Results of Switching-Closure-Test on FEAL (Extended Abstract)

The closure tests, CCT and MCT, were introduced to analyze the algebraic properties of cryptosystems by Kaliski et al. [KaRiSh]. If a cryptosystem is closed, the tests give the same results “Fail” and the cryptosystem might be breakable. Though CCT requires much less memory and time than MCT, we cannot apply CCT to check cryptosystems having the same data and key block lengths such as FEAL with non-parity mode. Because CCT utilizes the differences in data and key block lengths.