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Wednesday, 11 February 2015

What is Steganography? How to Hide Text Message behind an Image?

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What is Steganography?

Steganography term is originated from Greek word; steganos means “covered” and graphien means “writing”. Steganography is the process of hiding a secret message with ordinary content, generally images, text and then extracting the messages when it reaches the destination. Anyone else who views this message will not be able to see the hidden content.

Steganography


In steganography process, the data is first encrypted & then inserted in the normal the normal content, using special algorithm which may modify the contents of the file.

Steganography technique usually appends the data to a file, and some sophisticated steganography techniques may even disperse it throughout the file.

Program uses specially crafted algorithm which places the encrypted data in such a way that a unique pattern emerges (not visible to other programs, except it).



Common Hiding Techniques:


  • Appending data to a file.
  • Hiding Content in the unused header portion of the file near the beginning of the file contents.
  • Algorithm based dispersing of hidden message throughout the file.
  • Modification of LSP (Least Significant Bit).



Significance of Steganography:

Corporate world uses Steganography for disguising espionage attempts.

It is assumed that terrorist group makes use of Steganography to secretly communicate internally. And who knows, secret services and army uses the same.



Tools used for Steganography:

There are numerous tools used for steganography:


  • Steganos
  • S-tools for hiding data behind GIF & JPEG
  • StegHide for hiding data behind WAV and BMP
  • Invisible Secrets for hiding data behind JPEG
  • JPHide
  • Hiderman
  • and many more!

File extensions bmp, jpeg, gif, wav and mp3 are generally used to carry hidden messages.



How to Hide Text Message in an Image using CMD:

Now, we’ll be hiding our text message behind an image using CMD (command prompt). This is the very basic example of steganography (Appending data to a file).


  1. Arrange a file (in our case it’s sample.png) and a text message file (in our case it’s a.txt).
  2. Open the command Prompt (Press Window Key+R then type CMD).
  3. Locate the path to your files (in our case it’s C:\Users\Ammy5\stegano).
  4. Type the command COPY /B sample.png + a.txt newfile.jpg  OR  ECHO hey it's a secret message >> sample.png
  5. Done! Newfile.jpg contains your hidden message.

Steganography Commands



Note: If you understand DOS commands a little bit you can simple use the command

Syntax: ECHO “Steganography Hidden message here” >> sample.png

Command:  ECHO hey it's a secret message >> sample.png

This DOS command will simple echo or write your text message inside the file.


How to reveal hidden text message from image?

You just have to open your steganography’s image file in a text editor like WordPad, notepad etc.




Revealing Hidden Messages




What is Steganalysis? What are the tools Required?

Steganalysis is a study of identifying existence of hidden messages behind commonly used carrier files, the historical meaning of steganalysis means revealing the data, but in the modern world we usually use it while digitally hiding the data.

In simple words, steganalysis deal with the hidden content and identifying its existence.

Methods used for the detecting the use of Steganography:

  • Statistical Analysis
  • LSB Analysis
  • Noise floor Consistency Analysis

A few words on Steganography, There is a lot more to be learned in both Steganography and Steganalysis. You have just seen a very-very basic example which is no way used in real world for any purpose. As the above method of steganography provides next to no real security, don’t use it in real world for confidential purpose.

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