How can we find the minimum number of differentially active s-boxes in a block cipher (actually a Feistel network with several input cells) in a truncated characteristic form? In a recursive algorithm when we get to the situation that there are binary cases, I don't know what to do? For example when I get a xor of two nonzero characteristics, there are two cases nonzero and zero, How can recursive algorithm be applied in this state?
1 Answer
There many methods to find the number of active sboxes such as:
search algorithm , you input different scenarios , it is time-expensive process.
Matsui algorithm. code
Mixed integer linear programming.
I recommend you to try MIxed integer linear programming
References:
Differential and Linear Cryptanalysis using Mixed-Integer Linear Programming
New Impossible Differential Search Tool from Design and Cryptanalysis Aspects