Differential-Linear Cryptanalysis of Round-Reduced SPARX-64/128

SPARX is a family of ARX-based block ciphers introduced at ASIACRYPT 2016, which is designed according to the long-trail strategy (LTS). For SPARX-64/128 with block size 64 and key size 128, the best known attack is a differential cryptanalysis of 16-round SPARX-64/128. In this paper, we further present a differential-linear cryptanalysis of SPARX-64/128. Due to the special structure of the round function, we first present some 6-round differential-linear characteristics of SPARX-64/128, then obtain two 14-round differential-linear characteristics of SPARX-64/128 by adding a 7-round differential characteristic before and a one-round linear approximation after the characteristics. By extending backwards three rounds before the 14-round differential-linear characteristics, we present a differential-linear cryptanalysis of 17-round SPARX-64/128, which covers one more round than previous work.