Inside des xo=IP(m =Loro 16 Rounds,i=1,2,,16 R -1 R;:=Ln1f(R1,K1)2 where f(R21,k1)=P(S(E(R:1)K1) with operations e(expansion) S(S-box lookup), and P some (permutation) C=IP(LI6R16)Inside DES • x0 = IP(m) = L0R0 . • 16 Rounds, i = 1, 2, …, 16: Li := Ri-1 , Ri := Li-1  f (Ri-1 , Ki ), where f (Ri-1 , Ki ) = P(S(E(Ri-1 )  Ki )), with operations E (expansion), S (S-box lookup), and P some (permutation). • c = IP-1 (L16R16)