1. Information Hiding and Its Applications
Chin-Chen Chang (張 真 誠)
逢甲大學 講座教授
中正大學 榮譽教授、合聘教授
清華大學 合聘教授

2. Information Hiding Hiding system Stego image Cover image
Secret message

3. Cover Carriers
Image
Video
Sound
Text
Compression Code

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

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

6. d(CW0, CW8) > TH d(CW13, CW14) > TH Unused CW0, CW8, CW13, CW14

7. Encode Index Table CW0, CW8, CW13, CW14 Unused Index Table
Original Image
Index Table
Unused
CW0,
CW8,
CW13,
CW14

8. A secret message: 1 1 1 1 1 1 1 1
Index Table
Secret bits
CW1, CW2,
CW4, CW5
CW6, CW7
CW11, CW3
CW15, CW10
CW12, CW9 1

9. A secret message: 1 1 1 1 1 1 1 1
Index Table
Secret bits
CW1, CW2,
CW4, CW5
CW6, CW7
CW11, CW3
CW15, CW10
CW12, CW9 1

10. A secret message: 1 1 1 1 1 1 1 1
Index Table
Secret bits

11. Shortcoming Irreversible
Original index values can not be recovered after extraction

12. Find the dissimilar pairs
(De-clustering) …
CW1
CW8
CW2
CW9
CW3
CW10
CW4
CW11
CW5
CW12
CW6
CW13
CW7
CW14 1
Dissimilar

13. Encode
Index Table
Original Image

14. Embedding Using Side-Match
CW1
CW8
:Dissimilar Pair
Assume X = CW1
V0 = ((U13+L4)/2, U14, U15, U16, L8, L12, L16)
V1 = (X1, X2, X3, X4, X5, X9, X13)CW1
V8 = (X1, X2, X3, X4, X5, X9, X13)CW8
d1=Euclidean_Distance(V0, V1)
d8=Euclidean_Distance(V0, V8)
If (d1<d8), then Block X is replaceable
Otherwise, Block X is non-replaceable

15. CW1
CW8
:Dissimilar Pair
V0 = (( )/2, 137, 132, 131, 131, 134, 140)
= (130, 137, 132, 131, 131, 134, 140)

16. V0 = (130, 137, 132, 131, 131, 134, 140)
(128,136,130,130,129,?,?,?,125,?,?,?,142,?,?,?)
V1 = (128, 136, 130, 130, 129, 125, 142)
d1=Euclidean_Distance(V0, V1)
=(( )2+( )2+( )2+( )2+
( )2+( )2+( )2)1/2
=4.36
Codebook

17. Here, d1 < d8 => So block X is replaceable
V0 = (130, 137, 132, 131, 131, 134, 140)
d1=4.36
(2, 19, 43, 56, 9, ?, ?, ?, 30, ?, ?, ?, 12, ?, ?, ?)
V8 = (2, 19, 43, 56, 9, 30, 12)
d8=Euclidean_Distance(V0, V8)
=((130-2)2+(137-19)2+(132-43)2+(131-56)2+
(131-9)2+(134-30)2+(140-12)2)1/2
=293.15
Here, d1 < d8 => So block X is replaceable
Codebook

18. A secret message: 1 1 1 1 1 1 1 1
Secret bits
Index Table
If (d6<d13)
CW1, CW2,
CW3, CW4
CW5, CW6
CW7 , CW15
CW8, CW9
CW10, CW11
CW12, CW13
CW14 , CW0 6
Embedding Result 1

19. A secret message: 1 1 1 1 1 1 1 1
Secret bits
Index Table
If (d2<d9)
CW1, CW2,
CW3, CW4
CW5, CW6
CW7, CW15
CW8, CW9
CW10, CW11
CW12, CW13
CW14 , CW0 6 9
Embedding Result 1

20. A secret message: 1 1 1 1 1 1 1 1
Secret bits
Index Table
If (d12>=d5)
CW1, CW2,
CW3, CW4
CW5, CW6
CW7 , CW15
CW8, CW9
CW10, CW11
CW12, CW13
CW14 , CW0 6 9
15||12
Embedding Result 1
CW15: embed 1

21. A secret message: 1 1 1 1 1 1 1 1
Secret bits
Index Table
If (d9>=d2)
CW1, CW2,
CW3, CW4
CW5, CW6
CW7 , CW15
CW8, CW9
CW10, CW11
CW12, CW13
CW14 , CW0 6 9
15||12
0||9
Embedding Result 1
CW0: embed 0

22. Steganographic Index Table
Extraction and Recovery 6 9
15||12
0||9 1
Extract Secret bits
Steganographic Index Table
If (d6<d13)
CW1, CW2,
CW3, CW4
CW5, CW6
CW7 , CW15
CW8, CW9
CW10, CW11
CW12, CW13
CW14 , CW0 6
Recovery 1

