1. 1 影像偽裝術的最新發展 Chair Professor Chin-Chen Chang Feng Chia University National Chung Cheng University National Tsing Hua University

2. 2 Multimedia (Watermarking) Classifications: Visible watermarking Invisible watermarking Robust watermarking Semi-fragile watermarking Fragile watermarking

3. 3 Multimedia (Watermarking) (Cont.) Visible watermarking Easy to embed Clear to see watermark

4. 4 Multimedia (Watermarking) (Cont.) Invisible watermarking Requirements: Good visual quality of watermarked image Robustness Watermarking Watermarked imageOriginal image Watermark

5. 5 Multimedia (Image authentication) Requirements: Detect the tampered area Try to restore the tampered area Solutions: Hamming codes Image Tampered imageDetected imageRestored image

6. 6 Multimedia (Secret sharing) Classification: Meaningless shadows Meaningful shadows Meaningless shadows Requirements: Unexpected user can not see the secret image Good visual quality of reconstructed secret image

7. 7 Multimedia (Secret sharing) (Cont.) Shadow size: 256  256 Image size: 512  512 Sharing Reconstructing PSNR=24 dB (2,4)-threshold secret sharing scheme

8. 8 Multimedia (Secret sharing) (Cont.) Meaningful shadows Requirements: Good visual quality of stego image Secret image extraction and reconstruction Solutions: Applying steganography techniques Applying image authentication mechanisms

9. 9 Multimedia (Secret sharing) (Cont.) Secret image Stego-image Hiding Reconstructed secret image Reconstructing (n,2)-threshold secret sharing scheme Stego-image

10. 10 Multimedia (Visual cryptography) Requirements: Secret message delivery Unexpected user can not see the message from an individual share Solutions: Using shadow patterns Using meaningful shadow images Using Circle Shares

11. 11 Multimedia (Visual cryptography) (Cont.) Shadow 1Shadow 2 Secret Staking

12. 12 Multimedia (Visual cryptography) (Cont.) Shadow 1Shadow 2 Secret Staking

13. 13 Multimedia (Visual cryptography) (Cont.) Share 1 Share 2 Secret 1 “ VISUAL ” Secret 2 “ SECRET ” Staking Rotating 40 o

14. 14 Multimedia (Steganography) Classification: The target of modification Frequency domain (e.g. DCT, DWT, DFT) Spatial domain (e.g. pixel values) Compression domain (e.g. VQ, LAC, SOC) Stego image restoration Irreversible data hiding Reversible data hiding

15. 15 Multimedia (Steganography) (Cont.) Irreversible data hiding Requirements: High capacity Good visual quality of stego images Solutions: Using Sudoku Using wet paper codes concept Using Hamming codes

16. 16 Multimedia (Steganography) (Cont.) Reversible Requirements: Fully reconstructing cover image Good visual quality of stego image High capacity Solutions: Data hiding in VQ indices Data hiding in LAC codes Data hiding in SOC codes …

17. 17 Data Hiding Cover image Hiding system Secret message Stego image 1 0 1 0 1 0 0 1 0 1 1 1 1 0 0

18. 18 Cover Carriers Image Video Sound Text

19. 19 VQ Encoding Codebook Index table 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 (100,125,…,150) Original Image … (20,65,…,110) (90,135,…,120) (120,155,…,80) (50,42,…,98) (49,117,…,25)

20. 20 Previous Work of Steganography on VQ To find the closest pairs

21. 21 Unused CW 0, CW 8, CW 13, CW 14 1 0 CW 1 CW 11,CW 2,CW 3 CW 4, CW 5 CW 6, CW 7 CW 15, CW 10 CW 12, CW 9 d(CW 0, CW 8 ) > TH d(CW 13, CW 14 ) > TH

22. 22 Index Table Unused CW 0, CW 8, CW 13, CW 14 Encode Index Table Original Image

23. 23 A secret message: 1 0 1 0 1 0 0 1 0 1 1 1 1 0 0 Index Table CW 1, CW 2, CW 4, CW 5 CW 6, CW 7 CW 11, CW 3 CW 15, CW 10 CW 12, CW 9 1 0 Secret bits 1 1 0 001 0 1 11 1 0 0 1 0

