I did PVD steganography for hiding text in color image can any one please help me to use the same code for hiding color image inside color cover image in matlab?

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Anushka 2015-10-4

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https://ww2.mathworks.cn/matlabcentral/answers/246673-i-did-pvd-steganography-for-hiding-text-in-color-image-can-any-one-please-help-me-to-use-the-same-c

编辑： aya jaradat 2022-5-31

I did PVD steganography for hiding text in color image can any one please help me to use the same code for hiding color image inside color cover image in matlab? The code for hiding text inside color cover image and extracting from it is given below.

clc;
close all;
clear;
%%%%%%%%%%%%%%%%%%%%%%%Reading a Secret Text File %%%%%%%%%%%%%%%%%%%%%%%%
file_id = fopen('message.txt','r');
file_content = fread(file_id);
file_length = length(file_content);
in = [];
in = [in dec2bin(file_length,20)]; %character to binary conversion 
for i=1:file_length  
      in=[in dec2bin(file_content(i),7)];
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%Reading Cover Image %%%%%%%%%%%%%%%%%%%%%%%%%%%
cover_image = imread('cover_image.bmp'); %get cover image      
red = cover_image(:,:,1); %seperating rgb values 
blue = cover_image(:,:,2);
green = cover_image(:,:,3);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%Embedding Data %%%%%%%%%%%%%%%%%%%%%%%%%%%%%
color = red; %red color selected for embedding
[r,c] = size(color);
final = double(color); 
next=0;
capacity=0; %total no of bits that can be embedded
for x=0:1:r-1 
      for y=0:2:c-1
          enable = 1; %enable=0 when new pixels may fall off the boundary
          p = color(1+x,1+y:2+y); %block of two pixels, pi & pi+1
          p = double(p);
          d = p(1,2) - p(1,1); %d = difference between 2 pixel
          d_abs = abs(d); %absolute difference
          lb=[0 8 16 32 64 128]; %lowerbound
          ub=[7 15 31 63 127 255]; %upperbound
          for i=1:1:6 %test the R boundary
              if((d_abs >= lb(i)) && (d_abs <= ub(i))) %selecting range
                  %check if any pixel in a block fall off the boundary [0,255]
                  even2 = mod(d,2); 
                  m2 = ub(i) - d;
                  if (even2 == 0)
                      Pcheck=[p(1,1)-floor(m2/2) p(1,2)+ceil(m2/2)];
                  else
                      Pcheck=[p(1,1)-ceil(m2/2) p(1,2)+floor(m2/2)];
                  end
                  if(Pcheck(1)<0 || Pcheck(2)<0 || Pcheck(1)>255 || Pcheck(2)>255)
                      enable = 0;
                      break
                  end
                  n = ub(i)-lb(i)+1; %quantization width of range
                  t = floor(log2(n)); %maximum bit can be embedded in 2 pixels
                  capacity=capacity+t; %max capacity of the cover image 
                  %check if next exceeds the length of message
                  if(next>length(in)) 
                      m=0;
                  %check if next+t exceeds the length of message
                  elseif(next+t>length(in)) 
                      if(1+next>=length(in))
                          k=zeros(1,t);
                      else
                          k=in(1+next:length(in));
                      end
                      diff =next+t-length(in);
                      k1=zeros(1,t);
                      if(diff>0)
                          for j=1:next+t-length(in)
                              k1(j)=k(j);
                          end
                      end
                      k=k1;
                      next=next+t;
                      k=bin2dec(char(k));
                      if(1+next>length(in))
                          m=0;
                      else
                          if(d >= 0)
                              dnew = k + lb(i);
                          else
                              dnew = -(k + lb(i));
                          end
                          m = dnew - d;
                      end
                  %if next is less than the length of message
                  else 
                      k=in(1+next:t+next);
                      next=next+t;
                      k=bin2dec(char(k));
                      if(d >= 0)
                          dnew = k + lb(i);
                      else
                          dnew = -(k + lb(i));
                      end
                      m = dnew - d;
                  end
              end
          end
          if (enable == 1)
              even = mod(d,2);
              if (even == 0)
                  P0=[p(1,1)-floor(m/2) p(1,2)+ceil(m/2)];
              else
                  P0=[p(1,1)-ceil(m/2) p(1,2)+floor(m/2)];
              end
              final(1+x,1+y)=P0(1,1);
              final(1+x,2+y)=P0(1,2);
          end
      end
  end
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%Creating Stego-Image %%%%%%%%%%%%%%%%%%%%%%%%%%
if(next>length(in))
      disp('Message Embedded Successfully');
      final = uint8(final);
      stego_image = cat(3,final,blue,green);
      imwrite(stego_image,'stego_image.bmp');
      fclose('all');
  else %check if the cover is samll for the given messege to be embedded
      error('Cover Image is too small for the given messege to be embedded, please replace cover image with the larger one.');
  end
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
clc;
clear all;
%%%%%%%%%%%%%%%%%%%%%%%%%%%Reading Stego Image %%%%%%%%%%%%%%%%%%%%%%%%%%%
stego_image = imread('stego_image.bmp');
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%Extracting Data %%%%%%%%%%%%%%%%%%%%%%%%%%%%
color = stego_image(:,:,1); %red color selected where data is embedded
[r,c]=size(color);
j=0;
msg = [];
flag = 0;
length=0;
enable = 1;
for x=0:1:r-1
      for y=0:2:c-1
          if (enable == 1) %enable=0 when any pixels may fall off the boundary
              gp = color(1+x,1+y:2+y); %block of 2 pixels, pi & pi+1
              gp = double(gp);
              d  = gp(1,2) - gp(1,1); %d = difference between 2 pixel
              nd = abs(d); %absolute difference
              lb = [0 8 16 32 64 128]; %lowerbound
              ub = [7 15 31 63 127 255]; %upperbound
              for i=1:1:6 %test the R boundary
                  if(nd>=lb(i)&&nd<=ub(i))
                      %check if any pixel in a block fall off the boundary [0,255]
                      even2 = mod(d,2); 
                      m2 = ub(i) - d;
                      if (even2 == 0)
                          Pcheck=[gp(1,1)-floor(m2/2) gp(1,2)+ceil(m2/2)];
                      else
                          Pcheck=[gp(1,1)-ceil(m2/2) gp(1,2)+floor(m2/2)];
                      end
                      if(Pcheck(1)<0 || Pcheck(2)<0 || Pcheck(1)>255 || Pcheck(2)>255)
                          break
                      end
                      w = ub(i)-lb(i)+1; %quantization width of range
                      t=log2(w); %maximum bit can be embedded between 2 pixel
                      b = nd - lb(i);
                      k=dec2bin(b,t);
                      msg = [msg k];
                      j=j+t;
                      if(flag==0 && j>=20)
                          length=bin2dec(msg(1:20))+3; %possible 3 char error
                          length=length*7;
                          flag=1;
                      end
                      if(flag==1 && j>=length)
                          j=1;
                          for i=20:7:length-7
                              finaltxt(j)=bin2dec(msg(1+i:7+i));
                              j=j+1;
                          end
                          fid=fopen('output.txt','w');
                          fwrite(fid,finaltxt);
                          disp('Message Extracted Successfully');
                          fclose('all');
                          enable = 0;
                      end
                  end
              end
          end
      end
  end
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

