“…In our experiments we use a 4-round SPN with n B = 16, m = 4 with variable S-boxes, and a fixed permutation layer given by bit permutation (1,5,9,13,2,6,10,14,3,7,11,15,4,8,12,16). As a key schedule, we use either repetition of a 16-bit key (for n K = 16), 5 independent 16-bit subkeys (for n K = 80), or a sequence of low 16-bits from a shifted 32-bit key (for n K = 32).…”