18-04-2011, 04:57 PM
presented By:
Aryasindhu Sahu
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Introduction to Steganography
Steganography, the art of hiding informations in information, has been a major issue since decades. Its concept has been used since many years. But the recent developments in the fields of IT and Digital Security proved that steganography is the most efficient, reliable and secure way for information exchange.
In fields like Software Development, Web Development, Modern Digital Products, Masterpieces, etc steganography has got wider acceptance. Even steganography has been a major tool for communication by the terrorists around different parts of the globe.
Looking back into the history, steganography was used by around 450 BC by Ancient Greeks who covered tablets with wax and used them to write on. They used to put melted wax over a wooden plate with carved messages. And the recipient would melt the wax to wash away and reveal the hidden message. Even in the World War invisible inks were used to hide any important information.
The modern steganography is not just using physical things for hiding data, but securing the digital products and information. Steganography can be implemented over image, audio and video files or even text documents and executable files to carry the important messages within themselves.
The whole concept behind steganography is converting the original files into their respective binary files and modifying their lowest significant bits with the information to be hidden. The file after being affected by steganography looks and behaves the same as it would have behaved earlier. So the file’s content are hidden in front of the users but the recipient knows how to decrypt and get the original information
Example: “Mad enough! Else take @ 90% per month. ” Actually hides: ‘Meet @ 9PM’
, which was a text encryption steganography.
What is Steganography?
Stega- Covered, from greek word ‘Stegos’ or roof.
-nography- writing, from greek word ‘graphia’.
• It is the art of hiding information within information.
• A form of security through obscurity.
What is it used for?
Hiding the fact that you are sending message,
Hiding several messages inside data, and
Digital Watermarking.
Hiding Several Messages:
Deniable Cryptography
Knowledge of encrypted data
No proof how much information is stored
Digital watermarking:
Not really hiding information
Important: Not modifiable
Uses the hiding property of Steganography
Recent: MPAA hides watermarks in movies.
Implementations of Steganography:-
Texts/WebPages
• Use of codebook
• Layout of texts
• Every Nth Character
• Use of whitespaces and newlines
• Difficult to detect and decode
Images
• Cover Images
• Identify Redundant data
• Replace (a subset of ) redundant bits with data
Audios
• Use of frequencies inaudible to human
• Embedding data using LSB
• Encoding Musical tones
Videos
• Visible signals (gestures, movements)
• Using Image steganographic techniques
• Using audio steganographic techniques