system of data hiding for secured transmission. [10] [11] The proposed ... The proposed RNS Model structure and the flow chart of its functionality have ... C. RNS Model: RNS model has .... Tata McGrawâHill, 2nd Edition. [9] Balagurusamy,. E.,.
Volume 2, Issue 3, March 2012
ISSN: 2277 128X
International Journal of Advanced Research in Computer Science and Software Engineering Research Paper Available online at: www.ijarcsse.com
Design and Implementation of RNS Model Based Steganographic Technique for Secured Transmission Rajdeep Chowdhury*
Nilanjan Dey
Department of Computer Application JIS College of Engineering Kalyani, West Bengal, India
Department of Information Technology JIS College of Engineering Kalyani, West Bengal, India
Saikat Ghosh Department of Computer Application JIS College of Engineering Kalyani, West Bengal, India
Abstract— Despite of modern findings in security mechanisms, a vast scope lies ahead of researchers to extend their innovative proposals in the field of network security, especially in the genre of cryptography. The formulation of the proposed technique lies with the essence of cryptography, in alliance with steganography, restoring the USP of the proposed technique. The proposed technique involves rich utilization of distinct secret keys, matrices and scripter. The concept of image hiding is an innovative tool adhered by the researchers to culminate the corresponding cipher text in the form of a stego image. An effective methodology of steganography incorporated in the paper, ensuring an addition to the technique using the formulated object in devising the flow of the model, coined as RNS Model, has been extensively attained. The paper highlights the concept of image hiding through the development of effective algorithm based on a proposed model, which can be quite effectively incorporated in business organizations to address the issues of data security. Keywords— Steganography, RNS Model, Append Key, Norm Key, Shift Key, Scripter, RNS Object, Stego Image.
I. INTRODUCTION Steganography [5] is a vastly accepted methodology in security mechanism [7] [8] [10] [11] and the proposed RNS Model based algorithm turns out to be a new and improved system of data hiding for secured transmission. [10] [11] The proposed technique turns out to be simple yet effective stepwise methodology that creates a cipher text powerful enough to avoid any unwanted cheap deciphering, during the retreat of the original text. [2] [11] The technique involves utilization of various secret keys at various steps of the proposed model, along with formulation of various matrices [3] and also the selective use of scripter. The proposed technique can be best explained as a ladder-step algorithm in which every step of the ladder shows operational functionality on the plain text, in the process of formulating the cipher text. The plain text is initially appended, then normalized [1], followed by series of conversions, shift operations and selective scripting, to be finally conjured up into formation of an object, termed as RNS object. The RNS object is used during the formation of the foreground image as well as the background image. The proposed steganographic technique is used to ensure the formation of the stego image, by application of Alpha factor on the formed images. [5] [6] The final output shows the background image hiding within the foreground image, coined as stego image. [4] [5]
II. THE SCHEME The Scheme basically comprises of three fragments, namely; Encryption technique, Decryption technique and RNS Model, exploring the intricacies of the proposed technique to the tee. The proposed RNS Model structure and the flow chart of its functionality have been detailed in the section. A. Encryption Technique Step 1: Plain Text is first converted into Hexadecimal Matrix. Step 2: Hexadecimal Matrix is appended with the Append Key to form the Character Matrix. Step 3: Normalization is performed on the Character Matrix to form a Re-map Matrix using the Norm Key. This is an iterative process where Normalization can be performed any number of time, depending on the Key Text. Step 4: The Re-map Matrix is then converted into its Binary equivalent. Step 5: Shift Operation is done using the Shift Key iteratively. Step 6: ASCII Equivalent of the Shift Matrix is retrieved. Step 7: The ASCII Matrix is scripted selectively to attain the Co-ordinate Matrix.
Volume 2, Issue 3, March 2012 Step 8:
The co-ordinates of the Co-ordinate Matrix are used to form the RNS Object, the final component in the proposed RNS Model. Step 9: Foreground Image and Background Image are formed from the RNS Object. Step 10: Alpha Factor is used to form a Stego Image using Steganographic technique. B. Decryption Technique: Step 10 to Step 1 is followed in the reverse order during the decryption technique and retrieval of the plain text.
www.ijarcsse.com The above mentioned factors when properly sequenced as per the devised model [Figure 1], gives rise to the encrypted code as well as the decrypted code. Example: A. Encryption Technique: Plain Text XPLORE Key Text wF+2x1,1+2yL+zA Where, w=Append Key, x=Norm Key, y=Shift Key and z= Scripter
C. RNS Model: RNS model has been coined in purpose, with the initial letters of the first name of the concerned authors, namely;
Step 1:
Rajdeep –> R, Nilanjan –> N and Saikat –> S.
Hexadecimal Conversion X
P
L
O
R
E
58
50
4C
4F
52
45
Step 2: Append Append ‗F‘ to each character 58 67
Step 3:
50 5F
4C 5B
4F 5E
52 61
45 54
Character Matrix Formation
Step 4:
Binary Conversion 67
1100111
5F 61 54 5B 5E
1011111 1100001 1010100 1011011 1011110
Figure 1 – RNS Model
Step 5: III. IMPLEMENTATION The working principle of the proposed technique mainly depends on few factors, namely; 1. Append Key, which appends a character 2. Norm Key, which normalizes the character matrix 3. Shift Key, which shifts the binary number k times 4. Scripter, selectively forms the co-ordinate matrix
© 2012, IJARCSSE All Rights Reserved
Shift Operation
In case after shifting, it is found out that unlike characters has the same binary string, then that particular character is shifted once again and marked with blue background and white body.
