1. science
2. computer science
3. cryptography

IPASJ International Journal of Computer Science (IIJCS)
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Volume 3, Issue 4, April 2015
A REVIEW ON: SECURITY ENHANCEMENT
OF PAYLOAD OBJECT
1
Anushka Nagpal, 2 Deepak Bagga
Haryana Engg. College (Jagadhri)
ABSTRACT
With the rise of internet most of the communication & information sharing is done over the web. The increasing unauthorized
access of confidential data, information security is most important. Thus a big issue is to reduce the chances of information
detection during transmission. Steganography is a process that involves hiding message in an appropriate carrier for example an
image. The carrier can be sent to receiver without anyone else knowing that it contain a hidden message. The initial aim of
steganography is how it is implemented. The objective of this review paper is to study various steganography techniques for
embedding the message and to communicate secretly using open channel.
Keywords: least significant bit , discrete cosine transform, stego-object, payload, PSNR.
1. INTRODUCTION
Digital data communication is an essential part of everyone’s life. Data communication has some problems such as internet
security so to avoid these problems, cryptography is among one of the methods. However, encryption results in a disordered
and confusing message and can attract eavesdroppers easily. The technique used to keep the contents of a message secret is
called steganography. Steganography methods overcome this problem by hiding the secret information behind a cover
media (video, audio or image) because the presence of information cannot be noticed by any attacker. The goal of
steganography is to keep the existence of a message secret [15].
Steganography is concealed writing. The word steganos means “covered” and graphial means “writing”[1] and is the
technique of hiding secret data within a cover media such that it does not draw the attention of an unauthorized person [5].
In ancient times, the data was protected by hiding it on the stomach of rabbits, on the scalp of the slaves. But today’s most
of the people transmit the data in the form of text, image, video and audio over the medium . So, in order to transmit
confidential data safely, the multimedia object like audio, video, images are used as cover medium to hide data.
Using steganography, it embed a secret message inside a piece of unsuspicious information i.e cover object, this cover object
with object secretly embedded message is called stego-object [16] and send it without anyone knowing of the existence of
the secret message. Cryptography and steganography techniques are closely related where Cryptography scrambles the
message so that they cannot be understood. Steganography will hide the message so there is no knowledge of the existence
of the message in the very first place. So, both sciences can be combined to produce better protection of the message. Even,
when the steganography fails and the message is detected, it is still of no use as it is encrypted using cryptography
techniques[20]
Cover File
(Image, Video,
Audio)
Data to hide
(Text, Image,
Video, Audio)
Steganography
Stego File
Fig a: The Process of hiding Data
THE BASICS FOR EMBEDDING
The first step in embedding for hiding information is to pass both the secret message and the cover medium into the
encoder. Inside the encoder, several protocols will be implemented to embed the secret information into the cover medium.
The type of protocol will depend on what kind of information you are trying to embed. For example, an image protocol to
embed information inside images is being used.
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In embedding process, a key is often needed This can be in the form of public or private key so you can encode the secret
message with your private key and the recipient can decode it using your public key. In this way, it reduces the chance of a
third party attacker getting hold of the stego object and decoding it to find out the secret information.
Fig b: Generic form of image steganography
After passing through the encoder, a stego object will be produced. A stego object is the original cover object with the secret
information embedded inside it. This object should look almost identical to the cover object otherwise a third party attacker
can see embedded information. Having produced the stego-object, it will then be sent off via some communication channel,
such as email, to the intended recipient for decoding it. The recipient must decode the stego object in order to view the
secret information. At last, the decoding process is reverse of the encoding process. It is simply the extraction of secret data
from a stego object.
Reasons for rapid growth of interest in steganography:
1.) Restrictions imposed on the availability of encryption service by various governments have encouraged people to take
a move towards the methods through which messages can be embedded in cover sources.
2.) Publishing and broadcasting industries have become interested in techniques for hiding encrypted copyright marks
and serial numbers in digital films, audio recordings, books and multimedia product.
IMAGE STEGANOGRAPHY TECHNIQUES
Steganography in images are classified into two categories: Spatial-domain based Steganography and the Transform domain
based Steganography.
