Security Analysis of CIKS-128 and CIKS-128H Using Key Schedule Weaknesses

In this paper, we show that CIKS-128 and CIKS-128H are vulnerable to related-key differential attacks. We first describe how to construct their full-round related-key differential characteristics with high probabilities and then we exploit them to break the full-round CIKS-128 and CIKS-128H with 2
⁴⁴
,and 2
⁴⁸
data and time complexities, respectively. These woks are corrections of Lee et al.'s results [7].