1. Reversible Data Hiding in Encrypted Images With Distributed Source Encoding
Source: IEEE Transactions on Circuits and Systems for Video Technology Vol.26 No.4 April 2016
Authors: Zhenxing Qian; Xinpeng Zhang
Speaker: ZhaoHua Zhu
Date: 17/11/2016

2. Outline
Framework
Proposed Scheme
Experiment Result
Conclusions

3. Framework

4. Proposed Scheme(1/11) ——Data Embedding
Original Image
Encrypted Image
Sub Encrypted Image

5. Proposed Scheme(2/11) ——Data Embedding
Sub_1
Sub_2 13 9 5 1 14 10 6 2
Sub_2
Sub_3
Sub_4
MSB plane of sub_2 ~ 4 1 1 1 15 11 7 3 16 13 8 4
Queue: …
3M*N / 4
Sub_3
Sub_4
Selection key : KSL
Sub Encrypted Image
Queue: …… …… L
(1 < L < 3M*N/4)
Shuffle key : KSF
Queue: …… ……

6. Proposed Scheme(3/11) ——Data Embedding
Queue: …… ……
Divide shuffled bits into K groups, each group contain n bits
K = floor(L/n)
S(1,r) : (1 1 1 … 0 0)
S(2,r) : (0 0 0 … 0 1) …
S(k,r) : (0 1 0 … 0 0) r
C(1,n) : (0 0 1 … 0 0)
C(2,n) : (0 1 1 … 0 1) …
C(k,n) : (0 1 1 … 1 0) n
compressed
H is Sparse parity check matrix size n * r

7. Proposed Scheme(4/11) ——Data Embedding
HT * =
A example of compress

8. Proposed Scheme(5/11) ——Data Embedding
1 0 … 1
1 1 … 0
0 1 … 1
S(1,r) : (1 1 1 … 0 0)
S(2,r) : (0 0 0 … 0 1) …
S(k,r) : (0 1 0 … 0 0) r
C’(1,n) : (1 1 1 … … 1)
C’(2,n) : (0 0 0 … … 0) …
C’(k,n) : (0 1 0 … … 1)
r (n-r)
Embed additional data

9. Proposed Scheme(5/11) ——Virtual Channel and Embedding Rate
Theory:
Check bits r r
Slepian–Wolf theorem DSC and distributed source decoding.
Example:
X,Y is 3 bits message. Constraint of X,Y : Hamming Distance of X,Y less than or equal to 1.
000
001
010
100
Y = r
When X = {0,0,0}
= 2

10. Proposed Scheme(6/11) ——Data Extraction
MSB plane of sub_2 ~ 4
Sub_2
Sub_3
Sub_4 1 1 1
Queue
Encrypted Image
Sub Encrypted Image
Data: …

11. Proposed Scheme(7/11) ——Data Extraction
3M*N / 4
Selection key : KSL
Data: …… …… L
(1 < L < 3M*N/4)
Shuffle key : KSF
Data: …… ……
Divide data into K groups, each group contain n bits
C’(1,n) : (1 1 1 … … 1)
C’(2,n) : (0 0 0 … … 0) …
C’(k,n) : (0 1 0 … … 1)
r (n-r)
Last (n-r) bits in each group is hiding mseeage
1 0 … 1
1 1 … 0
0 1 … 1

12. Proposed Scheme(8/11) ——Image Decryption and Estimation
bilinear interpolation
Encrypted Image
Sub Decrypted Image
reference Image B
Sub_2
Sub_3
Sub_4 14 10 6 2 15 11 7 3 16 13 8 4
optimize
Formula A
Last 7 LSB bits in sub images

13. Proposed Scheme(9/11) ——Image Decryption and Estimation
Optimize formula:
A’ is optimized image
A is decryption image
B is reference image

14. Proposed Scheme(10/11) ——Lossless Recovery
C’(1,n) : (1 1 1 … … 1)
C’(2,n) : (0 0 0 … … 0) …
C’(k,n) : (0 1 0 … … 1)
r (n-r)
S(1,n) : (1 1 1 … 0 0)
S(2,n) : (0 0 0 … 0 1) …
S(k,n) : (0 1 0 … 0 0) r
U(1,n) : (0 0 1 … 0 0)
U(2,n) : (0 1 1 … 0 1) …
U(k,n) : (0 1 1 … 1 0) n
Encrypted Image
reference Image B
Encrypted Image

15. Proposed Scheme(11/11) ——Lossless Recovery
q is error probability of the virtual channel
Distributed source decoding using BPA.

16. Experiment Result(1/4) Image size : 512 * 512
(c) Encrypted image containing secret data
(a) Original Image
(b) Encrypted Image
(d) Recovered Image
Image size : 512 * 512
embedding rate : bpp
(e) Difference between (a) and (d)
(f) Perfectly Recovered Image

17. Experiment Result(2/4)
[7] W. Puech, M. Chaumont, and O. Strauss, “A reversible data hiding method for encrypted images,” Proc. SPIE, Secur., Forensics,Steganogr., Watermarking Multimedia Contents X, vol. 6819, p E,Feb [8] X. Zhang, “Reversible data hiding in encrypted image,” IEEE Signal Process. Lett., vol. 18, no. 4, pp. 255–258, Apr [9] W. Hong, T.-S. Chen, and H.-Y. Wu, “An improved reversible data hiding in encrypted images using side match,” IEEE Signal Process. Lett., vol. 19, no. 4, pp. 199–202, Apr [10] X. Zhang, “Separable reversible data hiding in encrypted image,”IEEE Trans. Inf. Forensics Security, vol. 7, no. 2, pp. 826–832,Apr [12] Z. Qian, X. Han, and X. Zhang, “Separable reversible data hiding in encrypted images by n-nary histogram modification,” in Proc. 3rd Int. Conf. Multimedia Technol. (ICMT), Guangzhou, China, 2013,pp. 869–876.

18. Experiment Result(3/4)
Comparisons of four different approaches using the images. (a) Lena. (b) Baboon. (c) Lake. (d) Man.

19. Experiment Result(4/)
Comparison of approximately recovered image quality in (a) [11] and (b) [13].
[11] K. Ma, W. Zhang, X. Zhao, N. Yu, and F. Li, “Reversible data hiding in encrypted images by reserving room before encryption,”IEEE Trans. Inf. Forensics Security, vol. 8, no. 3, pp. 553–562,Mar [13] W. Zhang, K. Ma, and N. Yu, “Reversibility improved data hiding in encrypted images,” Signal Process., vol. 94, pp. 118–127, Jan

20. Conclusion
This method can achieve higher embedding capacity in encrypted images than other method, and can deal with different key.

21. Thank You