IMAGE STEGANOGRAPHY
SPATIAL
DOMAIN
TRANSFORM
DOMAIN
1. SPATIAL DOMAIN METHOD
In spatial domain scheme, the secret messages are embedded directly i.e processing is applied directly on the pixel values of the
image. In this, the simplest Steganography method used is the least significant bits (LSB) insertion technique. In LSB technique,
least significant bits of the pixels are replaced by the message bits.[7].
2. TRANSFORM DOMAIN METHOD
The transform domain Steganography technique is used for hiding a large amount of data and also provides a good
invisibility of data and no loss of the secret message. In this technique firstly, pixel values are transformed and then
processing is applied on the transformed coefficients. DCT & DWT techniques which are implemented in transform
domain. They transform digital image data from spatial to the transform domain. In DCT, after transforming the image in
transform domain, then the data is embedded in the least significant bits of the medium frequency components, it is a lossy
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Volume 3, Issue 4, April 2015
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compression [8]. In DWT, secret messages are embedded in high frequency coefficients and it provides maximum
robustness.
FACTORS THAT AFFECTS A STEGANOGRAPHIC METHOD:
Here are some factors that determines how efficient and powerful a technique is are as follows[19]:
a)Invisibility or statistical undecteability (imperceptibility) of data : Human eyes cannot distinguish the difference
between original and stego image.
b) Capacity: maximum information that can safely be embedded.
c) Robustness:The amount of modification the stego medium can withstand before an adversary can destroy hidden
information
d) PSNR (Peak Signal to Noise Ratio): It is defined as the ratio between the maximum possible power ofa signal and the
power of corrupting noise that affects the fidelity of its representation [10,11]. This ratio is often used for image quality
measurement between the original image and a compressed image. The higher the PSNR,the better is the quality of the
compressed image. PSNR is measured in decibels.
e) MSE (Mean Square Error): It is the average squared difference between a reference image and a distorted image. An
Image steganography technique is efficient if it gives a low MSE. It is calculated or computed pixel-by-pixel by adding
up the squared differences of all the pixels and dividing by the total pixel count [12].
2. RELATED WORK
Stuti Goel et.al This paper deals with hiding text in an image file using Least Significant Bit (LSB) based Steganography,
Discrete Cosine Transform (DCT) based Steganography and Discrete Wavelet Transform (DWT) based steganography.The
LSB substitution algorithm is implemented in spatial domain, in this the payload bits are embedded into the least significant
bits of cover image to produce the stego-image whereas in DCT & DWT algorithm are implemented in frequency domain in
which the stego-image is transformed from spatial domain to the frequency domain and in this the payload bits are
embedded into the frequency components of the cover image. Then the performance and comparison of these three
techniques is evaluated on the basis of these parameters PSNR, MSE, Capacity & Robustness.[9]
G.Arun Karthick et.al this paper represents a new scheme which is hybrid in nature, it combines two distinct domains
1)Steganography(Combination of Image + cryptography) .
2) Image Fusion – Fusing two images.
Steganography embeds the digital data message along with the media file where digital data may be text, image or hybrid.
Although both Cryptography and steganography techniques are combined to provide security in some criteria yet advanced
system of security is needed to share information without any interference. To overcome the real world problem, they
proposed a novel algorithm called StegFuse where cryptography and steganography is applied on two various types of
images, and then after applying steganographic technique both of these images are subjected to image fusion so as to get the
fused image. Wavelet transform technique is applied on both the image during fusion.
Prof.S.V.Kamble et.al This paper reviews stegnography based on digital image.Various Concepts and priniciple of
steganography is illustrated. Different embedding techniques such as LSB ,DCT, Huffman encoding [6], DWT embedding
method are generalized in this paper . Then the performance and specification of image steganography is discussed at last .
In An image based steganography that combines LSB, DCT, and compression techniques on the image to enhance the
security of the payload object.
Sneha Arora et.al (May2013) This paper proposed a new technique for the image steganography using edge detection
method for RGB images. There are many algorithms to hide data with precision level but they are also decreasing the
quality of the image. In this proposed study, the edges of an RGB image will be detected by scanning method using a 3x3
window, and then text will be embedded in to the edges of the color image. So by doing this not only high embedding
capacity will be achieved,but it also enhances the quality of the stego image from the HVS (human vision system).
Gowtham Dhanarasi et.al A block complexity analysis for transform domain image stegonagraphy is done in this paper.
