Biclique Cryptanalysis on the Full Crypton-256 and mCrypton-128

Abstract EN

Biclique cryptanalysis is an attack which reduces the computational complexity by finding a biclique which is a kind of bipartite graph.

We show a single-key full-round attack of the Crypton-256 and mCrypton-128 by using biclique cryptanalysis.

In this paper, 4-round bicliques are constructed for Crypton-256 and mCrypton-128.

And these bicliques are used to recover master key for the full rounds of Crypton-256 and mCrypton-128 with the computational complexities of 2253.78 and 2126.5, respectively.

This is the first known single-key full-round attack on the Crypton-256.

And our result on the mCrypton-128 has superiority over known result of biclique cryptanalysis on the mCrypton-128 which constructs 3-round bicliques in terms of computational time complexity.