Inside des =P(m)=L0R0 16 Rounds,j=1,2,…,16 尺;:=L;1f(R1,K), where f(R1,K)=P(S(E(R:1)K) with operations E(expansion) s(S-box lookup), and P some (permutation) c=|P1(L16R16) 1010 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)