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Applying and Analyzing Security using Images : Steganography v.s. Steganalysis

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Applying and Analyzing Security using Images : Steganography v.s. Steganalysis Powered By Docstoc
					                                                            (IJCSIS) International Journal of Computer Science and Information Security,
                                                            Vol. 9, No. 4, April 2011




           Applying and Analyzing Security using Images
                                              Steganography v.s. Steganalysis


                         Nighat Mir                                                   Asrar Qadi[2], Wissal Dandachi[2]
                 Computer Science Department                                           Computer Science Department
                       Effat University                                                       Effat University
                     Jeddah, Saudi Arabia                                                  Jeddah, Saudi Arabia
                   nighat_mir@hotmail.com                                        aqadi@effat.edu.sa, wdandachi@effat.edu.sa


Abstract                                                                     However, cryptography does not prevent the challenger
                                                                             from disturbing the communication channel between the
Steganography is an art of hiding a message in such a way that               two parties, thereby preventing any further communication.
anyone is unaware of the message’s presence. It is an Image                  Steganography attempts to hide the very fact that any two
processing technique used for hiding information and challenges              parties are conducting a private communication. An
an eavesdropper to break into a message. Steganography is a                  adversary may know that the two parties are
Greek work which means “covered writing”. Steganalysis in                    communicating, but this communication appears to the third
opposite is a technique used to real the hidden messages. Cover
                                                                             party to be a benign communication with no covert subtext.
images are used to embed information which results as stego
images are further introduced on a communication channel for a
                                                                             [2]
secret conversation between parties. There are some                              Steganography uses stego-objects to hide or embed the
characteristics in images that must be analyzed to lead us to the            data into a cover image. Main purpose of Steganography is
existence of a hidden message and identify where to look for the             to guarantee no comprehension that a secret communication
hidden information. Steganalysis is used to analyze if a secret              is taking place by looking at the cover medium. It aims at
communication is taking place through images. There are                      hiding data (text, image, audio, video etc.) in such a way
different tools for applying and analyzing security using images.
                                                                             that there is no indication of the hidden message. This is
In this paper Steganography and Steganalysis both techniques
                                                                             achieved by using a cover file and an embedding file. The
have been practiced and analyzed on images using xiao tool. The
xiao tool also has built-in cryptographic algorithms, which adds
                                                                             term “cover” is used to describe the original data and the
another layer of security.                                                   information to be hidden in the cover data is called
                                                                             “embedded” data. The “stego” contains both cover and
    Keywords-     Steganography;   Steganalysis;   cryptography;             embedded data.
security; xiao                                                                   The most prevalent cover objects in use are digital
                                                                             images because of their potential payload [3]. A usual
           I.    INTRODUCTION (DIFFERENT TCHNIQUES)                          digital image of 640x480 pixels can hide approximately 300
    There are different methods for information security.                    KB and a high resolution image can approximately hide 2.3
Steganograohy and cryptography are two popular                               MB data. Various compression algorithms are available but
techniques but have different behavior.                                      the three most common are BMP, GIF and JPEG. In our
                                                                             system we have used BMP images as the selected tools only
    To control access to content a traditional approach is by                support this type of compression and we have also preferred
using cryptography, in which first data is encoded with a                    this tool over other available tools as it supports BMP and
standard compressor and then to perform full encryption of                   GIF which offers lossless compression.
the compressed bit stream with a standard cipher (DES,
AES, IDEA, RSA etc.) [1]. A data that can be read and                           There are many examples of Steganography systems
understood without any special measures is called plaintext                  which are generally available to hide the data or information
and when is encrypted into an understandable form is called                  in images i.e. Jsteg, JPhide-works on JPEG and GIF,
cipher text. The method of converting plaintext into cipher                  SecureEngine-hides information in BMP, GIF, HTM, and
text is called encryption. The encrypted message is useless                  TXT files.
for everyone except the person who has the decryption key                         The main objective of steganography is to converse
and algorithm. The process of reverting cipher text to its                   securely in a completely undetectable manner [4] and to
original plaintext is called decryption.                                     avoid depiction suspicion to the transmission of a hidden
    Steganography differs from cryptography. Cryptography                    data [5]. It is not to keep others from knowing the hidden
attempts to prevent a message between two parties being                      information, but it is to keep others from thinking that the
decoded by a third party who has intercepted the message.                    information even exists. If a steganography method causes




                                                                     100                               http://sites.google.com/site/ijcsis/
                                                                                                       ISSN 1947-5500
                                                             (IJCSIS) International Journal of Computer Science and Information Security,
                                                             Vol. 9, No. 4, April 2011




someone to suspect the carrier medium, then the method has                    choosing a tool to perform Steganography and the tool that
failed [6].                                                                   perform Steganalysis. There are many free tools available
                                                                              on the Internet to perform steganography and Steganalysis.
   Steganalysis is a science to detect whether a given                        Listed below are few which have tested and analyzed before
medium has hidden message in it. It includes the discovery                    finalizing the tool which we have used to perform
and destruction of hidden information [1]. Attacks and                        experiments.
analysis on hidden information may take several detecting
forms i.e. detecting, extracting, disabling or destroying                           http://www.jjtc.com/Steganography/tools.html
hidden information. An attacker may also embed false or
counter information into the hidden image.                                          http://www.jjtc.com/Steganalysis/

