可视密码的matlab实现，附带展示ppt

南开大学信息隐藏大作业之一，实现简单的可是密码或者是叠相术，本方案是一种比较创新的方案，重点自己看

imfinfo ‘lbc1.bmp‘;
lbc=imread（‘lbc1.bmp‘）;
for i=1:ans.Height
    for j=1:ans.Width
        random=rand（）*4;
        if（random<1）
            L（ij）=1;L（ij+1）=1;L（i+1j）=0;L（i+1j+1）=0;
            B（ij）=1;B（ij+1）=0;B（i+1j）=1;B（i+1j+1）=0;
            C（ij）=1;C（ij+1）=0;C（i+1j）=0;C（i+1j+1）=1;
        else
            if（random<2）
                L（ij）=1;L（ij+1）=1;L（i+1j）=0;L（i+1j+1）=0;
                B（ij）=0;B（ij+1）=1;B（i+1j）=0;B（i+1j+1）=1;
                C（ij）=0;C（ij+1）=1;C（i+1j）=1;C（i+1j+1）=0;
            else
                if（random<3）
                    L（ij）=0;L（ij+1）=0;L（i+1j）=1;L（i+1j+1）=1;
                    B（ij）=1;B（ij+1）=0;B（i+1j）=1;B（i+1j+1）=0;
                    C（ij）=0;C（ij+1）=1;C（i+1j）=1;C（i+1j+1）=0;
                else
                    if（random<4） 
                        L（ij）=0;L（ij+1）=0;L（i+1j）=1;L（i+1j+1）=1;
                        B（ij）=0;B（ij+1）=1;B（i+1j）=0;B（i+1j+1）=1; 
                        C（ij）=1;C（ij+1）=0;C（i+1j）=0;C（i+1j+1）=1;
                    end
                end
            end
        end
    end 
end

for i=1:ans.Height
    for j=1:ans.Width
        if（lbc（ij）==0）
            random=rand（）*4;
            if（random<1）
                L（ij）=0;L（ij+1）=0;L（i+1j）=1;L（i+1j+1）=1;
                B（ij）=0;B（ij+1）=1;B（i+1j）=0;B（i+1j+1）=1;
                C（ij）=0;C（ij+1）=1;C（i+1j）=1;C（i+1j+1）=0;
            else
                if（random<2）
                    L（ij）=0;L（ij+1）=0;L（i+1j）=1;L（i+1j+1）=1;
                    B（ij）=1;B（ij+1）=0;B（i+1j）=1;B（i+1j+1）=0;
                    C（ij）=1;C（ij+1）=0;C（i+1j）=0;C（i+1j+1）=1;
                else
                    if（random<3）
                        L（ij）=1;L（ij+1）=1;L（i+1j）=0;L（i+1j+1）=0;
                        B（ij）=0;B（ij+1）=1;B（i+1j）=0;B（i+1j+1）=1;
                        C（ij）=1;C（ij+1）=0;C（i+1j）=0;C（i+1j+1）=1;
                    else
                        if（random<4）
                            L（ij）=1;L（ij+1）=1;L（i+1j）=0;L（i+1j+1）=0;
                            B（ij）=1;B（ij+1）=0;B（i+1j）=1;B（i+1j+1）=0; 
                            C（ij）=0;C（ij+1）=1;C（i+1j）=1;C（i+1j+1）=0;
                        end
                    end
                end
            end
        end
    end
end
imwrite（L‘0l.bmp‘‘bmp‘）;
imwrite（B‘2b.bmp‘‘bmp‘）;
imwrite（C‘1c.bmp‘‘bmp‘）;

L1=imread（‘0l.bmp‘）; 
B1=imread（‘2b.bmp‘）; 
C1=imread（‘1c.bmp‘）;
random=rand（）*3;
if（random<1）
    lbc=L1;lb=L1;lc=L1;bc=L1;
else
    if（random<2）
        lbc=B1;lb=B1;lc=B1;bc=B1;
    else
        lbc=C1;lb=C1;lc=C1;bc=C1;
    end
end

for i=1:ans.Height+1
    for j=1:ans.Width+1
        if（（xor（xor（L1（ij）B1（ij））C1（ij））==0）&&（xor（xor（L1（i+1j）B1（i+1j））C1（i+1j））==0）&&（xor（xor（L1（i+1j+1）B1（i+1j+1））C1（i+1j+1））==0）&&（xor（xor（L1（ij+1）B1（ij+1））C1（ij+1））==0））
            lbc（ij）=0; 
        else

 属性            大小     日期    时间   名称
----------- ---------  ---------- -----  ----
     文件      754078  2012-05-17 02:48  0l.bmp
     文件      754078  2012-05-17 02:48  1c.bmp
     文件      754078  2012-05-17 02:48  2b.bmp
     文件      754078  2012-05-17 02:48  3bc.bmp
     文件      754078  2012-05-17 02:48  4lb.bmp
     文件      754078  2012-05-17 02:48  5lc.bmp
     文件        3716  2012-05-17 02:44  lbc0.asv
     文件        3716  2012-04-22 18:37  lbc0.m
     文件       95934  2012-04-22 02:33  lbc1.bmp
     文件      754078  2012-05-17 02:48  lbc2.bmp
     文件     2351104  2012-05-17 02:50  可视密码.ppt