Another Perspective on Automatic Construction of Integral Distinguishers for ARX Ciphers

Abstract

This paper introduces a method to construct integral distinguishers for ARX ciphers. The basic idea of this method is to utilize the symmetry between the zero-correlation linear distinguishers and integral distinguishers. Combined with an automatic searching method on zero-correlation linear distinguishers of ARX ciphers, a subspace for the distinguishers is constructed. This subspace can finally be turned into an integral distinguisher based on the symmetry between these two distinguishers. Three ARX block ciphers, HIGHT, LEA and SPECK, are used to validate the effectiveness of this method. For LEA, four nine-round integral distinguishers are constructed, which is one more round than the previous best result derived with division property. For SPECK32, two more six-round integral distinguishers are constructed, whose number of active bits is reduced by one bit.