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DIGITAL STEGANOGRAPHY
ABSTRACT
rough
any number of processes that will hide
term
a message within an object, where the
Steganography is secret writing) has
hidden message will not be apparent to
been used in various forms for 2500
an observer. This paper will explore
years. Steganography is the art and
steganography
science of hiding information by
instances
embedding messages within other,
application.Finally, future projections
seemingly harmless messages. It has
on
found use in variously in military,
technique are made, along with few
diplomatic, personal and intellectual
explanations using our own software
property applications. Briefly stated,
and programs.
Greek
Steganography
(a
translation
the
of
this
from
through
perfect
its
earliest
potential
file
future
encryption
steganography is the term applied to
INTRODUCTION
. A rough translation of the Latin title
What is Steganography:
is: “Steganography: the art through
which writing is hidden requiring
Steganography literally means covered
recovery by the minds of men.”
writing or hidden writing i.e., writing
Although people have hidden secrets in
that is known to casual observer, is
plain
derived from Greek words ‘steganos’
sight—now
called
steganography—throughout the ages,
meaning
covered
or
secret
and
the recent growth in computational
‘graphy’ meaning writing or drawing.
power and technology has propelled it
This technique
to the forefront of today’s security
of secure and secret communication
techniques.
that conceal the existence of secret
includes all methods
messageToday the field attains new
dimensions with the advent of digital
computer.
Steganographic software enables
sound files.
information to be hidden in graphics,
SECRET
COMUNICATION METHODS
The secret communications
there are different ways of hiding
methods are invisible dots, microdots,
writing between the lines of an
character
than
ordinary letter. The text or picture that
cryptographic methods of permutation
you drew would only appear if you
and substitution), digital signatures,
colored over the written area with a
covert channels and spread-spectrum
special marker The common form of
signals. It’s also notoriously known
invisible writing is through the use of
arrangement
(other
that
invisible inks whose sources are milk,
vinegar, fruit juices and urine. These
darken when heated and they are easy
to decode.
IMPLEMENTATION OF
STEGANOGRAPHY
There are ways to hide information
the human inability to distinguish
in an image, audio and even text files.
negligible changes in image color or
Computer steganography is based on
sound quality, which is especially easy
two principles. The first one is that the
to make use of in objects that contain
files that contain digitized images or
redundant information, be it 16-bit
sound can be altered to a certain extend
sound, 8-bit or even better 24-bit
without loosing their functionality
image.. Steganography allows you to
unlike other types of data that have to
hide information in five innocent
be exact in order to function properly,
looking files types: JPEG, PNG, BMP,
an example of that would be a
HTML
computer program.
If one step is missed or
overlooked you cannot continue the
process. The other principle deals with
and
WAV.
TYPES OF
types, these are Fragile and Robust.
STEGANOGRAPHY

Fragile
which
Fragile
cannot
easily
be
involves
destroyed. Although no mark is
embedding information into a
truly indestructible, a system
file which is destroyed if the
can be considered robust if the
file is modified. This method is
amount of changes required to
unsuitable for recording the
remove the mark would render
copyright holder of the file
the file useless. There are two
since it can be so easily
main types of robust marking:
removed, but is useful in
Fingerprinting
situations where it is important
marking.
steganography

–
Steganography can be split into two
and
Water
Robust – Robust marking aims
to embed information into a file
Text Techniques
is an original or a copied version.
Hiding information is to conceal it in
Figure shows the general principle in
what seems to be inconspicuous text. It
embedding hidden information inside a
is more difficult when it comes to
document. The codebook is a set of
electronic versions of text. Copies are
rules that tells the encoder which parts
identical and it is impossible to tell if it
of the document it needs to change.
Codebook
Encoder
Original
Document
Marked Documents
Image Techniques

LSB – Least Significant Bit
way of hiding information in an
Hiding (Image Hiding) –This
image and yet it is surprisingly
method is probably the easiest
effective. It works by using the
least significant bits of each
most significant bits of another.
pixel in one image to hide the
Audio Techniques

Spread
Spectrum
—
the surge of mobile phones, which
spread
play MIDI ring tones.
spectrum systems encode data as a
binary sequence which sounds like



MP3 — The MP3 format is
noise but which can be recognised
probably the most widespread
by a receiver with the correct key.
compression format currently used
MIDI — MIDI files are good
for music files. Due to this, it also
places to hide information due to
happens to be very good for hiding
the revival this format has had with
information in
Video — For video, a combination
files for the video (consisting of
of sound and image techniques can
many images) and the sound. So
be used. This is due to the fact that
techniques can be applied in both
video generally has separate inner
areas to hide data.
Limitations
There are limitations on the
useful the message should be hidden
use of steganography due to the size of
without any major changes to the
the medium being used to hide the
object it is being embedded in. This
data. In order for steganography to be
leaves limited room to embed a
message without noticeably changing
many of the obvious candidates for
the original object. This is most
embedding data are lost
obvious in compressed files where
.Advantages
Attempting to detect the use of
infallible. But it considerably
steganography is called Steganalysis
increases the work of any
(the task of detecting and possibly
experienced code-breaker, who must
disabling steganographic information)
identify first the right carrier, extract
and can be either passive, where the
the sensitive data from it, and only
presence of the hidden data is detected,
after that (if he gets this far) – the hard
or active, where an attempt is made to
work of breaking the code
retrieve the hidden data it is not
CONCLUSION
Steganography is a dynamic
believe it will be used more often in
tool with a long history and the
the
capability to adapt to new levels of
communication
technology. It has its own place in
concealment. Security professionals
computer data security. By the amount
will surely need to be aware of its
of free and commercial tools available
existence as its use becomes more
today, one can deduce that the use of
prevalent. Hiding a message with
steganography
steganography methods reduces the
is
growing.
Steganography is just another tool for
someone to use to hide data, and I
REFERENCES
http://www.jjtc.com
http://www.stegoarchive.com
http://www.forensics.nl/steganog
raphy
future,
whether
or
for
personal
covert
data
chance of a message being detected.