30-05-2012, 02:52 PM
Steganography
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What is Steganography?
The art of writing in code.
Hiding information by embedding messages within other messages.
Only the person receiving the message can decode it, but they must have to the proper code to do so.
Examples
Fishing freshwater bends and saltwater coasts rewards anyone feeling stressed. Resourceful anglers usually find masterful leapers fun and admit swordfish rank overwhelming anyday.
Send Lawyers, Guns, and Money.
DIGITAL APPROACHES
Today, it often exists within digital formats.
It makes use of seemingly innocent cover files such as text, audio, and image files.
The embedded message may be anything that can be encoded in binary.
REASONS FOR USING DIGITAL IMAGES
It is the most widely used medium being used today.
This field is expected to continually grow as computer graphics power also grows.
Many programs are available to apply steganography.
Steganographic Message
Steganographic Message has three parts:
Container or carrier
Hidden message
Steganography key
LSB METHOD
Replaces least significant bits with the message to be encoded.
Most popular technique when dealing with images.
Simple, but susceptible to lossy compression.
LSB-Example
Host Pixel: 10110001 Host Pixel: 10110011
Secret Pixel: 00111111 Bits used: 4
New Image Pixel: 10110011 New Image: 00110000
Tools for Steganography
Hide and Seek (versions 4.1 and 5.0)
StegoDos
Steganos is a LSB embedding system.
References
M. D. Swanson, B. Zhu and A. H. Tewfik, “Robust Data Hiding for Images”, IEEE Digital Signal Processing Workshop, pp. 37-40, Department of Electrical Engineering, 1996.
R. Hipschman, The Secret Language, Exploratorium, http://www.exploratorium.edu/ronh/secret/secret.html, 1995
S. Cacciaguerra and S. Ferretti, “Data Hiding: Steganography And Copyright Marking”, Department of Computer Science, University of Bologna, http://www.cs.unibo.it/people/phd-studen...hiding.pdf