Image Steganography using LSB?
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I have coded a LSB algorithm for Image Steganography. During retrieval process i'm getting different msg. Can anyone correct this code please!
Embedding code
c = imread('image.bmp');
message = 'hellokarthick'
message = strtrim(message);
m = length(message) * 8;
AsciiCode = uint8(message);
binaryString = transpose(dec2bin(AsciiCode,8));
binaryString = binaryString(:);
N = length(binaryString);
b = zeros(N,1); %b is a vector of bits
for k = 1:N
if(binaryString(k) == '1')
b(k) = 1;
else
b(k) = 0;
end
end
s = c;
height = size(c,1);
width = size(c,2);
k = 1;
for i = 1 : height
for j = 1 : width
LSB = mod(double(c(i,j)), 2);
if (k>m || LSB == b(k))
s(i,j) = c(i,j);
else
if(LSB == 1)
s(i,j) = c(i,j) - 1;
else
s(i,j) = c(i,j) + 1;
end
k = k + 1;
end
end
end
imwrite(s, 'hiddenmsgimage.bmp');
Retriever coding
s = imread('hiddenmsgimage.bmp');
height = size(s,1);
width = size(s,2);
%For this example the max size is 100 bytes, or 800 bits, (bytes * = bits
m = 800;
k = 1;
for i = 1 : height
for j = 1 : width
if (k <= m)
b(k) = mod(double(s(i,j)),2);
k = k + 1;
end
end
end
binaryVector = b;
binValues = [ 128 64 32 16 8 4 2 1 ];
binaryVector = binaryVector(:);
if mod(length(binaryVector),8) ~= 0
error('Length of binary vector must be a multiple of 8.');
end
binMatrix = reshape(binaryVector,8,100);
display(binMatrix);
textString = char(binValues*binMatrix);
disp(textString);
16 个评论
supriya
2013-3-10
Hey KARTHICK,i tried to find the flaw in ur code but couldn't! Have u found it yet??
gokul
2013-3-21
im working on the same code and experience same problem in decryption.. have u corrected d code. if so plz send me d correction.. plz do help me..
arundhati guchait
2015-3-7
编辑：Image Analyst
2015-3-7
In the retrieving part, just do a change,
for k = 1 : m
binaryVector(k) = b(k);
end
it will work.
thank u for the code. it helped us a lot.
Abhishek Barla
2015-5-7
The code is correct except for one small change.
You never added the b(k) to the LSB. So, basically, you never encoded the message. Then how will you decode it?
In the encoding process, instead of this:
if (k>m LSB == b(k)) s(i,j) = c(i,j); else if(LSB == 1) s(i,j) = c(i,j) - 1; else s(i,j) = c(i,j) + 1; end k = k + 1;
You should have:
if (k>m LSB == b(k)) s(i,j) = c(i,j); else s(i,j) = c(i,j) + b(k); k = k + 1;
Everything else remains the same. It works!!
If anything else, then feel free to reply back to this comment. Hope it eases someone's life. Good luck!
the output of extraction is wrong...
pls help to to retrieve embedded data..
JIJO JOSE
2015-11-12
in the encoding part inside the two for loops make the following change and you can decode the message accurately,
if(k<=m)
LSB = mod(double(s(i,j)), 2);
s(i,j)=s(i,j)+LSB+b(k);
k=k+1;
end
Snehal Parekh
2016-10-6
I can not hide the text information more then one page by using this code.....so please some one help me for hidding the text information in image more than one page
Walter Roberson
2016-10-6
Reshape() all of the pages together into a 2D array. Use this routine to hide the text. Reshape() back to 3D afterwards.
Sahana Konchada
2018-3-9
we are geeting the error while running this code please suggest how to recover the codes
Tommy Halim
2019-4-4
I just copying your code and I got error in my program, can you help me?
for i = 1 : height
for j = 1 : width
LSB = mod(double(c(i,j)), 2);
Walter Roberson
2019-4-4
Tommy Halim, are you using the code posted by HARTHICK ? In that code, c would be the result of imread(), and imread() never returns a struct.
Tommy Halim
2019-4-5
ah, sorry my fault. when read an image
c = imread('image.bmp');
I change it with
c = getframe(handles.axes1);
Walter Roberson
2019-4-5
You will need c(index).cdata
Tommy Halim
2019-4-5
I has been change from
c = getframe(handles.axes1);
to
c = getimage(handles.axes1);
Walter Roberson
2019-4-5
getframe() takes a copy of whatever has been rendered into the frame, no matter what kind of graphics objects.
getimage() look specifically for image objects, such as created by image() or imagesc() or imshow() . Anything else that is part of the axes will be ignored.
