Impossible Differential Cryptanalysis of Piccolo Lightweight Block Cipher

This paper analyzes the Piccolo family of lightweight block ciphers against the impossible differential cryptanalysis. A combination of some ploys such as decreasing the S-box computations, finding an appropriate propagation of differentials, utilizing hash tables and using the linearity of the key-schedule as well as disregarding subkeys of two rounds lead to 12-round and 13-round impossible differential attack on Piccolo-80 and 15-round attack on Piccolo-128. The time and data complexity of the attack against Piccolo-80 is 2(55.18) and 2(36.34) for 12-round and 2(69.7) and 2(43.25) for 13-round, respectively. Moreover, the time and data complexity for 15 rounds cryptanalysis of Piccolo-128 are 2(125.4) and 2(58.7), respectively.