Summary: The security of DES-like cryptosystems depends heavily on the strength of the Substitution boxes (S-boxes) used. The design of new S-boxes is therefore an important concern in the creation of new and more secure cryptosystems. The full set of design criteria for the S-boxes of DES has never been released and a complete set has yet to be proposed in the open literature. This paper introduces a unified S-box design framework based on information theory and illustrates how it provides immunity to the differential attack.
[For the entire collection see Zbl 0756.00008.]