    It is possible to create a stego image that is not easy to                      http://xiao-steganography.en.softonic.com/
percept with a careful selection of an appropriate cover                            http://www.dound.com/Progs/Steg.htm
image and a good stego tool. The Majority of stego-images
do not expose visual clues. Once a stego image has been                              In the studied methodology an existing tool (xiao) is
discovered then several attacks can be taken to disable or                    used for applying and analyzing security using images for
destroy the hidden message. Determining a secret message                      different types of input data which consists of a text, image,
is an initial step in steganalysis and is considered as an                    and audio and in video formats. One of the reasons to select
attack on the hidden information. Second step toward                          this tool was based on the fact that it can apply both of the
steganalysis is to temper the stego image.                                    functions; embedding and extraction. xiao tool is used to
                                                                              apply steganography to secure data using different
    Security, Capacity and Robustness are three important                     cryptographic and hashing algorithms (RC2, RC4, DES, 3-
characteristics of information hiding systems. A lot of                       DES, MD2, MD4, MD5 and SHA) and it hides information
research has recently focused on using images as a cover for                  into a bitmap image BMP. This tool also supports
transferring covert messages [7].          Security through                   Steganalysis to analyze the hidden information on the
obscurity is one of the most trivial types of Steganographic                  bitmap images BMP and results into the original image and
algorithms. It is called so because the main idea is making                   the hidden file of above mentioned types.
warden impossible to understand if some communication
exists by embedding the data in the unexpected places.                            Xiao Steganography runs on Windows OS and we have
                                                                              experimented Version 2.6.01 for our system. It is a user
    Capacity refers to the amount of information surrounded                   friendly tool to encode a text, audio, video and image into a
in the cover file; for the security, it refers to the inability of            Bitmap file. User can follow the steps to perform the
a third-party to detect hidden information[7].Robustness is                   following; click on add file load the target file, embed secret
hiding the location of presence of the hidden information by                  message, then choose on the cryptographic or hash
creating an information channel with a small bandwidth in a                   algorithms and type a password for protection and then save
wide data stream.                                                             the stego file as a BMP file. We have presented our results
    Steganalysis technique that uses the Compression Bit                      in the form of pictures below, before and after applying the
Rate to detect the secret messages embedded into                              security aspects of the image processing. It is very hard to
images degrades quality [6]. The degradation process                          recognize and differentiate between the embedded and
is modeled as an optical distortion process that shows the                    original file and stands very well against visual perception.
document in a degraded state due to printing, photocopying,
and/or scanning. Mathematically, it is studied by calculating
the probability of flipped foreground/background pixels as
function of distance from the boundaries.
    Using        the compression bit       rate     quantitative
methodology, it will be able to predict the changes in the
image with the length of the embedded secret message with
the presence of noise imposed by the degradation process.
The methodology is based on that the fact that the entropy
of the stego signal is higher than the cover signal. Since
entropy is unpredictable, using a compression technique
could help to estimate the entropy signal, and as a result
statistically distinguish the steganalysis of the image [7].

                     II.    METHODOLOGY
                                                                                               Figure 1. General Block Diagram
    There are many tools available for Image Processing
techniques for different types of operating systems such as
Windows, Dos, Linux, Mac and UNIX. There are
differences in tools which should be considered while




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                                                                                                        ISSN 1947-5500
                                                      (IJCSIS) International Journal of Computer Science and Information Security,
                                                      Vol. 9, No. 4, April 2011




                     III.    PROPOSED SYSTEM                           A.1:        Steganalysis: Retrieving the hidden message
    Different types of multimedia type of data have been
used for the experiments and results. We have applied and
tested the methodology on following types of cover
medium:
     1.     Securing text in an image file
     2.     Securing an image in an image file
     3.     Securing an audio file in an image file
     4.     Securing a video file in an image file                     Figure 5. Cover Image (BMP) and Text file


A. Experimental Results 1:                                             B. Experimental Results 2:
    Applying, Steganography on an image for securing a                    Applying, Steganography on an image for securing an
text file.                                                             image file.




Figure 2. System Diagram to hide a text file
                                                                       Figure 6.   System Diagram to hide an image




                                                                       Figure 7. Cover Image (BMP) and Image file(JPG)


                                                                       B.1:        Steganalysis: Retrieving the hidden message

Figure 3.   BMP file Original image




                                                                       Figure 8. System Diagram to retrieve a hidden image


                                                                       C. Experimental Results 3:
                                                                       Applying, Steganography on an image for securing an
                                                                       Audio file.

