e-Security | Vol: 36-12014
© CyberSecurity Malaysia 2014 - All Rights Reserved
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1.0 Introduction
Nowadays, digital communication has become an essential part of our modern
infrastructure. A lot of applications are Internet-based and this situation demands
the security of data conidentiality and integrity so as to ensure that sensitive data
and information on the Internet is protected against unauthorised access. There are
various techniques that can be used to protect sensitive information. One of such
technique is by using steganography. Unlike cryptography, steganography is the
art of hiding and transmitting secret data. However, it is not intended to replace
cryptography but to compliment it. The goal of steganography is to hide sensitive
information in a cover so that no one can guess the existence of such information.
The message will be inserted into the cover by modifying the nonessential pixels of
the cover Amirtharajan et. al., 2010.
2.0 Steganography Techniques, Characteristics, And Types
In order to obtain security, there are many suitable steganographic techniques that
can be used. It depends on the type of the cover object Hussain and Hussain, 2013.
These known steganographic techniques are:
a. Image steganography: The image is used as the cover object and pixel
intensities are used to hide the information.
b. Audio Steganography: The audio is used as the carrier. It has become very
signiicant medium due to voice over IP VOIP popularity.
c. Network Steganography: The cover object is used as the network protocol
and protocol is used as carrier.
d. Video Steganography: The video is used as carrier for hidden information.
e. Text Steganography: Using general technique, such as number of tabs,
white spaces, capital letters, just like Morse code and etc.
Each technique embeds a message inside a cover. Various features characterise
the method’s strength and weaknesses. The importance of each feature depends
on the application. Al-Ani et. al. 2010 classiies steganography systems into ive
characteristics which are capacity, robustness, undetectable, invisibility, and security.
Basically, there are three types of steganography Al-Ani et. al., 2010.
a. Pure Steganography - does not
require prior exchange of some secret information before a particular
message is being sent. This type of steganography is more preferable for
most application. Figure 1 shows how Pure Steganography works.
A Review on Steganography Substitution System Methods
The recent development of new robust techniques has now caught the eye of the privacy-craving public.
By | Nor Azeala binti Mohd Yusof, Abdul Alif Zakaria, Hazlin Abdul Rani, Nik Azura Nik Abdullah