Tommy Halim
2019-4-5
Very helpful, thank you Walter Roberson
采纳的回答
Walter Roberson
2013-3-3
0 个投票
3 个评论
faiz ul amin
2024-4-20
% Access x y z coordinates and RGB color
% Read the point cloud from the 'Axle shaft.ply' file
ptCloud = pcread('Axle shaft.ply');
pcshow(ptCloud);
title('Axle shaft');
% Add labels to the axes
xlabel('X-axis');
ylabel('Y-axis');
zlabel('Z-axis');
% Access the location (coordinates) of all points in the point cloud
pointLocations = ptCloud.Location;
% Access the RGB color information of all points in the point cloud
pointColors = ptCloud.Color;
% Round the coordinates to the nearest integer
pointLocations = round(pointLocations);
% Display all points in the point cloud with RGB intensities
disp('All points in the point cloud (rounded to integers) with RGB intensities:');
disp([pointLocations, pointColors]);
disp('Axle shaft.ply');
faiz ul amin
2024-4-20
dear walter roberson this is a code that i write for hiding data in 3d image.this code is not complete .i acces the points ,rgb intensity.now i hide the data in rgb intensity .i dont know how to complete code.
Image Analyst
2024-4-20
@faiz ul amin If you have any questions, then ask them in a new discussion thread (not here), and attach your data and code to read it in with the paperclip icon after you read this:
更多回答（11 个）
Maged Rawash
2015-4-25
it gives you different msg because you are using JPG and jpg using lossy mode to compress .. which change the pixel value and return different msg ..
you can use that code in imwrite();
imwrite(s,'img.jpg', 'Mode','lossless' );
% not all image application will read JPG lossless
so just work on PNG, TIFF it works with me ...
to retrieve the correct massage without guessing the char number of the massage ... just store the msg length in first pixel and get it in retrieving code like this ....
c = imread(image);
c(1:1:1)= length(msg) ; %to count massage Char to easly retrive all the massage
c=imresize(c,[size(c,1) size(c,2)],'nearest');
message = msg ; %add ' .' to prevint lossing one char
message = strtrim(message);
m = length(message) * 8;
AsciiCode = uint8(message);
binaryString = transpose(dec2bin(AsciiCode,8));
binaryString = binaryString(:);
N = length(binaryString);
b = zeros(N,1);
for k = 1:N
if(binaryString(k) == '1')
b(k) = 1;
else
b(k) = 0;
end
end
s = c;
height = size(c,1);
width = size(c,2);
k = 1;
for i = 1 : height
for j = 1 : width
LSB = mod(double(c(i,j)), 2);
if (k>m || LSB == b(k))
s(i,j) = c(i,j);
elseif(LSB == 1)
s(i,j) = (c(i,j) - 1);
elseif(LSB == 0)
s(i,j) = (c(i,j) + 1);
end
k = k + 1;
end
end
imgWTxt = 'msgimage.png';
imwrite(s,imgWTxt);
----------------------------------- Retriever coding
s = imread(image);
height = size(s,1);
width = size(s,2);
m = double( s(1:1:1) ) * 8 ;
k = 1;
for i = 1 : height
for j = 1 : width
if (k <= m)
b(k) = mod(double(s(i,j)),2);
k = k + 1;
end
end
end
binaryVector = b;
binValues = [ 128 64 32 16 8 4 2 1 ];
binaryVector = binaryVector(:);
if mod(length(binaryVector),8) ~= 0
error('Length of binary vector must be a multiple of 8.');
end
binMatrix = reshape(binaryVector,8,[]);
textString = char(binValues*binMatrix);
disp(textString);
thanks For the Code ...
5 个评论
rini lya
2016-6-4
编辑：Walter Roberson
2016-6-4
Retrieval coding
Your code works even when you comment the following lines and run
s = imread(image);
height = size(s,1);
width = size(s,2);
m = double( s(1:1:1) ) * 8 ;
k = 1;
for i = 1 : height
for j = 1 : width
if (k <= m)
b(k) = mod(double(s(i,j)),2);
k = k + 1;
end
end
end
How is the hidden text retrieved then???
rose del
2019-3-12
hello .. i'm looking for a code of styganography using linear codes like hamming or simplexe thnx .
Walter Roberson
2019-3-13
That sounds like a university assignment that you would be expected to do your own work for.
Naveen Gunnam
2022-3-5
编辑：Naveen Gunnam
2022-3-5
thank you so much dude ,
faiz ul amin
2024-4-20
dear walter roberson i need some help.i need code for my project.
project title:data hiddng using 3d image as cover.) i want to hide data in 3d image.