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A A 2017-5-23

hi , can you help me please , my project it about hiding secret message in an image , I find the code valid for me, but do not know why do not implement with me, please can you help thanks

Walter Roberson 2017-5-23

A A: please see https://www.mathworks.com/matlabcentral/answers/?term=tag%3A%22steganography%22 as there are many posts on the topic, some of which contain complete code.

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Answer 1

Walter Roberson 2015-10-4

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/246673-i-did-pvd-steganography-for-hiding-text-in-color-image-can-any-one-please-help-me-to-use-the-same-c#answer_194662

编辑：Walter Roberson 2015-10-4

在 MATLAB Online 中打开

Change the line

file_id = fopen('message.txt','r');

to instead refer to the image file that you want to hide, and change

in=[in dec2bin(file_content(i),7)];

to use 8 instead of 7.

When you are decoding, expect 8 bits per byte instead of 7.

With this change, you can hide any data file that is stored as a sequence of bites, provided that the length is no more than (2^20 - 1), a limit imposed in your line

in = [in dec2bin(file_length,20)]; %character to binary conversion

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Anushka 2015-10-5

编辑：Walter Roberson 2015-10-5

在 MATLAB Online 中打开

Thank you Sir, I did as you have told but now the insertion part works well and the stego image is formed but the extraction part is not working can you please help me . There is no error in the algorithm since it worked well for text data

