Key schedule Key schedule Ki, K2,..., K16 Discard the parity-check bits of K Compute PC-1(k)=CO Do3 Where PC-1 is a fixed permutation Co, Do left and right halves, 28-bit each Forj=1,2,…,16: C;:=LS(C11),D;:=LS(D11), where LS, left cyclic shift of one (F1, 2, 9, 16)or two positions (else) K;:=PC-2(CD), PC-2 fixed permutation selecting 48 bits25 Key schedule • Key schedule K1 , K2 ,…, K16 ▪ Discard the parity-check bits of K. ▪ Compute PC-1(K) = C0D0 , where PC-1 is a fixed permutation, C0 , D0 left and right halves, 28-bit each. ▪ For i = 1, 2, …, 16: Ci := LSi (Ci-1 ), Di := LSi (Di-1 ), where LSi left cyclic shift of one (i= 1, 2, 9, 16) or two positions (else), Ki := PC-2(CiDi ), PC-2 fixed permutation selecting 48 bits