Here is a simple example of steganography. In this case a message will be include in a image. For simplicity, the message is not encrypted although it could be. outguess is the application being used. It is freely available for Linux operating systems.
The original image is that of a Thai flag. It is in JPEG format.
The message we want to send is:
Lets meet at 2pm behind the library.
The message is saved in the file mymessage.txt. To encode it into the JPEG image, creating a new JPEG image, outguess is used:
outguess -d mymessage.txt thai-1.jpg thai-2.jpg
The original image and the image with the message are given side-by-side below. Can you see any differences?
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The message can be extracted from the image:
outguess -r thai-2.jpg received.txt
Of course the contents of the file received.txt should be:
Lets meet at 2pm behind the library.
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