1. 1 濕影像的資訊隱藏技術 Chair Professor Chin-Chen Chang Feng Chia University National Chung Cheng University National Tsing Hua University http://msn.iecs.fcu.edu.tw/~ccc 1

2. 2 Secrets Sender Receiver Internet Data Embedding ‧ Steganography - prison problem ‧ Reversible data hiding - Medical image - Military image -Quality and capacity Secrets

3. 3 01234 12340 23401 01234 01234 … …… 255 p2p2 p1p1 01234 0 1 2 3 4 0 2 4 1 3 012340 Magic Matrix Zhang, X. P. and Wang, S. Z., “Efficient Steganographic Embedding by Exploiting Modification Direction,” IEEE communications letters, vol. 10, no. 11, pp. 1-3, Nov., 2006. n=2, F(2, 3)=3 s=1 (p 1 ', p 2 ') = (2, 2) F(p 1, p 2 ) = (1*p 1 + 2*p 2 ) mod (2n+1)

4. 4 Data Hiding Using Sudoku (1/8)  Spatial domain data embedding  Sudoku  A logic-based number placement puzzle

5. 5 Data Hiding Using Sudoku (2/8)  Property Possible solutions: 6,670,903,752,021,072,936,960 (i.e. ≈ 6.671×10 21 ) A Sudoku grid contains nine 3 × 3 matrices, each contains different digits from 1 to 9. Each row and each column of a Sudoku grid also contain different digits from 1 to 9.

6. 6 1 2 Data hiding using Sudoku (3/8) Review Zhang and Wang’s method (Embedding) 8794 79545511 20211224 1210 9 Extracting function: 01234 0 1 2 3 4 5 6 7 01234567891011 8 9 10 11 255 0123401 … 2340123401 40123401234 : 0 23 123401234012 34012340234 012340123401 2340123401 40123401340 23 123401234012 340123401234 012340123401 234012340123 012340123401 0 2 4 1 3 0 2 4 1 3 0 2 … … … … … … … … … … … … :::::::::::: Magic Matrix Cover image 1000 2 1 3 5 Secret data: 1000 1011… 77104 Stego image p1p1 p2p2

7. 7 01234 0 1 2 3 4 5 6 7 01234567891011 8 9 10 11 255 0123401 … 2340123401 40123401234 : 0 23 123401234012 340123401234 012340123401 2340123401 401234012340 23 123401234012 340123401234 012340123401 234012340123 012340123401 0 2 4 1 3 0 2 4 1 3 0 2 … … … … … … … … … … … … :::::::::::: Magic Matrix 77104 Stego image 1 351 35 Extracted secret data: 1000 2 p1p1 p2p2 Data hiding using Sudoku (4/8) Review Zhang and Wang’s method (Extracting)

8. 8 Data hiding using Sudoku (5/8) - 1 Reference Matrix M

9. 9 Data hiding using Sudoku (Embedding) (6/8) 871112 79545511 20211224 1210 9 Cover Image Secret data: 011 001 10… 279279 d(, ) = ((8-8) 2 +(4-7) 2 ) 1/2 =3 d(, ) = ((9-8) 2 +(7-7) 2 ) 1/2 =1 d(, ) = ((6-8) 2 +(8-7) 2 ) 1/2 =2.24 79 Stego Image min.

10. 10 Data hiding using Sudoku (Embedding) (7/8) 871112 79545511 20211224 1210 9 Cover Image d(, ) = ((11-11) 2 +(15-12) 2 ) 1/2 =3 d(, ) = ((15-11) 2 +(12-12) 2 ) 1/2 =4 d(, ) = ((9-11) 2 +(14-12) 2 ) 1/2 =2.83 91479 Stego Image min. 279279 Secret data: 011 001 10…

11. 11 Data hiding using Sudoku (Extracting) (8/8) 97914 Stego Image Extracted data: 27 9 = 011 001 2

12. 12 Magic Matrix Duc, K., Chang, C. C., “A steganographic scheme by fully exploiting modification directions,” Technique Report of Feng-Chia University. r = F(p i, p j ) = ((t-1) × p i + t × p j ) mod t 2 t bits per pixel pair

13. 13 Color retinal imageSegmented image

14. 14 Wet Paper Coding Key Fridrich, J. Goljan, M., Lisonek, P. and Soukal, D., “Writing on Wet Paper,” IEEE Transactions on Signal Processing, vol. 53, no. 10, pp. 3923- 3935, 2005

15. 15 Wet Paper Coding (2/2) Random Matrix LSB of Cover Image Secret Data 2130 Cover Image ×= ? The important area is marked as wet pixel 203031 Stego-image

16. 16 Wet Paper Coding with XOR Operation Key Eight groups {31}, {35, 31, 32}, {34, 35, 33}, {32}, {33}, {35, 35}, {33, 33, 34}, {32, 32} At least one dry pixel Secrets: 0 1 0 1 0 1 1 1 LSB(35) ⊕ LSB( 31) ⊕ LSB(32) 1 {35, 31, 33} LSB(31) 0 {30} Stego-pixels 30 35 31 33 343533 32353433 353233

17. 17 30 35 31 33 343533 32353433 353233 Secret Extracting LSB(30) = 0 LSB(35) ⊕ LSB(31) ⊕ LSB(33) =1 LSB(34) ⊕ LSB(35) ⊕ LSB(33) = 0 LSB(33) = 1 LSB(32) = 0 LSB(35) ⊕ LSB(34) = 1 LSB(33) ⊕ LSB(33) ⊕ LSB(35)= 1 LSB(32) ⊕ LSB(33) = 1

18. 18 Proposed Scheme (1/6) Key S = 3, 1, 2, 3, 1, 0, 0 Three types: - Restricted Pairs of Wet Pixels (RPW) - Non-restricted Pairs of Wet Pixels (NRPW) - Pairs of Dry Pixels (DP) Embeddable

19. 19 35 (p 1, p 2 ) = (31, 35), n=2 Proposed Scheme (2/6) S=3 (p 1 ', p 2 ') = (33, 35) x y

20. 20 Proposed Scheme (3/6) S=1 (p 1 ', p 2 ') = (31, 31) y x 32 (p 1, p 2 ) = (31, 32), n=2

21. 21 32 (p 1, p 2 ) = (33, 32), n=2 Proposed Scheme (4/6) S=2 (p 1 ', p 2 ') = (34, 32)

22. 22 333432 33 35 34353432 31 3335 Proposed Scheme (5/6) 333432 33 35 34353432 31 3335 Key 333432 33 35 34353432 31 3335

23. 23 333432 33 35 34353432 31 3335 S = 3, 1, 2, 3, 1, 0, 0 1 2 4 5 3 6 7 r = F(p i, p j ) = ((t-1) × p i + t × p j ) mod t 2 t=2

24. 24 Experimental Results (1/3) t= 2 (192 Kb) PSNR = 56.18 t = 3 (304 Kb) PSNR = 46.93 t = 4 (384 Kb) PSNR = 44.96 t= 6 (496 Kb) PSNR = 38.72 t = 8 (576 Kb) PSNR = 34.58 Cover Image

25. 25 Experimental Results (2/3)

26. 26 Experimental Results (3/3) [3] Fridrich, J., Goljan, M., Lisonek, P. and Soukal, D., “Writing on wet paper,” IEEE Transactions on Signal Processing, vol. 53, no. 10, pp. 3923-3935, 2005.

27. 27 Conclusions  A novel steganographic technique with the fully exploiting modification (FEM) is proposed for digital images.  The experiments confirm that our proposed scheme can achieve the goals of high capacity and good visual quality.