matlab code for video watermarking lsb


Matlab code for LSB Steganography

Data Hiding


target=imread(‘image.jpg’);
fid = fopen('message.txt','r');
F = fread(fid);
s = char(F');
fclose(fid);

sz1=size(original);
size1=sz1(1)*sz1(2);
sz2=size(F);
size2=sz2(1);

if size2> size1
fprintf('\nImage File Size %d\n',size1);
fprintf('Text File Size %d\n',size2);
disp('Text File is too Large');
else
fprintf('\nImage File Size %d\n',size1);
fprintf('Text File Size %d\n',size2);
disp('Text File is Small');
i=1;j=1;k=1;
while k<=size2
a=F(k);
o1=original(i,j,1);
o2=original(i,j,2);
o3=original(i,j,3);

[r1,r2,r3]=hidetext(o1,o2,o3,a);

target(i,j,1)=r1;
target(i,j,2)=r2;
target(i,j,3)=r3;

if(i<sz1(1))
i=i+1;
else
i=1;
j=j+1;
end
k=k+1;
end
width=sz1(1);
txtsz=size2;
n=size(original);
target(n(1),n(2),1)=txtsz;% Text Size
target(n(1),n(2),2)=width;% Image's Width
%save secret.mat target;% txtsz width;
imwrite(target,'secret.bmp','bmp');

imshow(target)

end
helpdlg('data hided succesfully in secret.bmp');


Date Retrieval


target=imread(‘stego.bmp’);
n=size(target);
txtsz=target(n(1),n(2),1);% Text Size
width=target(n(1),n(2),2);% Image's Width

i=1;j=1;k=1;
while k<=txtsz

r1=target(i,j,1);
r2=target(i,j,2);
r3=target(i,j,3);

R(k)=findtext(r1,r2,r3);

if(i<width)
i=i+1;
else
i=1;
j=j+1;
end
k=k+1;
end

fid = fopen('secret.txt','wb');
fwrite(fid,char®,'char');
fclose(fid);

helpdlg('data Retrivedsuccesfully in secret.txt');


Function for findtext

function data = findtext(redc,greenc,bluec)
txt=0;
ifbitand(redc,4)== 4
txt=bitor(txt,128);
end
ifbitand(redc,2)== 2
txt=bitor(txt,64);
end
ifbitand(redc,1)== 1
txt=bitor(txt,32);
end
ifbitand(greenc,4)== 4
txt=bitor(txt,16);
end
ifbitand(greenc,2)== 2
txt=bitor(txt,8);
end
ifbitand(greenc,1)== 1
txt=bitor(txt,4);
end
ifbitand(bluec,2)== 2
txt=bitor(txt,2);
end
ifbitand(bluec,1)== 1
txt=bitor(txt,1);
end
data=txt;
return


Function for hidetext


function[red,green,blue]=hidetext(redc,greenc,bluec,text)

red=bitand(redc,248);
green=bitand(greenc,248);
blue=bitand(bluec,252);
txt=0;

ifbitand(text,128)== 128
red=bitor(red,4);
end

ifbitand(text,64)== 64
red=bitor(red,2);
end

ifbitand(text,32)== 32
red=bitor(red,1);
end

ifbitand(text,16)== 16
green=bitor(green,4);
end

ifbitand(text,8)== 8
green=bitor(green,2);
end

ifbitand(text,4)== 4
green=bitor(green,1);
end

ifbitand(text,2)== 2
blue=bitor(blue,2);
end

ifbitand(text,1)== 1
blue=bitor(blue,1);
end

return