steg.m

This m file hide an image jpeg,png in another jpeg,png image. The height and width of the secr

%                     Steganography
%
%Hide an image in another image,using LSB method
%
%There is an image in 4447.png
%Run this m file and choose 2nd option for image 4447.png to
%see that secret image


k=menu('     ','Hide an image','Recover an image');
rn=num2str(rand(1,1));

switch(k)
    case 1
        %case 1 :Encryption(hide secret image in cover image)
        %select a cover image 
[filename, pathname] = uigetfile(  {'*.jpg';'*.jpeg';'*.bmp';'*.*'}, ...
        'Select cover image');
I=imread([pathname filename]);
imageinfo_cover=imfinfo([pathname filename]);
image_height=imageinfo_cover.Height;
image_width=imageinfo_cover.Width;

equ=((image_height-1)*(image_width-mod(image_width,8)))/8;

val_red=I(:,:,1); %get the red color matrix
msgbox(['Choose a secret image with product of width and height less than ' num2str(equ)])

%select secret image
[filename, pathname] = uigetfile(  {'*.jpg';'*.png';'*.*'}, ...
         'Select secret image');
I_sec=imread([pathname filename]);
imageinfo_sec=imfinfo([pathname filename]); %get information of secret image
i_sec_height=imageinfo_sec.Height;          % secret image height 
i_sec_width=imageinfo_sec.Width;            % secret image width 

val_red=double(val_red);

%hide the secret image height  
i_sec_height_bin=de2bi(i_sec_height,16);
val_red(1,1:16)=bitset(val_red(1,1:16),1,i_sec_height_bin);

%hide the secret image width  
i_sec_width_bin=de2bi(i_sec_width,16);
val_red(1,17:32)=bitset(val_red(1,17:32),1,i_sec_width_bin);

I(:,:,1)=val_red;  

i_sec_length=i_sec_height*i_sec_width;
I_sec_bin=zeros(i_sec_length*3,8);


I_sec_bin=de2bi(double(I_sec));    %convert the secret image to binary
Ipix_counter=1;                    %set a counter for the  pixels


len=mod(image_width,8);            
len=image_width-len;               

for count_hi=2:image_height
    count_wi=1;
    for count_wi=1:8:len-8
          val_red(count_hi,count_wi:count_wi+7)=...
                bitset(val_red(count_hi,count_wi:count_wi+7),1,I_sec_bin(Ipix_counter,:));
        
         Ipix_counter=Ipix_counter+1;
       if Ipix_counter>i_sec_length*3
         break;
       end

    
    end
       if Ipix_counter>i_sec_length*3
         break;
       end
      
end

I(:,:,1)=val_red;
imwrite(I,[rn(3:end) '.png'],'png');
msgbox(['The secret image ' filename ' is in ' rn(3:end) '.png'])

case 2
%case 2:Dercyption(Reocver the secret image from cover image)

%select the  encrypted cover image 
[filename, pathname] = uigetfile(  {'*.png'}, ...
        'Select an encrypted cover image');
I=imread([pathname filename]);    

imageinfo_cover=imfinfo([pathname filename]);%cover image information
image_height=imageinfo_cover.Height;         %cover image height
image_width=imageinfo_cover.Width;           %cover image width

val_red=I(:,:,1);                            %get the red color matrix

%extract the secret image height and width from 1st 32pixel of cover image
i_sec_height=bi2de(bitget(double(val_red(1,1:16)),1));
i_sec_width=bi2de(bitget(double(val_red(1,17:32)),1));
i_sec_length=i_sec_height*i_sec_width;

I_sec_bi=zeros(i_sec_length*3,8);%initialize a zero matrix
Ipix_counter=1;                              %counter for pixels

len=mod(image_width,8);            
len=image_width-len;               

for count_hi=2:image_height
    count_wi=1;
    for count_wi=1:8:len-8
       I_sec_bi(Ipix_counter,1:8)=...
       bitget(val_red(count_hi,count_wi:count_wi+7),1);
        
       Ipix_counter=Ipix_counter+1;
       if Ipix_counter>i_sec_length*3
         break;
       end

     
    end
        if Ipix_counter>i_sec_length*3
         break;
       end
end

image1=reshape(bi2de(I_sec_bi),i_sec_height,i_sec_width,3);
image1=uint8(image1);
imwrite(image1,[num2str(rn(3:end)) '.png'],'png');
msgbox(['The secret image '  rn(3:end) '.png is extracted from ' filename ' ,it is in your current directory']);

end