Improved joint reversible data hiding in encrypted images Source: J. Vis. Commun. Image R. 40 (2016) 732–738 Authors: Zhenxing Qian, Shu Dai, Fei Jiang, Xinpeng Zhang Speaker: Lin Jiang-Yi Date: 2017-1-11 前三個作者都是 Information Science and Technology,Sun Yat-sen University, Guangdong,廣東中山大學 Department of Electronics and Computer Engineering,New Jersey Institute of Technology, Newark, NJ 07102, USA

Outline Introduction Proposed Scheme Experimental Results Comments

Introduction（1/6） 1、 reversible data hiding in encrypted images (RDH-EI)

Introduction（2/6） 2、vacating room before encryption (VRBE) 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. 2013. W. Zhang, K. Ma, and N. Yu, Reversibility improved data hiding in encrypted images, Signal Process., vol. 94, no. 1, pp. 118–127, Jan. 2014. Sh. Yi, Y. Zhou, Binary-block embedding for reversible data hiding in encrypted images, Signal Process., vol. 133, pp. 40–51, Apr. 2017.

Introduction（3/6） 3、vacating room after encryption (VRAE) X. Zhang, Reversible data hiding in encrypted images, IEEE Signal Process. Lett., vol. 18, no. 4, pp. 255– 258, Apr. 2011. W. Hong, T. Chen, and H. Wu, An improved reversible data hiding in encrypted images using side match, IEEE Signal Process. Lett., vol. 19, no. 4, pp. 199–202, Apr. 2012. X. Zhang, Separable reversible data hiding in encrypted image, IEEE Trans. Inf. Forensics Security, vol. 7, no. 2, pp. 826–832, Apr. 2012.

Introduction（4/6） 4、Zhang’s method in 2011 Original image s0 s1 145 146 144 147 148 145 146 144 147 148 001 010 000 011 100 Encryption key 3 LSBs Original image s0 s1 Original value Secret=0 Embedding Flip 150 146 151 144 145 149 148 147 110 010 111 000 001 101 100 011 Stego value

Introduction（5/6） 4、Zhang’s method in 2011 Stego value Extraction 150 146 151 144 145 149 148 147 110 010 111 000 001 101 100 011 001 010 000 011 100 145 146 144 147 148 Secret=0 H0 Stego value Secret=1 H1 110 101 111 100 011 150 149 151 153 152 148 147 Extraction

Introduction（6/6） 5、Drawback

Proposed Scheme(1/9) 1、Divide the original image four down-sampled images denoted as E1 , E2 , E3 and E4 .

Proposed Scheme(2/9) 2、 First round embedding Three LSB layers are extracted from E2 , E3 and E4 by Secret: t

Proposed Scheme(3/9) 2、 First round embedding-example 145 146 144 147 148 001 010 000 011 100 L1={(001),(001),(010),(010)} L=4,a=4 … Secret: 2 E2 , E3 and E4 3LSB 146 145 144 147 148 010 001 000 011 100 L1={ (010),(010),(001),(001)} E2’ , E3’ and E4’

Proposed Scheme(4/9) 3、 Second round embedding Three LSB layers are extracted from E1 by swaps the order of W1 and Wr+2 and put the swapped blocks back to the corresponding LSB layers in E1 Secret: r Repeat the embedding until R/2 blocks have been swapped to accommodate additional message

Proposed Scheme(5/9) 3、 Second round embedding-example 145 146 144 147 148 001 010 000 011 100 W1={(001001001000)} Secret: 1 R=4,r=2 W2={(010010000001)} W3={(010011100010)} W4={(010001011001)} 3LSB E1 U1={(010010000001)} 146 147 148 144 145 010 011 100 000 001 U2={(010001011001)} E1’

Proposed Scheme(6/9) 4、 Second round extraction Three LSB layers are extracted from E1’ by swaps the 3LSB of W1’ and Wi+2’,i belongs to [0,R-2],calculate k, and k is the secret. Remove W1’ and Wk+2’ from W set, repeat extraction until the length of J1’ is R/2.

Proposed Scheme(7/9) 4、 Second round extraction-example 146 147 148 144 145 010 011 100 000 001 W1={(010011100010)} Secret: 1 R=4,r=2 W2={(010010000001)} W3={(001001001000)} W4={(010001011001)} E1’ 3LSB 145 146 144 147 148 001 010 000 011 100 E1

Proposed Scheme(8/9) 5、 First round extraction Estimates the other pixels by linear interpolation through E1, create X2,X3 and X4. Divided all pixels in X2,X3 and X4 into L segments{G1,G2,…,GL}。 Divided all pixels in E2’,E3’ and E4’ into L segments{C1,C2,…,CL}。 for i=1:L secret_i = 𝑎𝑟𝑔𝑚𝑖𝑛 𝑘=1 𝑎 | 𝐺 𝑖 𝑘 − 𝐶 𝑖 (𝑘)| end

Proposed Scheme(9/9) 5、 First round extraction-example 146 145 144 147 148 010 001 000 011 100 L1={(010),(010),(001),(001)} L=4,a=4 … E2’ , E3’ and E4’ 145 146 144 147 148 Secret =0 L1’={(010),(010),(001),(001)} , {146,146,145,145} Secret = 1 L1’={(001),(010),(010),(001)} , {145,146,146,145} Secret = 2 L1’={(001),(001),(010),(010)} , {145,145,146,146} … X2 , X3 and X4

Experimental Results(1/5) [3] X. Zhang, Reversible data hiding in encrypted image, IEEE Signal Process. Lett. 18 (4) (2011) 255–258. [4] W. Hong, T.S. Chen, H.Y. Wu, An improved reversible data hiding in encrypted images using side match, IEEE Signal Process. Lett. 19 (4) (2012) 199–202. [5] X. Liao, C.W. Shu, Reversible data hiding in encrypted images based on absolute mean difference of multiple neighboring pixels, J. Vis. Commun. Image Represent. 28 (2) (2015) 21–27. Empirical Chromosomes Addition

Experimental Results(2/5)

Experimental Results(3/5)

Comments RDH-EI in medical images. Suitable for small payload. A little complicate.