Automated Dynamic Cube Attack on Block Ciphers

A little work has ever been performed in cryptanalysis of block ciphers using cube technique. This paper presents a new framework for an efficient key recovery attack on block ciphers using a kind of dynamic cube attack. In this method, a cube tester is positioned at the middle of the cipher which is extended in two directions over the maximum possible upper and lower rounds, provided that some subkey bits are guessed. It is shown that an automated algorithm for this dynamic cube attack on block ciphers can be realized. Furthermore, we show its effectiveness on two lightweight block ciphers KATAN and SIMON. Our results show that this method can break 118 and 155 out of 254 rounds of KATAN32 in non-full-codebook and full-codebook attack scenarios, respectively. In the case of SIMON32/64, we succeed to cryptanalyze 17 and 22 out of 32 rounds, in the same scenarios. Both results show that it can absolutely compete with the well-established and mature methods of cryptanalysis of block ciphers, such as linear, differential and meet in the middle attack families.