24. 24 A secret message: 1 0 1 0 1 0 0 1 0 1 1 1 1 0 0 Index Table CW 1, CW 2, CW 4, CW 5 CW 6, CW 7 CW 11, CW 3 CW 15, CW 10 CW 12, CW 9 1 0 Secret bits 1 1 0 001 0 1 11 1 0 0 1 0

25. 25 A secret message: 1 0 1 0 1 0 0 1 0 1 1 1 1 0 0 Index Table Secret bits 1 1 0 001 0 1 11 1 0 0 1 0

26. 26 Zhang and Wang ’ s Method (Embedding) 8794 79545511 20211224 1210 9 01234 0 1 2 3 4 5 6 7 0123456789 11 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 Cover image 1000 2 1 3 5 Secret data: 1000 1011… 77104 Stego image p1p1 p2p2

27. 27 Zhang and Wang ’ s Method (Extracting) 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

28. 28 Sudoku A logic-based number placement puzzle

29. 29 Sudoku (Cont.) 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.

30. 30 Data Hiding Using Sudoku - 1 Reference Matrix M

31. 31 Data Hiding Using Sudoku (Embedding) (Cont.) 871112 79545511 20211224 1210 9 97 Cover Image Stego 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 min.

32. 32 Data Hiding Using Sudoku (Embedding) (Cont.) 871112 79545511 20211224 1210 9 97914 Cover Image Stego 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 min. 279279 Secret data: 011 001 10…

33. 33 Data Hiding Using Sudoku (Extracting) (Cont.) 97914 Stego Image Extracted data: 27 9 = 011 001 2

34. 34 Experimental Results

35. 35 Experimental Results (Cont.) The results of visual quality and Embedding capacity comparisons

36. 36 (7, 4) Hamming Coding Encoding Data: 1 1 0 1 2 p 1 p 2 d 1 p 3 d 2 d 3 d 4 1 0 1 0 1 0 1 d 1  d 2  d 4 = p 1 1  1  1 = 1 d 1  d 3  d 4 = p 2 1  0  1 = 0 d 2  d 3  d 4 = p 3 1  0  1 = 0 d1 d2 d3 d4d1 d2 d3 d4 Encoded data Encoding p 1 p 2 d 1 p 3 d 2 d 3 d 4

37. 37 (7, 4) Hamming Coding (Cont.) Error Detection Received data: 1 0 1 0 1 1 1 Error Position Corrected data: 1 0 1 0 1 0 1 Correcting Parity check matrix H Error bit

38. 38 Matrix Coding Method 000010110000101000001001 000001100000001100000100 000011000000100100001011 11109 634 12911 Cover Image Parity check matrix H (1010100) T = (1 1 1) T Secret data: 1 1 0 0…  0 0 1 00001010 00001001 000001100000001100000100 000011000000100100001011 10 9 634 12911 Stego Image Embedding

39. 39 Matrix Coding Method (Cont.) (0010100) T = (1 1 0) T Extracted secret data: 1 1 0 0… 00001010 00001001 000001100000001100000100 000011000000100100001011 10 9 634 12911 Stego Image Extracting ■ 7 pixels embed 3 bits

40. 40 “ Hamming+1 ” Method 000010110000101000001001 000001100000001100000100 000011000000100100001011 11109 634 12911 Cover Image Parity check matrix H (1010100) T = (1 1 1) T Secret data: 1 1 0 0…  0 0 1 (1+1+0+1+1+0+0+ 1) mod 2= 1 = ? 00001010 00001100 or(0+1+0+1+1+0+0+ 1) mod 2= 0 000011000000101000001001 000001100000001100000100 000011000000100100001011 12109 634 12811 Stego Image Embedding

41. 41 “ Hamming+1 ” Method (Cont.) (0010100) T = (1 1 0) T Extracted secret data: 1 1 0 0… = (0+1+0+1+1+0+0+ 1) mod 2= 0 000011000000101000001001 000001100000001100000100 000011000000100100001011 12109 634 12911 Stego Image Extracting ■ 8 pixels embed 4 bits