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Aug 08, 2015



  1. 1. JPEG Image Steganalysis Using Variation Technique IIT School of Applied Technology Stephen Daniel Indhi Powlette Ana Orozco Cruz Tovar
  2. 2. Steganography Steganography is the art of passing information in a manner that the existence of the message is unknown.
  3. 3. Steganalysis Steganalysis is the study of detecting a hidden message in an object.
  4. 4. Project Goals Create JPEG images with hidden data using steganographic tools Use Variation Technique to analyze clean and dirty images Test variation technique validity by analyzing clean and dirty images
  5. 5. What is JPEG? JPEG stores 24 bits of color per pixel = 16 million colors JPEG is able to display rich colors Can alter up to 3,932 pixels in a 65,535X65,535 pixel image JPEG is a lossy compression algorithm JPEG discards some data when compressed to reduce file size
  6. 6. JPEG Compression Compresses 8x8 pixel blocks from RGB to YCbCr
  7. 7. Least Significant Bit Is a common technique used in Steganography LSB is the lowest value in the bit order LSB is replaced with the hidden data Allows stego image to not appear significantly different from original
  8. 8. 1 2
  9. 9. Stego & Steganalysis Steganography Steganography Steganalysis Stego
  10. 10. Variation Technique Developed by Jessica Fridrich and first detailed her book. Statistical analysis may uncover clues of hidden data in an image.
  11. 11. Entropy Occurs when hidden data is embedded into an image Random uniform noise from the hidden data Entropy increases when hidden data is embedded
  12. 12. Variation Technique It is a measure of the entropy in an image The more hidden information in the carrier, the amount of entropy increases
  13. 13. Process 150 Clean Images 150 Outguess Images 150 F5 Images Text files ranged from 65 bytes to over 9000 bytes
  14. 14. Variation Formula
  15. 15. Steganographic Tools Outguess Open source program Hides data in least significant bit F5 Hides data by implementing matrix encoding Improves the efficiency of embedding
  16. 16. Steganalysis Tools JPEGSnoop
  17. 17. Steganalysis Tools (Cont.) MATLAB
  18. 18. Histograms
  19. 19. Results
  20. 20. Conclusion Aside from Jessica, no one really has tried using the variation technique Analysis with variation technique shows interesting results for F5 and Outguess Differences in result values could be attributed to different hiding methods used by F5 and Outguess
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