23. Steganographic Index Table
Extraction and Recovery 6 9
15||12
0||9 1
Extract Secret bits
Steganographic Index Table
If (d9>=d2)
CW1, CW2,
CW3, CW4
CW5, CW6
CW7 , CW15
CW8, CW9
CW10, CW11
CW12, CW13
CW14 , CW0 6 2
Recovery 1

24. Steganographic Index Table
Extraction and Recovery 6 9
15||12
0||9 1 1
Extract Secret bits
Steganographic Index Table
CW1, CW2,
CW3, CW4
CW5, CW6
CW7 , CW15
CW8, CW9
CW10, CW11
CW12, CW13
CW14 , CW0 6 2 12
Recovery 1

25. Steganographic Index Table
Extraction and Recovery 6 9
15||12
0||9 1 1
Extract Secret bits
Steganographic Index Table
CW1, CW2,
CW3, CW4
CW5, CW6
CW7 , CW15
CW8, CW9
CW10, CW11
CW12, CW13
CW14 , CW0 6 2 12 9
Recovery 1

26. Experiments Codebook size: 512 Codeword size: 16
The number of original image blocks:128*128=16384
The number of non-replaceable blocks: 139

27. Experiments Codebook size: 512 Codeword size: 16
The number of original image blocks:128*128=16384
The number of non-replaceable blocks: 458

28. Side Match Vector Quantization (SMVQ): Encoding and Decoding

29. Side Match Vector Quantization (SMVQ)
Image compression technique w h
131
137
129
134
140
132
130
137
132
131
134
140
Image
Seed Blocks (VQ)
Residual Blocks (SMVQ)
Side Match Vector Quantization Encoder

30. Side Match Vector Quantization Encoder
(130,137,132,131,131,?, ?, ?, 134, ?, ?, ?,140, ?, ?, ?)
from Codebook
Residual Block (forecasted pixels)
Index value 12 to encode block X

31. Side Match Vector Quantization Decoder
Using VQ Decoder
Using SMVQ Decoder
Decoded Block
Residual Block (forecasted pixels)
Index Table

32. Hiding Secret Data Using SMVQ

33. Original image (512*512 pixels)
Hiding Secret data
Seed Blocks (VQ)
Residual Blocks (SMVQ)
Original image (512*512 pixels)

34. Residual Block (forecasted pixels)
SMVQ
Residual Block (forecasted pixels)
d(CW12,X)<THSMVQ code: ‘1 1100’
d(CW12,X)>THSMVQ VQ encoder code: ‘ ’

35. Residual Block (forecasted pixels)
Hiding Secret in Residual Blocks (SMVQ)
Secret message …
d(CW12,X)<THSMVQ code: ‘1 1100’
d(CW12,X)>THSMVQ VQ encoder code: ‘ ’
Residual Block (forecasted pixels)

36. Residual Block (forecasted pixels)
Hiding Secret in Residual Blocks (SMVQ)
Secret message …
d(CW1,X)<THSMVQ code: ‘1 0001’
d(CW1,X)>THSMVQ VQ encoder code: ‘ ’
Residual Block (forecasted pixels)

37. Residual Block (original pixels)
Hiding Secret in Residual Blocks (VQ)
Secret message …
d(CW253,X)<THVQ code: ‘ ’
d(CW253,X)>THVQ Hide no secret code: ‘ ’
Residual Block (original pixels)

38. Image Seed Blocks Using VQ: hide no secret (“0” + 8-bits) 重點: 全部沒有藏
Residual
Blocks
Using SMVQ: hide secret (“1” + 4-bits)
Using VQ 1.hide secret (“0” + 8-bits) 2.hide no secret (“1” + “0000” + 8-bits)
重點: 1. 使用SMVQ的Block一定有藏 2. 使用VQ的Block有的有藏， 有的沒藏
Image

39. Extracting Secret in Residual Blocks
Code …
Hide using SMVQ
Hide Secret: ‘1’
Hide no secret
Hide Secret: ‘0’
Hide using VQ

40. Experiments
Image size: 512х512

41. Experiments
State codebook size = 16
Codebook size= 256

42. Pixel Domain and Index Domain Information Hiding Schemes
Tzu-Chuen Lu (呂慈純博士)
Department of Information Management
Chaoyang University of Technology
(朝陽科技大學 資訊管理系)

43. Information Hiding
illegal
Information
Internet
Sender
Receiver

44. Information Hiding Information illegal Internet Sender Information
Receiver

45. Information Hiding - LSB5 11 10 13 20 31 41 51 27 17 44 37 85 14 35 34 15 85 37 45 17 10 27 51 40 31 20 12 11 5
Image
Information
Stego Image
Least Significant Bit (LSB) 1

