steganography using overlapping codebook partition
DESCRIPTION
Steganography using overlapping codebook partition. Source: Signal Processing, Available online 28 November 2007 Authors: Yung-Kuei Chiang, Piyu Tsai Report: Jiun-Lwen Liang Date: 2012/06/07. Outline. Introduction The proposed scheme - PowerPoint PPT PresentationTRANSCRIPT
Source: Signal Processing, Available online 28 November 2007
Authors: Yung-Kuei Chiang, Piyu Tsai
Report: Jiun-Lwen LiangDate: 2012/06/07
Steganography using overlapping codebook partition
Outline
2012/6/72
Introduction
The proposed scheme
1. codebook partitioning
2. embedding procedure
3. extracting procedure
Experimental results
Conclusions
Introductions
2012/6/73
Communications security over the Internet is becoming more and more critical because of the digitization of data and networking of communications.
The steganography using overlapping codebook partition is proposed to extend the hiding capacity of a cover image and preserve the quality of a stegoimage.
Introductions
2012/6/74
Jo and Kim proposed an index-based watermarking scheme.
Chang and Wu presented an adaptive VQ-based data hiding scheme which is based on a codeword grouping technique.
Related work - VQ
2012/6/75
Vector quantization (VQ) – Codebook generation
Codebook
Training Images
0
1
2
.
.
.
N-1
Codeword1
Codeword2
Codeword3
.
.
.
Codeword N
2012/6/76
Vector quantization (VQ) – Encoding
2 62 60 174 …
100 95 202 174 …
…
…
…
…
Codebook
Index table
Original Image
0(16, 200, …,
90)
1 (35, 22, …, 100)
2 (40, 255, …, 59)
.
.
.
.
.
.
254 (90, 102, …, 98)
255 (145, 16, …, 99)
Related work - VQ
2012/6/77
Vector quantization (VQ) – Decoding
2 62 60 174 …
100 95 202 174 …
…
…
…
…
0(16, 200, …,
90)
1 (35, 22, …, 100)
2 (40, 255, …, 59)
.
.
.
.
.
.
254 (90, 102, …, 98)
255 (145, 16, …, 99)
Codebook
Index table
VQ Coded Image
Related work - VQ
The proposed scheme
2012/6/78
Codebookpartition
The proposed scheme -codebook partitioning
2012/6/79
sort the SEDs of each codeword between all other codewordsfrom small to big
clustered into four-member sub-cluster ( summed SED < TH1)
clustered into single-member sub-cluster
clustered into three-member sub-cluster ( summed SED < TH2)
clustered into two-member sub-cluster ( summed SED < TH3)
The proposed scheme -codebook partitioning
2012/6/710
2
1
( , ) ( ) h h
i j ik jkk
SED C C c c
Codebook partition algorithm
Squared Euclidean Distance(SED)
Thresholds TH1, TH2, TH3
The proposed scheme -codebook partitioning
60 61 62 63 64 65 66 67
60 0 80 200 300 250 90 100 400
61 80 0 110 120 185 285 210 310
62 200 110 0 350 190 160 220 320
63 300 120 350 0 220 260 230 330
64 250 185 190 220 0 180 480 320
65 90 285 160 260 180 0 140 500
66 100 210 220 230 480 140 0 270
67 400 310 320 330 320 500 270 0
2012/6/7 11
TH1=4550+80+90+100=270
0+80+110+120=310
0+110+160+190=460
0+120+220+230=570
0+180+185+190=555
0+90+140+160=390
0+100+140+210=450
0+270+310+320=900
60 → 60,61,65,66
61 → 60,61,62,63
65 → 60,62,65,66
66 → 60,61,65,66
TH2=350
0+110+160=270
0+120+220=340
0+180+190=370
0+270+310=580
62 → 62,61,65
63 → 63,61,64
TH3=200
0+190=190
0+270=270
64→64,62
67 →67
Residual
The proposed scheme -embedding procedure
(four-member sub-cluster)
Member
order 0 1 2 3
Binary expression 00 01 10 11Codeword
index 208 199 202 209
2012/6/7 12
209 64 78
…. …. ….
…. …. ….
Index table
199
209
index
secrete message: 0 1 1 0 1 1 0 0 1 1 …
The proposed scheme -embedding procedure
(three-member sub-cluster)
199 64 78
…. …. ….
…. …. ….
Member order 0 1 2
Codeword index 64 71 66
Codeword index 75 78 67
index
64
78
Member order in
sub-cluster
Member order in
sub-cluster
Three-bit
Values
0 0 000
0 1 001
0 2 010
1 0 011
1 1 100
1 2 101
2 0 110
2 1 111
2 2 N/A2012/6/7 13
embed bits : 101
Secret bits valued at 5
Index table
71 67
The proposed scheme -embedding procedure
2012/6/7 14
member order 0 1 2 3
sub-cluster A 180 176 172 175
sub-cluster B 180 179 172 175
sub-cluster C 178 177 183 175
secrete bit: 01
175 64 78
…. …. ….
…. …. ….
179 64 78
…. …. ….
…. …. ….
Find the most similar one to the originalindex 175
The proposed scheme -Extracting procedure
199 71 67
…. …. ….
…. …. ….
Codeword index
208 199 202 209
Member order
0 1 2 3
Binary expression
00 01 10 11
2012/6/7 15
Index table Codeword index
… 199 … …
…
199
209
…
index
…
secrete bit : 01 codebook
The proposed scheme -Extracting procedure
2012/6/716
199 71 67
…. …. ….
…. …. ….
Member order in
sub-cluster
Member order in
sub-cluster
Three-bit
Values
0 0 000
0 1 001
0 2 010
1 0 011
1 1 100
1 2 101
2 0 110
2 1 111
2 2 N/A
Secret bits 101
Member order 0 1 2
Codeword index … 71 …
Codeword index … … 67
index
71
67
codebook
Index table
Experimental results
2012/6/717
(f) Gold
(1) IEEE (2) CCU (3) NUU
512X512 pixels 128X128 pixels
Experimental results(2/5)
2012/6/718
Original image
Embedded image
“IEEE” “CCU” “NUU”
Experimental results
2012/6/719
Experimental results
2012/6/720
Cover image(512×512)
Secret data(256×256=65536 bits)
Experimental results
2012/6/721
Secret data 256x256
Experimental results
2012/6/722
Conclusion
2012/6/723
This method increases the hiding capacity and still have the great image quality.