Assume each S-box substitution takes 8 units of time

(because of the eight 6-bit substitutions), each P-box

permutation takes 4 units of time (counting 1 unit per byte),

each expansion permutation takes 8 units of time (because of

the eight 4-bit expansions and permutations) and each initial

and final permutation takes 8 units. Compute the number of

units of time for an entire 16-round cycle of the DES.