46. Information Hiding - LSB34 15 85 37 45 17 10 27 51 40 31 20 12 11 5 5 11 10 13 20 31 41 51 27 10 17 44 37 85 14 35
Image
Stego-Image
MSE =
=0.4375
PSNR (Peak Signal to Noise Ratio) =
=51.72
Payload = 1 (bit per pixel, bpp)

47. Information Hiding - LSB
PSNR = 43.27
Payload = 2 bpp
Trade-off: Image quality and Payload
Robustness

48. Pixel Domain Quantization-based Information Hiding Scheme

49. Quantization-based Information Hiding Scheme34 15 85 37 45 17 10 27 51 40 31 20 12 11 5
Image 6 12
Information 35 15 85 38 45 17 10 27 51 40 32 20 12 6
Modified Image

50. 255 8 16 24 32
248
240 1 2 3 31 4 1 6 11 10 12 12 8 16 24 1 20 32 40 51 6 27 10 17 45 38 85 15 35
Modified Image

51. 255 8 16 24 32
248
240 1 2 3 31 4 11 10 13 12 12 8 16 24 1 20 32 40 51 10 27 10 17 45 38 85 15 35
Modified Image

52. Quantization-based Information Hiding Scheme - Extraction Process
255 8 16 24 32
248
240 1 2 3 31 4 37 19 86 43 50 20 13 33 53 44 40 26 14 11
Stego Image
PSNR = 34.91
Payload = 1 bpp

53. 255 1 2 3 4 7 31 32 1 1 8 16 24 48 56
248 37 19 86 43 50 20 13 33 53 44 40 26 14 11
Stego Image 6 10 51

54. Quantization-based Information Hiding Scheme -Repairing Process37 19 86 43 50 20 13 33 53 44 40 26 14 11
Stego Image 35 15 85 38 45 17 10 27 51 40 32 20 12 6
Repaired Image
PSNR = 53.18
Payload = 1 bpp
PSNR = 34.91
Payload = 1 bpp

55. Quantization-based Information Hiding Scheme -Robustness
255 8 16 24 32
248
240 1 2 3 31 4 37 22 86 43 50 18 13 33 53 44 40 29 10 14 9
Stego Image 37 19 86 43 50 20 13 33 53 44 40 26 14 11
Stego Image

56. Experimental Results
Modified Images
Stego Images

57. Experimental Results Payload: 1 bpp PSNR Lena Peppers Airplane Baboon8
Modified Image
51.14
51.13
51.15
Stego Image
34.79
34.80
34.86
34.81
Repaired Image 4
51.12
40.71
40.72
40.74
40.73
Payload: 1 bpp

58. Information
Compressed codes:
…..
Internet
Sender ?
Receiver

59. Compressed codes: 1011101111….. Information Information Internet
Sender
Receiver
Information

60. Index Domain Reversible Hiding Scheme Based on Switching Tree Coding

61. Vector Quantization (VQ)7 7 9 10
Index table
Original Image
VQ Encoder

62. Vector Quantization (VQ)
Index table
Reconstructed Image
VQ Decoder

63. Switching-Tree Coding (STC)
Sheu proposed the STC algorithm in 1999
Re-encode the index table
Index Table U
the current index L

64. Switching-Tree Coding (STC)
If A = 7, then A = U  A’= 11
If A = 10, then A = L  A’= 10

65. Switching-Tree Coding (STC)
If A = 14  A’=01 +‘00011’
If A = 17  A’=00 +‘ ’

66. Information Hiding on STC Codes (IHSTC)
Index table
A’ = 00+(10)
00+(25)
00+(21) …
00+(17)

67. Information Hiding on STC Codes (IHSTC)
‘10’
A’ = 00+(10)
00+(25)
00+(21) …
00+(17)

68. Information Hiding on STC Codes (IHSTC)1
‘10’
A’ = 00+(10)
00+(25)
00+(21) …
00+(17)
10+00+(128) …

69. Extraction and Reconstruction
00+(25)
00+(21) …
00+(17)
(128) … 10 10 25 21
100 10 17 17
Information:

70. Extraction and Reconstruction
00+(25)
00+(21) …
00+(17)
(128) … 10 10 25 21
100 17
128 66
237
100
Information: 0 1

71. Experimental Results Image PSNR NSTC Compression Ratio Payload (bpp)
Lena
29.87
11,129
0.39
0.04
Pepper
29.49
10,568
0.40
Baboon
23.079
4,771
0.55
0.02
Airplane
28.58
11,470
0.35

72. Conclusions Information Hiding Pixel-domain
Quantization-based Hiding Scheme
Index-domain
Reversible Hiding Scheme Based on STC

73. Future Works Information Hiding Applications
Watermarking, copyright protection, …
Reversible Information Hiding
Audio, Video, HTML, Text, DNA Sequence
Other Compression Methods
JPEG, Wavelet, MPEG

74. Thanks for your attention!!