How can you hide information inside a jpg or gif photo?

Question

How can I write some information inside a photo file like jpg or gif without destroying the image? and of course without showing it on the photo since the whole idea is to s

Answer 1

You can concatenate a gif and a zip (the information you want to hide) into one file. Gifs are read from the start of the file, while zips are read from the end of the file.

To create such a file in linux:

$ cat file1.gif >> outfile.gif
$ cat file2.zip >> outfile.gif

The resulting file should have the size of file1.gif and file2.zip together and should be openable by any gif viewer and zip file handler.

Answer 2

If you want to hide data (text, another image, whatever) in a jpeg file, you can simply append it to the end of the file. When the image is viewed, you'll only see the original image and your added data will be ignored.

While not a super-duper way of hiding data, this is a good way of hiding another jpeg, as if anyone opens the file in notepad or a hex editor, they will probably not notice that there are two jpegs and not one because the end of the second image will just look like the first anyway.

Answer 3

You don't need any type of advanced tool to hide a file in an image –– you just you need to know some basic DOS commands… just follow the link below, to see how to do this (it’s a short description of image steganography):

https://www.youtube.com/watch?v=ox9ArqXtaWw&list=PLqEKOAKK4IbSTfDJZE_lH-DiOjOzZUczx&index=2

Answer 4

I'm sure there are many ways. Here's one:

In a photograph, minor variations in color would often be unnoticable to the naked eye, or even if noticed, might easily be mistaken for flaws in the quality of the picture.

So to take a simple example, suppose you had a gray-scale GIF image where the pallette is arranged in order from white to black with a smooth range of grays in between. I'm not sure how much you know about graphic file formats, but in GIF you have one byte per pixel, with each possible byte value mapping to some specific color. So in this case we could say pallette #0=RGB(0,0,0), pallette #1=RGB(1,1,1), ... palette #255=RGB(255,255,255).

Then you take an ordinary, real photograph. Break your secret message into individual bits. Set the last bit of each pallette index number to successive bits of your message.

For example, suppose the first eight pixels of the original photo are, say, 01 00 C9 FF FF C8 42 43. Your message begins with the letter "C", ascii code 0110 0111. So you change the last bit of the first byte to 0, changing the byte from 01 to 00. You change the last bit of the second byte to 1, changing the byte from 00 to 01. You change the last bit of the third byte to 1. It's already 1, so that makes no difference. Etc. You end up with the coded 8 bytes being 00 01 C9 FE FF C9 43 43.

The changes to the colors would be so subtle that it's unlikely that anyone looking at the picture would notice. Even if they did notice, unless they had a reason to be suspicious, they would likely just conclude that the picture was of less-than-perfect quality.

Of course nothing says you have to use 1 bit per byte for the secret message. Depending on how much degradation in quality you think you can get away with, you could use 2 bits per byte, or just change 1 bit in every other byte, etc.

Of course the same technique can be used with color photos: change the last bit in each of the RGB components to encode 3 bits per pixel, etc.

Answer 5

In windows you can use simple command to hide archive in image : copy /b cat.jpg + Documents.rar cat_new.jpg. And then use for example winrar to extract data ftom image as from archive.
But better way is to use Steganography.
simple program for it for linux and windows : http://linux01.gwdg.de/~alatham/stego.html
using this program you will use pass phrase, without it nobody even will know, that you hided some data in picture ))

Answer 6

You can store some information in image metadata. In fact that's how man digital cameras 'tag' the photos their making (camera model, date and time, GPS coords etc.).

This data format is called EXIF (Exchangeable Image File Format). There are a lot of examples how to use it in programming languages. Here's the example in Java.

If you want to prevent users from reading this data you can encrypt them somehow, but they will always be able to remove it from your picture (by opening in Photoshop and using Save As for example).