A Framework for Automated Independent-Biclique Cryptanalysis

In this paper we introduce Janus, a software framework – written in Java – which is built to provide assistance in finding independent-biclique attacks for a user-chosen set of parameters, e.g., the number of rounds and dimension of the biclique. Given a certain cipher, Janus not only finds an optimal bipartite graph (biclique), but also provides an all-round carefree package of finding an optimal matching-with-precomputation step, rendering the found biclique, and determining the computational complexity of the attack. We have used the Janus framework to verify existing results on ARIA and the AES. Additionally, by using this framework, we could find the first full-round biclique attacks on all versions of the AES-like cipher BKSQ.