Steganography

Few days back i was taking part in an Hacking competetion, so there one of the cases was identifying hidden secrets between two identical looking images. We discovered that by doing a diff on those two images and checking corresponding ascii value. Untill then i was unaware that it is called Steganography. SO i just explored it..so here it is..

As from Wikipedia : Steganography is the art and science of writing hidden messages in such a way that no one apart from the intended recipient knows of the existence of the message; this is in contrast to cryptography, where the existence of the message itself is not disguised, but the content is obscured.

For example, in ancient Rome and Greece, text was traditionally written on wax that was poured on top of stone tablets. If the sender of the information wanted to obscure the message - for purposes of military intelligence, for instance - they would use steganography: the wax would be scraped off and the message would be inscribed or written directly on the tablet, wax would then be poured on top of the message, thereby obscuring not just its meaning but its very existence.

The advantage of steganography over cryptography alone is that messages do not attract attention to themselves, to messengers, or to recipients.

Generally, a steganographic message will appear to be something else: a picture, an article, a shopping list, or some other message - the covertext. Steganographic messages are often first encrypted by some traditional means, and then a covertext is modified in some way to contain the encrypted message, resulting in stegotext.

Tools can be found here:

• Neil Johnson's Steganography and Digital Watermarking site.
• StegoArchive.com.
  
• Steganos Suite.
  
• F5
  

More Resources :

• Examples showing images hidden in other images
• Steganography & Digital Watermarking
• Cryptography and Steganography
• Steganography Revealed