08-09-2014, 02:04 PM
INFORMATION HIDING USING STEGANOGRAPHY
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ABSTRACT
The Internet as a whole does not use secure links, thus information in transit may be
vulnerable to interception as well. The important of reducing a chance of the
information being detected during the transmission is being an issue now days. Some
solution to be discussed is how to passing information in a manner that the very
existence of the message is unknown in order to repel attention of the potential
attacker. Besides hiding data for confidentiality, this approach of information hiding
can be extended to copyright protection for digital media. In this research, we clarify
what steganography is, the definition, the importance as well as the technique used in
implementing steganography. We focus on the Least Significant Bit (LSB) technique
in hiding messages in an image. The system enhanced the LSB technique by
randomly dispersing the bits of the message in the image and thus making it harder for
unauthorized people to extract the original message.
Introduction
One of the reasons that intruders can be successful is that most of the information they
acquire from a system is in a form that they can read and comprehend. Intruders may
reveal the information to others, modify it to misrepresent an individual or
organization, or use it to launch an attack. One solution to this problem is, through the
use of steganography. Steganography is a technique of hiding information in digital
media. In contrast to cryptography, it is not to keep others from knowing the hidden
information but it is to keep others from thinking that the information even exists.
Background of the Problem
Steganography become more important as more people join the cyberspace
revolution. Steganography is the art of concealing information in ways that prevent
the detection of hidden messages. Steganography include an array of secret
communication methods that hide the message from being seen or discovered
INFORMATION HIDING USING STEGANOGRAPHY
Introduction
Due to advances in ICT, most of information is kept electronically. Consequently, the
security of information has become a fundamental issue. Besides cryptography,
steganography can be employed to secure information. Steganography is a technique
of hiding information in digital media. In contrast to cryptography, the message or
encrypted message is embedded in a digital host before passing it through the
network, thus the existence of the message is unknown. Besides hiding data for
confidentiality, this approach of information hiding can be extended to copyright
protection for digital media: audio, video, and images
Overview Steganography
The word steganography comes from the Greek Steganos, which mean
covered or secret and –graphy mean writing or drawing. Therefore, steganography
means, literally, covered writing. Steganography is the art and science of hiding
information such that its presence cannot be detected [7] and a communication is
happening [8, 17]. A secret information is encoding in a manner such that the very
existence of the information is concealed. Paired with existing communication
methods, steganography can be used to carry out hidden exchanges.
Steganography vs. Cryptography
Basically, the purpose of cryptography and steganography is to provide secret
communication. However, steganography is not the same as cryptography.
Cryptography hides the contents of a secret message from a malicious people,
whereas steganography even conceals the existence of the message. Steganography
must not be confused with cryptography, where we transform the message so as to
make it meaning obscure to a malicious people who intercept it. Therefore, the
definition of breaking the system is different [6]. In cryptography, the system is
broken when the attacker can read the secret message. Breaking a steganographic
system need the attacker to detect that steganography has been used and he is able to
read the embedded message.
Steganography Applications
There are many applications for digital steganography of image, including
copyright protection, feature tagging, and secret communication [1,2]. Copyright
notice or watermark can embedded inside an image to identify it as intellectual
property. If someone attempts to use this image without permission, we can prove by
extracting the watermark.
STEGANOGRAPHY: RANDOM LSB INSERTION USING DISCRETE LOGARITHM
Introduction
Due to advances in ICT, most of information are kept electronically. Consequently,
the security of information has become a fundamental issue to provide confidentiality
and protecting the copyright for digital media such as audio, video, and images.
Therefore, the steganography is applied to hide some information in digital media,
whereby the message is embedded in a digital media. In this paper, we proposed the
Secure Information Hiding System (SIHS) that is based on Least Significant Bit (LSB)
technique in hiding messages in an image. The system enhanced the LSB technique
by randomly dispersing the bits of the message in the image and thus making it harder
for unauthorized people to extract the original message. Discrete logarithm calculation
technique is used for determining the location of the image pixels to embed the
message. The proposed algorithm provides a stego-key that will be used during the
embedding and extracting of the message.
Overview of Steganography
The word steganography comes from the Greek Steganos, which means covered or
secret and –graphy means writing or drawing. Therefore, steganography means,
accurately, covered writing. Steganography is the art and science of hiding
information such that its presence cannot be detected [1]. Secret information is
encoded in a way such that the very existence of the information is concealed in a
human perceptible.
The main goal of steganography is to communicate securely in a completely
undetectable manner [15] and to avoid drawing suspicion to the transmission of a
hidden data [8]. Therefore, in existing communication methods, steganography can be
used to carry out hidden exchanges. The idea of steganography is to keep others from
thinking that the information even exists and not to keep others from knowing the
hidden information. If a steganography method causes anybody to suspect there is a
secret information in a carrier medium, then the method has failed [2].
Discrete Logarithm
Discrete logarithm calculation can be used to solve sequence-mapping problem. The
main idea here is to generate random numbers without any repetition. With this set of
random numbers, a random-mapping can be done.
Briefly, we defined discrete logarithm in the following way to produce random
numbers. First, we defined a primitive root of a prime number p as one whose powers
generate all the integers from 1 to (p – 1). That is, if a is a primitive root of the prime
number p, then the numbers
a mod p, a
2
mod p, …, a p-1
mod p
Analysis of SIHS
For the system analysis, we presented three cases. In all cases the testing are done
through the normal viewing of the human eyes. As mentioned before, this system has
been developed to overcome a sequence-mapping problem when using LSB. A GIF
image with 200x200 in size and a message of 1 KB as shown in Figure 3.3 and Figure
3.4, respectively, have been chosen to test the technique.
Basic LSB with sequence-mapping
However by using discrete logarithm calculation, the problem of sequence-mapping
can be solved. Figure 3.8 illustrates a message embedded using random-mapping
technique. In this technique, the selected pixel for embedding the message bits
depends on the random number generated by the SIHS and a key, k. Although the
third party could determine where the message bits are embedded, he has a difficulty
to recover it because the message bits are embedded in a random order. The
recovered message will be a nonsense symbols as shown in Figure 3.7.
CONCLUSION
Steganography can be used for hidden communication. We have explored the limits of
steganography theory and practice. We pointed out the enhancement of the image
steganographic system using LSB approach to provide a means of secure
communication. A stego-key has been applied to the system during embedment of the
message into the cover-image. In our proposed approach, the message bits are
embedded randomly into the cover-image pixels instead of sequentially. Finally, we
have shown that steganography that uses a key has a better security than non-key
steganography. This is so because without the knowledge of the valid key, it is
difficult for a third party or malicious people to recover the embedded message.
However there are still some issues need to be tackled to implement LSB on a digital
image as a cover-object using random pixels