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Technical seminar ppt

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  • 1. An Adaptive LSB-OPAP based SecretData HidingbyTEJAS.Sunder the guidance ofProf. PADMAJA VIJAYKUMARECE Dept. AIeMS
  • 2. IntroductionWays of sending informationencryption steganograhy
  • 3. Steganography !encrypt msg cover filewatermarkingAdvantagessecrecyImperceptibilityHigh capacityAccurate extractionfiles such as audio,video,image,etc..
  • 4. Image Steganographyprocess
  • 5. Classical Methods Kirchoff’s golden rule Adaptive Steganography 4LSB substitution technique Model authentication technique
  • 6. Objective of proposed method Enhance embedding capacity of image . An adaptive number of least significant bitssubstitution method with private stego-key. verify whether the attacker has tried tomodify the secret hidden information in thestego-image. embed the hidden information in the coverimage and use digital signature using a keyto verify the integrity from the stego-image.
  • 7. Method key1 consists of some gray-level ranges. Each range substitute different fixed number ofbits into LS part of the 8-bit gray value of thepixels. Pixel gray value “g” that fall within the range Ai-Bi is changed by embedding message bits ofsecret information into new gray value “g’ ”. OPAP is used that make the new gray value “g’” fall within the range Ai-Bi. Digital signature of the secret information withthe key2 were obtained and appended with theinformation
  • 8. Private stego-keygeneration For a gray scale image 8-bit is usedto represent intensity of pixel, so thereare only 256 different gray values anypixel may hold. Different pixels in image may holddifferent gray values let four ranges of gray levels are < A1-B1, A2-B2, A3-B3, A4-B4 > eachrange starting and ending value are in8-bits.
  • 9. Method to decide Bitsinsertion in each range Let the four gray ranges decided bythe stego-key are <A1-B1, A2-B2, A3-B3, A4-B4> number of pixel count from coverimage in each range are < N1, N2,N3, N4 >. Let the ranges be 0-64, 65-127, 128-191, 192-255 Let ranges hold no of pixels 34,13238, 17116, 35148.
  • 10. LSB substitution
  • 11. OPAP – Optimum Pixel AdjustmentProcessK = K+1
  • 12. Example :consider a gray level range 0-32, 3 – bitssubstitution are 111 1 : let 00100000 (32) be pixel value of g, 2 : after LSB method, g’ = 001000111 (39) 3 : g’ < 32, K+1 bit of g’ changed from 0 to1 or via- versa (00101111) and checkedagain to fall within range if not K+2 bit ischanged (00111111) and so on until grayvalue fall within range 00011111(31).
  • 13. IMPLEMENTATION OF ALOS ENCODING ALGORITHM Input: Cover-image, secret message, keys K1, K2. Output: Stego-image. Step1: Read key K1 based on gray-Level ranges. Step2: Read cover image Step3: Decide No. of bits insertion into each range described insection 2.3 Step4: Read the secret message and Convert it into bit stream form. Step5: Read the key K2. Step6: Find the signature using K2 and append with the messagebits. Step7: For each Pixel 7.1: Find gray value g. 7.2: Decide the K-bits insertion based on gray ranges. 7.3: Find K-message bits and insert using method given in section2.4 7.4: Decide and adjust new gray Value g’ using method described inOptimum pixel adjustment process.
  • 14. EXTRACTION ALORITHM Input: Stego-image, keys K1, K2; Output: Secret information; Step1: Read key K1 based on gray-level ranges. Step2: Read the stego image. Step3: Decide No. of bits extraction into each rangedescribed in section 2.3. Step4: For each pixel, extract the K-bits and save intofile. Step5: Read the key K2 and find the signature of bitstream Step6: Match the signature. Step7: End
  • 15. Advantages : High hiding capacity compared to LSB Substitutiontechnique. Robust in nature, i.e., highly secure algorithm since twokeys (key-1 and key-2) are used. We get good quality of the stego image. High water marking level. Provides maximum possible payload. Embedded data is imperceptible to the observer.Limitations : High computational complexity. Requires a lot of overhead to hide a relatively bits ofinformation.This can be overcome by using HIGH SPEED
  • 16. Applications In secret communication system. Military applications. Hiding and protecting of secret data inindustry. Navy and Air force. Business Deals
  • 17. Results and Discussions Lena and baboon 256 × 256 × 3 colour digital imagesRange Cover imageMax bits that canbe embedded(payload)No of bitsembeddedCapacity(bits/pixel)PSNRRange1Lena 65314951360 3.8016 44.94124768 3.141 55.5705115360 3.2268 40.8688Baboon 60952451360 3.2927 44.76684768 3.2 54.8287115360 3.0352 41.7503Range2Lena 69370051360 3.624 43.4944768 3.7338 53.4812115360 3.6078 40.3313Baboon 70008751360 3.6488 43.24794768 3.7192 53.6941115360 3.5019 40.2084
  • 18. The input cover image0200400600The histogram of input cover image0 100 200The output stego image0200400600800The histogram of stego image0 100 200Experimental result using Range1 for Baboon cover image
  • 19. The input cover image0200400600800The histogram of input cover image0 100 200The output stego image05001000The histogram of stego image0 100 200Experimental result using Range2 for Lena cover image
  • 20. Conclusion Enhanced embedding capacity of image . An adaptive number of least significant bits substitutionmethod with private stego-key. whether the attacker has tried to modify the secrethidden information in the stego-image. embeded the hidden information in the cover image anduse digital signature using a key to verify the integrityfrom the stego-image. Experimental results verify that the proposed model iseffective and efficient.
  • 21. References S. Dumitrescu, W. X. Wu and N. Memon, “On steganalysis ofrandom LSB embedding in continuous-tone images”,Proceeding of International conference on image Processing,Rochester, NY, pp. 641-644, 2002. A. Cheddad, J. Condell, K. Curran and P. McKevitt,“Enhancing Steganography in digital images”, IEEE - 2008Canadian conference on computer and Robot vision, pp. 326-332,2008. Ko-Chin Chang, Chien-Ping Chang, Ping S. Huang, and Te-ming Tu, “A novel image steganographic method using Tri-way pixel value Differencing”, Journal of multimedia, vol. 3,issue 2, June 2008. K. S. Babu, K. B. Raja, K. Kiran Kumar, T. H. Manjula Devi, K.R. Venugopal, L. M.Pataki, “Authentication of secretinformation in image steganography”, IEEE Region 10Conference, TENCON-2008, pp. 1-6, Nov. 2008. S. K. Moon and R.S. Kawitkar, “Data Security using DataHiding”, IEEE International conference on computationalintelligence and multimedia applications, vol. 4, pp. 247251,Dec 2007
  • 22. THANK YOU

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