Impossible differential cryptanalysis of 13-round CLEFIA-128

Block cipher plays an important role in the domain of information security. CLEFIA is a 128-bit block cipher proposed by SONY Corporation in FSE 2007. Using the previous 9-round impossible differentials, the redundancy in the key schedule and the early-abort technique, we present the first successful impossible differential cryptanalysis of 13-round CLEFIA-128 in this paper. The data and time complexities of the attack with the whitening layers are 2119.4 and 2125.52, respectively. And for the attack without the whitening layers, more relationships among the subkeys can be used, thus the data and time complexities are reduced to 2111.3 and 2117.5, respectively. As far as we know, the presented results are the best compared with the previously published cryptanalytic results on reduced-round CLEFIA-128.