function [s1, s2, s3, s4, s5, s6, s7, s8] = rc4cbc(k8, v)
% do CBC: k8 = new block, v = last ciphertext block
ko = [240	169	196	235	83	85	157	102];
kf = [];
xo(1) = bitxor(v(1),k8(1));
xo(2) = bitxor(v(2),k8(2));
xo(3) = bitxor(v(3),k8(3));
xo(4) = bitxor(v(4),k8(4));
xo(5) = bitxor(v(5),k8(5));
xo(6) = bitxor(v(6),k8(6));
xo(7) = bitxor(v(7),k8(7));
xo(8) = bitxor(v(8),k8(8));
kf(1:2:16) = xo;
kf(2:2:16) = ko;
an = rc4make(8, kf);
s1 = an(1);
s2 = an(2);
s3 = an(3);
s4 = an(4);
s5 = an(5);
s6 = an(6);
s7 = an(7);
s8 = an(8);