clear;clc;
x=imread('lena.bmp','bmp');
[a b c]=size(x);
N=a*b;
m(1)=input('請輸入密鑰:   ');
disp('加密中...');
for i=1:N-1
    m(i+1)=4*m(i)-4*m(i)^2;
end
m=256*m;
m=uint8(m);
n=1;
for i=1:a
    for j=1:b
        e(i,j)=bitxor(m(n),x(i,j));
        n=n+1;
    end
end
imwrite(e,'加密后的lena.bmp','bmp');
disp('加密成功');
winopen('加密后的lena.bmp');