the single-key scenario. © 2010 Springer-Verlag Berlin Heidelberg.