Actually wat i did is..made an array of the the positions of the pixels whose lsb wud be changed due to the encryption method and then did some changes in ur decryption method..see
c = imread('C:\Documents and Settings\All Users\Documents\My Pictures\Sample Pictures\Sunset.jpg');
message = 'hellokarthick'
message = strtrim(message);
m = length(message) * 8;
AsciiCode = uint8(message);
binaryString = transpose(dec2bin(AsciiCode,8));
binaryString = binaryString(:);
N = length(binaryString);
b = zeros(N,1); %b is a vector of bits
for k = 1:N
if(binaryString(k) == '1')
b(k) = 1;
else
b(k) = 0;
end
end
s = c;
height = size(c,1);
width = size(c,2);
k = 1; Array=[];l=1;my=1;
for i = 1 : height
for j = 1 : width
LSB = mod(double(c(i,j)), 2);
if (k>m || LSB == b(k))
s(i,j) = c(i,j);
l=k+1;
else
if(LSB == 1)
s(i,j) = c(i,j) - 1;
else
s(i,j) = c(i,j) + 1;
Array(my)=l;
l=l+1;
my= my + 1;
end
k = k + 1;
end
end
end
imwrite(s, 'hiddenmsgimage.bmp');
Retriever code changes:
k = 1;my=1;ur=1;
for i = 1 : height
for j = 1 : width
if( k<=m )
if (my<numel(Array) && Array(my)==ur)
b(k)=~(mod(double(s(i,j)),2));
else
b(k) = mod(double(s(i,j)),2);
end
k = k + 1;
my= my + 1;
end
ur=ur+1;
end
end
9 个评论
supriya
2013-3-10
but all in vain!!
Pradeep Mallick
2014-8-15
Also I am facing this same problem i.e. ?? Error using ==> reshape To RESHAPE the number of elements must not change.
Error in ==> newsteganpgraphy at 97 binMatrix = reshape(binaryVector,8,100);
Image Analyst
2014-8-15
Your binaryVector is not 800 elements. What does
numberOfElements = numel(binaryVector) % no semicolon.
report?
oleti kameswari
2017-11-19
I am not getting correct message
Sahana Konchada
2018-3-12
I am getting while running the code in the line 29 as
Error using dec2bin Too many input arguments. Error in Receiverside (line 29) binaryString = transpose(dec2bin(AsciiCode,8));
what should I replace to get the correct output??
Walter Roberson
2018-3-12
Which MATLAB version are you using? What shows up for
which -all dec2bin
Hammad RIaz
2022-5-2
where to put this code, I need the complete code please. So far Not even a single submitted code worked for me. Can any body provide a single working code along with cover/ sego images please.
Retriever code changes:
k = 1;my=1;ur=1;
for i = 1 : height
for j = 1 : width
if( k<=m )
if (my<numel(Array) && Array(my)==ur)
b(k)=~(mod(double(s(i,j)),2));
else
b(k) = mod(double(s(i,j)),2);
end
k = k + 1;
my= my + 1;
end
ur=ur+1;
end
end
Image Analyst
2022-5-2
@Hammad RIaz, here is a version to hide text:
and attached is a version for images, and for audio. I know they both work as-is. No guarantees after you start making any modifications of your own.
If you have trouble I suggest you start your own thread and post your code and data.
ARJUN K P
2015-5-16
0 个投票
this code is not actally work correctly.. the extraction text is wrong...pls help me
the output is:
1 个评论
Image Analyst
2015-5-16
What's that garbage at the end? Don't paste all that stuff into the command window. Learn how to use a script.
Mariam Chatha
2016-9-18
0 个投票
how would the code change if we were doing MSB?
3 个评论
Walter Roberson
2016-9-18
MSB = c(i,j) / 128;
and the value to add or subtract would be 128 instead of 1.
Shah
2017-9-17
I need the MATLAB code for MSB hiding text in image stegnography
Image Analyst
2017-9-18
See my code for hiding in the LSB http://www.mathworks.com/matlabcentral/fileexchange/54155-encoding-text-into-image-gray-levels Of course if you hid it in the most significant bit, that would corrupt the image quite a bit. But nonetheless, you can use it to do that if you want.
Aishwarya Rajan
2016-11-30
0 个投票
Can anyone please explain how the LSB embedding part of the above code works?
