LSB transform for image encryption

I want to use LSB transform to encode the message in the image. The length of the bit string is less than the size of the image. I wrote a code, but when the length of the message is less, I don't know how to do the encryption. Thank you for your guidance

clc;

clear;

close all;

img=imread('cameraman.tif');

[m,n]=size(img);

message=randi([0 1],m,n);

em=img;

for i=1:m

for j=1:n

pix=dec2bin(img(i,j),8);

if (message(i,j)==0);

pix(8)='0';

else

pix(8)='1';

end

em(i,j)=bin2dec(pix);

end

end

Answer 1

[Walter Roberson]

For legal reasons we cannot discuss encryption here.

If you have two arrays and information is being transferred from a shorter array to a larger array, you have a few choices:

• you could just stop transferring and leave the larger array to be whatever is appropriate
• you could prefix size information into what is being transferred, so that the destination first retrieves the site and then knows how many locations to look at
• you could pad with a constant
• you could ensure that the data being transferred never includes a particular pattern, and then put the pattern at the place the data stops -- an "end of message" marker

Answer 2

[Image Analyst]

See my File Exchange:

https://www.mathworks.com/matlabcentral/fileexchange/54155-encoding-text-into-image-gray-levels?s_tid=srchtitle