Image Hider 2.0 -MATLAB Program

Hide an image file inside another image file :-high quality version

This is a MATLAB based program. Image hider 2.0 is the second part of Image Hider 1.0. Image hider 2.0 is a high quality version. This software helps you to hide one image (photo) in to another image (photo). Suppose image2 is the image to be hid on image1 and the encoded image is image3. Then all the pixel details present in the image2 were encoded in to the image1. So the quality of the image2 will not be affected. Only two bits in every pixels of the image1 is used for encoding. And so the encoded image do not show any patches of the image2. So others will never suspect that image3 as encoded or it may contain any secrets.

The bits in every pixel of the image2 is split into four and placed in four different locations in image1. So it provides some sort of encryption too. So it will be hard for others to decode the hidden image.It supports formats like JPG, BMP etc

Example: Encoding section

Image1.jpg :- image on which the encoding to be done

Image2: Image to be hid

Image3: the encoded image

Example: Decoding section - using the above encoded image

Decoded image1: extracted image from image3.bmp



Decoded image2: hidden image in image3.bmp

MATLAB Program:

% Program for hiding an image inside the other

% high quality version

%By vipin.p.nair

% College of Engineering Kallooppara

% Kerala, India

% vipinpn@yahoo.com

%01-may-2009

%*****************************************************

% ---Only two bit in pixel of the image 1 is affected

% ---image2 is split & store in two diagonally opposite quadrants

% Algorithm

% the fist image is resize to double its original size

% logically the image is divided to four partitions

% the bits of the image to be hid is stored in the first image as

% shown below

% |-------------|

% |d7,d6 |d3,d2 |

% |-------------|

% |d1,d0 |d5,d4 |

% |____________|

% ****************program********************

clc; % clear the command window

clear; % clear the workspace

disp(' ');

disp(' ***** IMAGE HIDER 2.0 *****');

disp('___Program for hidimg one image inside the other image___');

disp(' ');

disp('_________________________________________________________');

task = input('---Encode :- 1 \n---Decode :- 2\n Enter your task:');

% select task

if isempty(task)

task=1;

end

if task == 1

% reads two image files

x = imread(input(' Welcome to Encoder\n Enter the first image file name: ','s'));

y = imread(input(' Enter the second image file name: ','s'));

% check compatibility

sx = size(x);

sy = size(y);

%if (sx(1) ~= sy(1))|(sx(2)~=sy(2))

x=imresize(x,[2*sy(1),2*sy(2)]);

% end

%sy=2*sy;

%

% clearing Ist files last two lsb bits & moving IInd files msb bits to lsb bits

x1 = bitand(x,uint8(252));

y1 = bitshift(y,-4);

y1_= bitand(y1,12);

y1_= bitshift(y1_,-2); % y1_ has D6 & D7

y1 = bitand(y1,3); % Y1 HAS D4,D5

% clearing II image's msb bits

y_lsb1 = bitshift(bitand(y,12),-2);

y_lsb2 = bitand(y,3);

% inserting IInd to Ist file

z=x1;

for j=1:sy(2) % y variation

for i=1:sy(1) % x variation

for k=1:3

% IInd quadrent

z(i,j,k) = bitor(x1(i,j,k), y1_(i,j,k));

% IV th quadrent

z(i+sy(1),j+sy(2),k) = bitor(x1(i+sy(1),j+sy(2),k), y1(i,j,k));

% I st quadrent

z(i+sy(1),j,k) = bitor(x1(i+sy(1),j,k), y_lsb1(i,j,k));

% IIIrd quadrent

z(i,j+sy(2),k) = bitor(x1(i,j+sy(2),k), y_lsb2(i,j,k));

end

end

end

% display the first image

figure(1)

image(x);

xlabel(' Ist Image ');

% display IInd image

figure(2);

image(y);

xlabel(' IInd Image ');

% display encoded image

figure(3);

image(z);

xlabel(' Encoded Image ');

% saving file

sav=input('Do you want to save the file y/n [y] ','s');

if isempty(sav)

sav='y';

end

if sav == 'y'

name=input('Enter a name for the encoded image: ','s');

if isempty(sav)

name='encoded_temp';

end

name=[name,'.bmp']; % concatination

imwrite(z,name,'bmp');

end

else

% Decoding encoded image

clear;

z=imread(input(' Welcome to Decoder\n Enter the image file to be decoded:','s'));

sy = size(z)/2; % take the size of input file

% xo is fist file- obtained by clearing lsb bits, yo is IInd file right

% shifting z by 4 bits

xo=bitand(z,uint8(252));

xo=imresize(xo,[sy(1),sy(2)]); % reduce the resolution to half so

%that it becoms the original image's resolution

for j=1:sy(2) % y variation

for i=1:sy(1) % x variation

for k=1:3

zout1(i,j,k) = bitshift(bitand(z(i,j,k),uint8(3)),2);

zout2(i,j,k) = bitand(z(i+sy(1),j+sy(2),k), uint8(3));

zout3(i,j,k) = bitshift(bitand(z(i+sy(1),j,k),uint8(3)),2);

zout4(i,j,k) = bitand(z(i,j+sy(2),k),uint8(3));

end

end

end

zout = bitshift((zout1+zout2),4)+zout3+zout4;

yo = zout;

% display Ist & IInd image from encoded image

figure(4);

image(xo);

xlabel('Ist Decoded Image ');

figure(5);

image(yo);

xlabel('IInd Decoded Image');

% saving file

sav=input('Do you want to save the file y/n [y] ','s');

if isempty(sav)

sav='y';

end

if sav == 'y'

name1=input('Enter a name for the first image: ','s');

name2=input('Enter a name for the second image: ','s');

if isempty(name1)

name1 = 'Ist_temp';

end

if isempty(name2)

name2 = 'IInd_temp';

end

name1 = [name1,'.bmp'];

name2 = [name2,'.bmp'];

imwrite(xo,name1,'bmp');

imwrite(yo,name2,'bmp');

end

end