Swati Nagpal
2018-7-21
0 个投票
Their is problem with the retrieval code it is showing different unexpected results. So if anyone got the correct result please do share the code. swatinagpal087@gmail.com
Muhammad Asfandyar Shahid
2018-8-9
0 个投票
please someone send correct code of image stegnography i will be thankfull
5 个评论
Muhammad Asfandyar Shahid
2018-8-9
编辑：Walter Roberson
2018-8-9
i have code of lsb but in retrieving garbage data has come kindly correct it.
whats wrong in retrieving code??
s = imread('image1.jpg');
height = size(s,1);
width = size(s,2);
m = double( s(1:1:1) ) * 8 ;
k = 1;
for i = 1 : height
for j = 1 : width
if (k <= m)
b(k) = mod(double(s(i,j)),2);
k = k + 1;
end
end
end
binaryVector = b;
binValues = [ 128 64 32 16 8 4 2 1 ];
binaryVector = binaryVector(:);
if mod(length(binaryVector),8) ~= 0
error('Length of binary vector must be a multiple of 8.');
end
binMatrix = reshape(binaryVector,8,[]);
textString = char(binValues*binMatrix);
disp(textString);
Walter Roberson
2018-8-9
The most obvious problem you are having is that you are using jpg . jpg uses lossy compression unless you specifically ask otherwise, so the data you write into a jpg is not the data you get back out.
Muhammad Asfandyar Shahid
2018-8-9
ok correct my code and send it back.
Walter Roberson
2018-8-9
"ok correct my code and send it back."
No. I posted the link that will get you to a list of over 300 steganography postings. Some of them have complete code, and others have discussions of how you would need to deal with situations such as yours. I have no reason to do your work.
Souradeep Mukhopadhyay
2020-7-31
编辑：Walter Roberson
2021-1-19
% Clear the existing workspace
clear all;
% Clear the command window
clc;
% Read the input image
input = imread('peppers.png');
% Convert image to greyscale
input=rgb2gray(input);
% Resize the image to required size
input=imresize(input, [512 512]);
% Message to be embedded
message='geeksforgeeks';
% Length of the message where each character is 8 bits
len = length(message) * 8;
% Get all the ASCII values of the characters of the message
ascii_value = uint8(message);
% Convert the decimal values to binary
bin_message = transpose(dec2bin(ascii_value, 8));
% Get all the binary digits in separate row
bin_message = bin_message(:);
% Length of the binary message
N = length(bin_message);
% Converting the char array to numeric array
bin_num_message=str2num(bin_message);
% Initialize output as input
output = input;
% Get height and width for traversing through the image
height = size(input, 1);
width = size(input, 2);
% Counter for number of embedded bits
embed_counter = 1;
% Traverse through the image
for i = 1 : height
for j = 1 : width
% If more bits are remaining to embed
if(embed_counter <= len)
% Finding the Least Significant Bit of the current pixel
LSB = mod(double(input(i, j)), 2);
% Find whether the bit is same or needs to change
temp = double(xor(LSB, bin_num_message(embed_counter)));
% Updating the output to input + temp
output(i, j) = input(i, j)+temp;
% Increment the embed counter
embed_counter = embed_counter+1;
end
end
end
% Write both the input and output images to local storage
% Mention the path to a folder here.
imwrite(input, 'path_to_folder\originalImage.png');
imwrite(output, 'path_to_folder\stegoImage.png');
2 个评论
Ishara Kariyawasam
2021-1-19
How to decrypt these??
Walter Roberson
2021-1-19
There is a legal distinction between steganography, which "hides" data, and "encryption". If you need to decrypt data then you need to have encrypted it... and we cannot talk about encryption here for legal reasons.
Hassan Vakani
2021-3-15
I know it is a quite late. First of all thank you for the code. Your logic doesn't have any problem. It is just the placement of the counter which is k=k+1. It should outside the outer if statement and it works.
for i = 1 : height
for j = 1 : width
LSB = mod(double(c(i,j)), 2);
if (k>m || LSB == b(k))
s(i,j) = c(i,j);
else
if(LSB == 1)
s(i,j) = c(i,j) - 1;
else
s(i,j) = c(i,j) + 1;
end
end
k = k + 1;
end
end
imwrite(s, 'hiddenmsgimage.bmp');
No need for adding the b(k) or anything else
PoXiao
2022-3-7
Why did I run Retriever Coding and get garbled code instead of my original string, and how did I extract the original image and display it? I'm really at my wit's end
s = imread('C:\Users\hiddenmsgimage.png');
height = size(s,1);
width = size(s,2);
m = double( s(1:1:1) ) * 8 ;
k = 1;
for i = 1 : height
for j = 1 : width
if (k <= m)
b(k) = mod(double(s(i,j)),2);
k = k + 1;
end
end
end
binaryVector = b;
binValues = [ 128 64 32 16 8 4 2 1 ];
binaryVector = binaryVector(:);
if mod(length(binaryVector),8) ~= 0
error('Length of binary vector must be a multiple of 8.');
end
binMatrix = reshape(binaryVector,8,[]);
textString = char(binValues*binMatrix);
msgbox(textString, 'message');
% disp(textString);
Image Analyst
2022-3-7
0 个投票
See my attached demo.
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