27-02-2013, 12:50 PM
A Short Survey on Image Steganography and Steganalysis Techniques
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Abstract
The paper describes a short survey on different types of
steganography techniques for image in spatial and transform
domains and steganalysis techniques for the detection of secret
message in the image. The strong and weak points of these
techniques are mentioned briefly so that researchers who work
in steganography and steganalysis gain prior knowledge in
designing these techniques and their variants. One can develop a
better steganography technique by analyzing the contemporary
steganalysis techniques.
INTRODUCTION
With advancements in digital communication technology
and the growth of computer power and storage, the
difficulties in ensuring individuals' privacy become
increasingly challenging. The degrees to which individuals
appreciate privacy differ from one person to another. Various
methods have been investigated and developed to protect
personal privacy. Encryption is probably the most obvious
one, and then comes steganography. Encryption lends itself to
noise and is generally observed while steganography is not
observable. The term steganography refers to the art of covert
communications [1]. Steganography's aim is to make the
secret communication undetectable, that is, to hide the
presence of the secret message. It modifies the carrier in an
imperceptible way only so that it reveals nothing neither the
embedding of a message nor the embedded message itself.
The recent development of the Internet has brought new
attention to steganography.
TYPES OF STEGANOGRAPHY
Steganography can be either spatial or transform domain.
In general, steganographic algorithms rely on the replacement
of some noise component of a digital object with a pseudorandom
secret message [3]. In spatial domain methods, a
steganographer modifies the secret data and the cover
medium in the spatial domain, which involves encoding at the
level of the least significance bits (LSBs). To the human eye,
changes in the value of the LSB are imperceptible, thus
making it an ideal place for hiding information without any
perceptual change in the cover object. It is seen that
embedding in the higher LSB generates more visual
distortion to the cover image as the hidden information is
seen as "non-natural". Although LSB embedding methods
hide data in such a way that human does not perceive it, these
embeddings often can be easily destroyed. As LSB
embedding takes place on noise, it is likely to be modified,
and destroyed, by further compression, filtering, or a less than
perfect format or size conversion. Hence, it is often necessary
to employ sophisticated techniques to improve embedding
reliability.
CONCLUSION
The paper describes a short survey on different types of
steganography techniques for image in spatial and transform
domains and steganalysis techniques for the detection of
secret message in the image in spatial domain. The strong and
weak points of these techniques are mentioned briefly so that
researches who work in steganography and steganalysis gain
prior knowledge in designing these techniques and their
variants. The next plan is to develop a steganography
technique that is robust to different types of attacks and the
majority of contemporary staganlysis techniques fail to detect
the presence of secret messages.