The algorithm proposed here works on the wavelet transform coefficients which embed the secret data into the original
image. The technique implemented here is capable of producing a secret-embedded image that is indistinguishable from the
original image and to human eye. So this can be achieved by retaining the integrity of the wavelet coefficients at high
capacity embedding technique. This improvement to capacity-quality trading–off interrelation is analyzed in done in
detailed.
H.B.Kekre et.al(June2014) In this paper the author has proposed a Hybrid Approach so as to secure digital images. The
proposed framework introduced is a combination of Information Hiding and Image Encryption. For Information Hiding,
four different methods of Multiple LSB’s Algorithm are used in this paper and then they are evaluated. A number of
parameters are also used to evaluate the performance of the proposed framework. At last Experimental results show a good
performance.
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Inderjeet Kaur et .al The technique proposed is a combination of steganography and watermarking (TDSSW)which
provides copyright protection to the information being transmitted secretly over communication channel. The proposed
technique is a transform domain based technique. At end it was observed that the proposed technique comes up with good
PSNR (Peak Signal to Noise Ratio) value and enhanced Security.
S.Shanmugasundaram(March2014)
This proposed method here uses both Cryptography and Steganography to enhance the security of the message or payload.
Firstly, the secret message is encrypted using a RSA algorithm and then it is randomized using OAEP. After that this
encoded message is embedded in the bitmap cover image using frequency domain approach. So for embedding the
encrypted message, they initially used skin tone regions of the cover image are taken and then they are detected by using
HSV (Hue, Saturation, Value) model. Thereafter, a region from skin detected area is selected, which is called as cropped
region. In this the cropped region of secret message is embedded using DD-DWT (Double Density Discrete Wavelet
Transform). DD-DWT overcomes the shortcomings of DWT (like poor directional selectivity, Shift invariance, oscillations
and aliasing). Hence the image obtained after embedding secret message(i.e. Stego-image) is far more secure and it has an
acceptable range of PSNR. The terms of PSNR and robustness against various noises like (Poisson, Gaussian, salt and
pepper, translation, rotation etc.).
Johri and Asthana[13] They proposed a steganography technique in which the data is embedded using alteration
component technique. After that the, key and secret message will replace each pixel. Then for the security of stego-image
palette based image technique is applied by stretching process. At the receiver end, the receiver having the same secret key
applies destretching palette process on stego-image using alteration component extraction process to extract the data. This
technique used has higher capacity and better imperceptibility.
Swati and Mahajan [14] This paper proposed a secure image steganographic model by using RSA algorithm and LSB
substitution. In this method, firstly the secret data is encrypted using recipient’s RSA public key. After that each bit of the
encrypted message is inserted to the LSBs of image in different images so as to get the best cover image. The Best cover
image is the one that requires minimum number of LSB changes. When the receiver receives the stego-image it will extract
the message in the encrypted form and then it will decrypt it using its private key.
Subba Rao et al. [17] This paper presented an image steganography technique which randomizes the sequence of cipher
bits. Then they computed the suitability measure of various random sequences of the cipher bits against a given image and
select the random sequence closest to the image. After that they generated those random sequences by using L.F.S.R. They
then embed these random sequences of cipher bits into the image.
Velagalapalli et al. [18] This paper proposed a technique which is known as SteganPEG to hide data in jpeg images.
Performs JPEG compression on the data to be hidden. The method also uses a
new cryptography technique which is
known as ‘Rotatocrypt’ to encrypt or decrypts data using rotations. A list called ‘PassStore’ is created from the password
used. Later, encryption is done by right rotating the bits as guided by the value in PassStore.
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3.CONCLUSION
Ensuring data security is a big challenge for computer users. Businessmen, professionals, and home users all have some
important data that they want to secure from others. The ultimate aim of steganography is to hide the existence of message
in the cover medium. This paper, provides an overview on Steganography. Various embedding techniques on an image
steganography such as LSB in spatial domain, DCT & DWT in transform domain are discussed. The strength of the
steganographic technique depends mainly on three factors - robustness, imperceptibility level in the stego image, and
embedding capacity. This paper also provides a comparative table drawn from the literature.
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ISSN 2321-5992
[16]. Jagvinder Kaur and Sanjeev Kumar, ” Study and Analysis of Various Image Steganography Techniques” IJCST Vol.2,
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