S-Box ·48bits==>32bts.(8*6==>8*4) 2 bits used to select amongst 4 permutations for the rest of the 4-bit quantity 2 bits row I3 O1 O2 4 O3 15 04 4 bits 16 column 820 S-Box • 48 bits ==> 32 bits. (8*6 ==> 8 *4) • 2 bits used to select amongst 4 permutations for the rest of the 4-bit quantity 2 bits row Si i = 1,…8. I1 I2 I3 I4 I5 I6 O1 O2 O3 O4 4 bits column