Figure 4. BMP file with a hidden text file


A “text file” with a message along “There is a hidden
message” is embedded into the original image (figure 1)
and the resultant image is shown in figure 2 which reveals
no hidden information.
                                                                       Figure 9. System Diagram to hide an audio file




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                                                                                                   ISSN 1947-5500
                                                                (IJCSIS) International Journal of Computer Science and Information Security,
                                                                Vol. 9, No. 4, April 2011




Figure 10. Cover Image (BMP) and audio file(MIDI)


C.1:       Steganalysis: Retrieving the hidden message




Figure 11. System Diagram to retrieve a hidden video file


D. Experimental Results 4:
Applying, Steganography on an image for securing a Video
file.


                                                                                 Figure 13. Histogram of Original Images( Fig. 3,4,5,7)




Figure 12. Resultant image where there is a hidden video file


                  IV.    COMPARATIVE ANALYSIS
    A comparison between the original and stego image was
made, details were checked by analyzing the graphs and
values of both images under gray level and colored level. It
has been noticed that the histogram (size, number of pixels,
median, and standard deviation) remained same in both
images; only a very minor change was noticed in the
fraction part of standard deviation which can be ignored.




                                                                                 Figure 14. Histogram of Stegoed Images




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                                                                                                              ISSN 1947-5500
                                                        (IJCSIS) International Journal of Computer Science and Information Security,
                                                        Vol. 9, No. 4, April 2011




                                                                         Figure 17. Histogram of Fig. 12
Figure 15. Histogram of Fig. 10




Figure 16. Histogram of Results of audio stegoed file                    Figure 18. Histogram of Results of video stegoed file




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                                                                                                     ISSN 1947-5500
                                                                    (IJCSIS) International Journal of Computer Science and Information Security,
                                                                    Vol. 9, No. 4, April 2011




                          V.     CONCLUSION                                          [2]   J. Clerk Maxwell, A Treatise on Electricity and Magnetism, 3rd ed.,
                                                                                           vol. 2. Oxford: Clarendon, pp.68–73, 1892
    Steganography is one of the most known methods of                                [3]   I. S. Jacobs and C. P. Bean, “Fine particles, thin films and exchang
hiding data. This technology is easy to use but difficult to                               anisotropy,” in Magnetism, vol. III, G. T. Rado and H. Suhl, Eds.
detect and this is one of the reasons to use it. The more you                              New York: Academic, pp. 271–350, 1963
use this technology the more you know about it and get                               [4]   Mohammad Shirali-Shahreza, “Text Steganography by Changing
used to it. There are many other reasons to use it, like using                             Words Spelling”, Feb. 17-20, 2008 ICACT 2008
it as cover medium key processes instead of using                                    [5]   R. Nicole, “Title of paper with only first word capitalized,” J. Name
passwords to protect you data.                                                             Stand. Abbrev., in press
                                                                                     [6]   Y. Yorozu, M. Hirano, K. Oka, and Y. Tagawa, “Electron
    In this research Steganography and Steganalysis have                                   spectroscopy studies on magneto-optical media and plastic substrate
been and studied and security parameters have been                                         interface,” IEEE Transl. J. Magn. Japan, vol. 2, pp. 740–741, August
analyzed using a tool xiao tool which has different built in                               1987 [Digests 9th Annual Conf. Magnetics Japan, p. 301, 1982
Cryptographic functions for adding security to the system.                           [7]   M. Young, The Technical Writer's Handbook. Mill Valley, CA
                                                                                           University Science, 1989
Different types of data types have been experimented to
achieve both Steganography and Steganalysis. The tool was
selected based on the reason that it supports both                                                         AUTHORS PROFILE
Steganography and Steganalysis in one. Later the results
and the resultant images were taken in to Photoshop to see                           Nighat Mir is a Computer Scince Lecturer in College of Engineering,
                                                                                          Effat University, Jeddah, Saudi Arabia
the graphical and detailed view of original and stegoed
images. Different histograms views were made for the                                 She is also Pursuing her PhD studies from Bryson University, USA. Her
                                                                                     subject of specialization is in Information Security using Text
images containing different types of data. Histograms were                           Watermarking and Text Steganography
noticed based on (size, number of pixels, median, and
standard deviation) and a very minute different between the                          Asrar Qadi is a Computer Science Graduate of Effat University for Fall
original image and the stegoed images was observed.                                  2010 session

                             REFERENCES                                              Wissal Dandachi is a Computer Science Graduate of Effat Univeristy for
                                                                                     Fall 2010 session
[1]   [1]. G. Eason, B. Noble, and I. N. Sneddon, “On certain integrals of
      Lipschitz-Hankel type involving products of Bessel functions,” Phil.
      Trans. Roy. Soc. London, vol. A247, pp. 529–551, April 1955




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