IP.m

%
% Initial Permutation(IP) function
%
function [L, R] = IP(plaintext)
    IP = [58 50	42 34 26 18	10  2 ...
          60 52	44 36 28 20	12	4 ...
          62 54	46 38 30 22	14	6 ...
          64 56	48 40 32 24	16	8 ...
          57 49	41 33 25 17	9 	1 ...
          59 51	43 35 27 19	11	3 ...
          61 53	45 37 29 21	13	5 ...
          63 55	47 39 31 23	15	7];
    L = plaintext(1:8); % L in hex char
    R = plaintext(9:16);
    Lb = uint32(hex2dec(L)); % Lb in 32 bits digit
    Rb = uint32(hex2dec(R));
    Lb_temp = Lb;
    Rb_temp = Rb;
    for i = 1 : 32
        if IP(i) <= 32
            Lb = bitset(Lb, 33 - i, bitget(Lb_temp, 33 - IP(i)));
        else
            Lb = bitset(Lb, 33 - i, bitget(Rb_temp, 65 - IP(i)));
        end
        %
        if IP(i + 32) <= 32
            Rb = bitset(Rb, 33 - i, bitget(Lb_temp, 33 - IP(i + 32)));
        else
            Rb = bitset(Rb, 33 - i, bitget(Rb_temp, 65 - IP(i + 32)));
        end
    end
    L = dec2hex(Lb, 8);
    R = dec2hex(Rb, 8);
return