Abstract:
We model AES-like algorithms by XSLP-ciphers having uniformly diffusive permutations $P$ and fixed linear (differential) branch number $\rho$ of blocks of transformation matrices $L$. For all admissible values of $\rho$ and arbitrary number of rounds the exact lower bound for the number of active $\mathrm{S}$-boxes in systems of linear (differential) probabilistic relations is obtained.
Key words:AES, AES-like algorithms, XSLP-ciphers, linear cryptanalysis, differential cryptanalysis, active $\mathrm{S}$-boxes.