a secret information hiding scheme based on switching tree coding
DESCRIPTION
A Secret Information Hiding Scheme Based on Switching Tree Coding. Speaker: Chin-Chen Chang. Outline. VQ image compression Watermarking Search order coding (SOC) Switching tree coding (STC). VQ Image Compression. VQ Compression. w. h. Image. Index table. Vector Quantization Encoder. - PowerPoint PPT PresentationTRANSCRIPT
A Secret Information Hiding Scheme Based on
Switching Tree Coding
Speaker: Chin-Chen Chang
Outline
VQ image compression
Watermarking
Search order coding (SOC)
Switching tree coding (STC)
VQ Image Compression
ImageIndex table
Vector Quantization Encoder
wh
VQ Compression
ImageIndex table
Vector Quantization Decoder
wh
VQ Compression
PSNR = 29.62 dB Accuracy rate 99.95%
Watermarking
CW0
CW1
CW2
CW3
CW4
CW9
CW10
CW11
CW12
CW6
CW7
CW8
CW14
CW15
CW13
CW5
CODEBOOK
Finds the nearest pairs
CW0
CW1
CW2
CW3
CW4
CW9
CW10
CW11
CW12
CW6
CW7
CW8
CW14
CW15
CW13
CW5
Find d(CW0, CW8) > TH
d(CW13, CW14) > TH
Unused
CW0, CW8, CW1
3, CW1
4
hide 1
hide 0
CW1
CW11
,CW2
,CW3
CW4, CW5
CW6, CW7
CW15, CW10
CW12, CW9
w
h
Original Image Index Table
Index TableUnused
CW0, CW8,
CW13, CW14
Encode
Water mark: 1 0 1 0 1 0 0 1 0 1 1 1 1 0 0
Index Table
11
00 0 1
0 11 1
10
0
CW1, CW2,
CW4, CW5
CW6, CW7
CW11, CW3
CW15, CW10
CW12, CW9
hide 1 hide 0
1 0
Water mark
Water mark: 1 0 1 0 1 0 0 1 0 1 1 1 1 0 0
Index Table
11
00 0 1
0 11 1
10
0
CW1, CW2,
CW4, CW5
CW6, CW7
CW11, CW3
CW15, CW10
CW12, CW9
hide 1 hide 0
1 0
Water mark
Water mark: 1 0 1 0 1 0 0 1 0 1 1 1 1 0 0
Index Table
11
00 0 1
0 11 1
10
0
1 0
Water mark
Search-Order Coding (SOC)
An example for indices of VQ
Search-Order Coding (SOC)
321
04
5
6 7 8 9 10
11
Searched point Non-searched point
31 207 207
211
31 207 8 20731 211 8 735 31 8 7
The compressing steps
Search-Order Coding (SOC)
P1 = 1 00011111
Indicator
P2 = 1 11001111
P3 = 0 00
…
P6 = 0 10
Compression codes = 100011111 111001111 000 …
Information hiding on the SOC codes
The proposed scheme: - Information hiding: to embed secret data into host image - Steganography :
to embed secret data into host image and the interceptors will not notice the existence of secret data
- Based on SOC
Information hiding on the SOC codes
Main idea:Ex. receiver receives the compression codes : 010101101110110110011000011
SOC SOC SOCOIVOIV(original index value)
It means that the embedded secret data is “01100” if SOC is represented to hide “0” and OIV is represented to hide “1”.
Information hiding on the SOC codes
Method:ex. A 3*3 index table:
1 2 3
1 18 21 31
2 30 30 31
3 29 30 32
If the secret data is “111110100”, then the hiding position of each bit will be in the raster scan order.
Embedding phase:
Defined: “0” embedded into SOC and
“1” embedded into OIV.
SOC ====> there is nothing that needs to change for its
compression codes
hide “0”
SOC ====> translate SOC into OIV
(give up SOC coding and keep the OIV)
hide “1”
OIV ====> there is nothing that needs to change hide “1”
OIV ====> translate OIV into SOC
ex.
hide “0”
+ OIV11(SOC)
Information hiding on the SOC codes
Information hiding on the SOC codes
Ex.
compression codes are still OIV: 100010010
translate SOC into OIV : 000 => 100011110
translate OIV into SOC : 100100000 => 01100100000
Cost table (bits):
Information hiding on the SOC codes
Security: For enhancing the security of our
method, the position in the index table for hiding each bit of secret data can be determined by using pseudo random number generator, and the secret data can be encrypted by using traditional cryptography system such as DES or RSA in advance.
Information hiding on the SOC codes
Experimental results
Experimental results
Experimental results
Experimental results
Switching tree coding (STC)
Switching-tree coding (STC)
Sheu proposed the STC algorithm in 1999
Re-encode the index table
the current index
U
L
Switching-tree coding (STC)
If P = 7, then P = U P’ = ‘11’
If P = 10, then P = L P’ = ‘10’
If P = 14, then P = A in index (3) P’ = ‘01’ || index (3) = ‘0100011’
If P = 17, then P’ = ‘01’ || (17) = ‘0010001’
Information Hiding on the STC codes (IHSTC)
Information Hiding on the STC codes (IHSTC)
Watermark: 0 1 0 0 1 1 0 0 0 1 1 0 1 0 …
Index table
Information Hiding on the STC codes (IHSTC)
Watermark: 0 1 0 0 1 1 0 0 0 1 1 0 1 0 …
P’ = ‘00’||(10)
‘00’||(25)
‘00’||(21) … ‘00’||(17)
Information Hiding on the STC codes (IHSTC)
Watermark: 0 1 0 0 1 1 0 0 0 1 1 0 1 0 …
P’ = ‘00’||(10)
‘00’||(25)
‘00’||(21) … ‘00’||(17)
‘10’
Information Hiding on the STC codes (IHSTC)
Watermark: 0 1 0 0 1 1 0 0 0 1 1 0 1 0 …
P’ = ‘00’||(10)
‘00’||(25)
‘00’||(21) … ‘00’||(17)
‘10’
‘10’ ‘00’||(128) …
Information Hiding on the STC codes (IHSTC)
Watermark: 0 1 0 0 1 1 0 0 0 1 1 0 1 0 …
P’ = ‘00’||(10)
‘00’||(25)
‘00’||(21) … ‘00’||(17)
‘10’
‘10’ ‘00’||(128) …
‘11’
Three binary connection tree
Three binary connection tree
If U-length > L-length then Tree B
If U-length < L-length then Tree C
Otherwise Tree A
Tree B
Tree C
Experiment results
Image size = 512*512, n = 3 and |H| = 1024
Image size = 512*512, n = 3 and |H| = 2048
Image size = 512*512, n = 3 and |H| = NSTC
Experiment results
Image size = 512*512, n = 5 and |H| = 1024
Image size = 512*512, n = 5 and |H| = 2048
Image size = 512*512, n = 5 and |H| = NSTC