for dim = 1: 3
    em = im2;
    em = em(:);
    len = length(em);
    in = [];
      in=[in dec2bin(len,30)];
      for i=1:len         %character convert to binary
          in=[in dec2bin(em(i),8)];
      end
      a = im1(:,:,dim);    %get cover image
      [r,c]=size(a);
      final=double(a);
      next=0;
      capacity=0;
   %total no of bits that can be embedded
for x=0:1:r-1 
      for y=0:2:c-1
          enable = 1; %enable=0 when new pixels may fall off the boundary
       p = a(1+x,1+y:2+y); %block of two pixels, pi & pi+1
          p = double(p);
          d = p(1,2) - p(1,1); %d = difference between 2 pixel
          d_abs = abs(d); %absolute difference
          lb=[0 8 16 32 64 128]; %lowerbound
          ub=[7 15 31 63 127 255]; %upperbound
          for i=1:1:6 %test the R boundary
              if((d_abs >= lb(i)) && (d_abs <= ub(i))) %selecting range
                  %check if any pixel in a block fall off the boundary [0,255]
                  even2 = mod(d,2); 
                  m2 = ub(i) - d;
                  if (even2 == 0)
                      Pcheck=[p(1,1)-floor(m2/2) p(1,2)+ceil(m2/2)];
                  else
                      Pcheck=[p(1,1)-ceil(m2/2) p(1,2)+floor(m2/2)];
                  end
                  if(Pcheck(1)<0 || Pcheck(2)<0 || Pcheck(1)>255 || Pcheck(2)>255)
                      enable = 0;
                      break
                  end
                  n = ub(i)-lb(i)+1; %quantization width of range
                  t = floor(log2(n)); %maximum bit can be embedded in 2 pixels
                  capacity=capacity+t; %max capacity of the cover image 
                  %check if next exceeds the length of message
                  if(next>length(in)) 
                      m=0;
                  %check if next+t exceeds the length of message
                  elseif(next+t>length(in)) 
                      if(1+next>=length(in))
                          k=zeros(1,t);
                      else
                          k=in(1+next:length(in));
                      end
                      diff =next+t-length(in);
                      k1=zeros(1,t);
                      if(diff>0)
                          for j=1:next+t-length(in)
                              k1(j)=k(j);
                          end
                      end
                      k=k1;
                      next=next+t;
                      k=bin2dec(char(k));
                      if(1+next>length(in))
                          m=0;
                      else
                          if(d >= 0)
                              dnew = k + lb(i);
                          else
                              dnew = -(k + lb(i));
                          end
                          m = dnew - d;
                      end
                  %if next is less than the length of message
                  else 
                      k=in(1+next:t+next);
                      next=next+t;
                      k=bin2dec(char(k));
                      if(d >= 0)
                          dnew = k + lb(i);
                      else
                          dnew = -(k + lb(i));
                      end
                      m = dnew - d;
                  end
              end
          end
          if (enable == 1)
              even = mod(d,2);
              if (even == 0)
                  P0=[p(1,1)-floor(m/2) p(1,2)+ceil(m/2)];
              else
                  P0=[p(1,1)-ceil(m/2) p(1,2)+floor(m/2)];
              end
              final(1+x,1+y)=P0(1,1);
              final(1+x,2+y)=P0(1,2);
          end
      end
  end
   stego_image(:,:,dim)=final;
  end
    end
[row,col,dim]=size(Image);
% %RecIm=[];
% j=0;
% length=0;
    for p = 1:dim
      layer = Image(:,:,p);
      msg = [];
  flag = 0;
  length=0;
  [row,col,dim]=size(Image);
  j=0;
  finaltxt=[];
  enable = 1;
  % [r1 c1]=size(YourRGBImage);
  % length=r1*c1;
  for x=0:1:row-1
      for y=0:2:col-1
          if (enable == 1) %enable=0 when any pixels may fall off the boundary
              gp = layer(1+x,1+y:2+y); %block of 2 pixels, pi & pi+1
              gp = double(gp);
              d  = gp(1,2) - gp(1,1); %d = difference between 2 pixel
              nd = abs(d); %absolute difference
              lb = [0 8 16 32 64 128]; %lowerbound
              ub = [7 15 31 63 127 255]; %upperbound
              for i=1:1:6 %test the R boundary
                  if(nd>=lb(i)&&nd<=ub(i))
                      %check if any pixel in a block fall off the boundary [0,255]
                      even2 = mod(d,2); 
                      m2 = ub(i) - d;
                      if (even2 == 0)
                          Pcheck=[gp(1,1)-floor(m2/2) gp(1,2)+ceil(m2/2)];
                      else
                          Pcheck=[gp(1,1)-ceil(m2/2) gp(1,2)+floor(m2/2)];
                      end
                      if(Pcheck(1)<0 || Pcheck(2)<0 || Pcheck(1)>255 || Pcheck(2)>255)
                          break
                      end
                      w = ub(i)-lb(i)+1; %quantization width of range
                      t=log2(w); %maximum bit can be embedded between 2 pixel
                      b = nd - lb(i);
                      k=dec2bin(b,t);
                      msg = [msg k];
                      j=j+t;
  % %                     length=length(msg);
  %                     
  %                      
                     if(flag==0 && j>=30)
                        length=bin2dec(msg(1:30))+3; %possible 3 char error 
                        length=length*7;
                        flag=1;
                     end
                    if(flag==1 && j>=length)
                        w1=1;
                        for i=30:7:length-7
                            finaltxt(w1)=bin2dec(msg(1+i:7+i));
                            w1=w1+1;
                          end
   RecIm(:,:,p) = reshape(finaltxt,[8 8]); 
                         enable = 0;
                      end
                  end
              end
          end
  end
end
end
end

PoXiao 2022-3-9

Have you solved the problem of extracting pictures? I also want to know what to do

aya jaradat 2022-5-31

编辑：aya jaradat 2022-5-31

Have you solved the problem of extracting images?

Please, I am facing the same problem

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I did PVD steganography for hiding text in color image can any one please help me to use the same code for hiding color image inside color cover image in matlab?

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I did PVD steganography for hiding text in color image can any one please help me to use the same code for hiding color image inside color cover image in matlab?

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