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Volume 2, Issue 3, March 2012
www.ijarcsse.com direction, then there can be multiple connections between the plotted points. To make the system less predictable, the path is provided but the image containing the path and the respective direction within the image containing the points is hidden. The image hiding technique comprises of two images, namely; Image–1 and Image–2. Foreground Image [Image–1]
Step 6:
ASCII Conversion 1111100
124
1110111
119
1111000
120
1110101
117
1110110
118
1111011
123 Figure 3 – Foreground Image
Step 7:
Selective Scripting
Background Image [Image–2]
E stands for even position, O stands for odd position and A stands for alternate position in the matrix. Here, scripter is a ―,‖ which is placed at the required place to form a coordinate matrix which finally provides the RNS Object.
12,4
Step 8:
1,19
12,0
1,17
11,8
1,23
RNS Object Formation Figure 4 – Background Image
Step 10:
Figure 2 – RNS Object
Step 9: RNS Object comprises of both points and connective paths. The paths denote the connectivity amongst the points in proper order, based on Selective Scripting. If the path is not furnished with their respective
© 2012, IJARCSSE All Rights Reserved
Forming Stego Image Using Alpha Factor
In order to vary the proportion of mixing of each image, Alpha Factor can be varied. Considering Alpha Factor to be equal to 0.5, the two images, namely; foreground image and background image are mixed equally. Considering Alpha Factor to be less than 0.5, the contribution of background image will be more. Considering Alpha Factor to be greater than 0.5, the contribution of foreground image will be more. With Alpha Value equal to 0.99, background image is fully hidden within foreground image, thereby conjuring up the formation of Stego Image
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Volume 2, Issue 3, March 2012
www.ijarcsse.com Step 4: Shift Back Operation
Step 5: Binary Value Retrieval Figure 5 – Stego Image
B. Decryption Technique: Step 1: RNS Object Retrieval Taking Alpha Value = 0.5, proper mixing of both the images gives both the direction and the points
67
1100111
5F 61 54 5B
1011111 1100001 1010100 1011011
5E
1011110
Step 6: Character Matrix Deformation
Step 7: Un-Append Figure 6 – RNS Object
58 67
Step 2: Un-Scripting
124
119
120
117
118
123
1111100
124
1110111
119
1111000
120
1110101
117
1110110
118
1111011
123
© 2012, IJARCSSE All Rights Reserved
4C 5B
4F 5E
52 61
45 54
52 R
45 E
Step 8: Hexadecimal Value Retrieval
58 X
Step 3: ASCII Value Retrieval
50 5F
50 P
4C L
4F O
IV. RESULT ANALYSIS VIA SCREENSHOT Plain Text XPLORE Key Text wF+2x1,1+2yL+zA
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Volume 2, Issue 3, March 2012
www.ijarcsse.com V. CONCLUSION The proposed technique culminated through the formation of the stego image, wherein the background image is hidden within the foreground image, gives an impression to the viewers about the availability of the coordinates only, without any direction as well as magnitude. The RNS Object created in the final step of the proposed RNS Model gives a new dimension to the proposed technique of data encryption and data decryption. The proposed technique not only enhances the security quotient on the whole, but also establishes the design and the implementation of an innovative mechanism/methodology to overcome the predicament at bay during diurnal strife in combating malicious intruders and exhibited intrusions.
Figure 7 – RNS Object
REFERENCES Chowdhury, R., Ghosh, S., ―Normalizer Based Encryption Technique [NBET] Using the Proposed Concept of Rubicryption‖, International Journal of Information Technology and Knowledge Management, Volume–4, Number–1, January–June, 2011, Pages 77–80. [2] Chowdhury, R., Ghosh, S., ―Study of Cryptology Based on Proposed Concept of Cyclic Cryptography Using Cyclograph‖, Research Journal of Engineering and Technology, Volume–2, Number–1, January–March, 2011, Pages 17–20. [3] Chowdhury, R., Saha, A., Biswas, P., K., Dutta, A., ―Matrix and Mutation Based Cryptosystem (MMC)‖, International Journal of Computer Science and Network Security, Volume–11, Number–3, March, 2011, Pages 7–14. [4] Singh, A., P., Mishra, A., ―Wavelet Based Watermarking on Digital Image‖, International Journal of Computer Science and Engineering, Volume–1, Number–2, 2010, Pages 86–91. [5] Lou, D., C., Liu, J., L., ―Steganography Method for Secure Communciations‖, Elsevier Science on Computers and Security, Volume–21, Number–5, 2002, Pages 449–460. [6] Bican, J., Janeba, D., Taborska, K., Vesely, J., ―Image Overlay Using Alpha Blending Technique‖, Nuclear Medicine Review, Volume–5, Number–1, 2002, Page 53. [7] Stallings, W., ―Cryptography and Network Security‖, Prentice Hall, 3rd Edition. [8] Kahate, A., ―Cryptography and Network Security‖, Tata McGraw–Hill, 2nd Edition. [9] Balagurusamy, E., ―Programming with Java‖, Tata McGraw–Hill, 3rd Edition. [10] Fadia, A., ―Network Security‖, Macmillan India Limited. [11] www.cryptographyworld.com [1]
Figure 8 – Stego Image of RNS Object
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