Separable and error-free reversible data hiding in encrypted images Source：Signal Processing, 2016, 123:9-21. Authors： DawenXu, RangdingWang Speaker ：Xiaozhu Xie Date ： 2018/03/29

Outline Scenario Proposed scheme Experimental results Conclusions I would like to present in these five parts.

Scenario Embed additional messages(e.g.,labels, time stamps, category information etc.) KEMB KENC KENC [səˈnærioʊ] cloud storage is becoming more and more popular, I bet everyone here uses cloud storage more or less. However the security problem followed. For example, many photos of Hollywood actresses leaked from iCloud two years ago. So before upload the images, we would like to encrypt it. And on the server side, cloud server would like to embed some information for management, for example…. So

Proposed scheme(1/13) SP NSP

Proposed scheme(2/13)-Generation of interpolation-error SP NSP [23] L.X. Luo, Z.Y.Chen, M.Chen, Reversible image watermarking using interpolation technique, IEEE Trans.Inf.Forensics Secur.5(1)(2010) 187–193.

Proposed scheme(3/13)-Generation of interpolation-error 90 28 30 … 98 100 32 24 86 90 59 28 29 30 … 98 79 64 48 31 99 100 66 32 61 77 93 65 24 55 86 92 90 1 28 21 30 … -2 16 4 9 98 -1 100 -16 32 -31 19 11 24 -15 86 Original Image Down-sample pixels Interpolation Interpolation-errors 𝐸(𝑖,𝑗) -127 ~ +127

Proposed scheme(4/13)-Image encryption 124 1 245 34 21 … -2 23 7 65 42 -1 154 -45 230 -34 12 43 25 -32 189 SP: Bitwise XOR with random bit stream generated by 𝐾 𝑒𝑛 . NSP(𝐸(𝑖,𝑗)): As follows. The encrypted image ( 𝑇 𝑛 =−2, 𝑇 𝑝 =1) 𝐸 ′ 𝑖,𝑗 = 𝐸(𝑖,𝑗) 𝑖𝑓 𝐸(𝑖,𝑗)∈ 𝑇 𝑛 , 𝑇 𝑝 𝑚𝑜𝑑 𝐸 𝑖,𝑗 − 𝑇 𝑝 +1 + 𝑟 1 𝑖,𝑗 , 127−2 𝑇 𝑝 +1 +1 +( 𝑇 𝑝 +1) 𝑖𝑓 𝐸(𝑖,𝑗)∈ 𝑇 𝑝 +1,127−( 𝑇 𝑝 +1) −𝑚𝑜𝑑 𝑟 2 𝑖,𝑗 − 𝐸 𝑖,𝑗 − 𝑇 𝑛 −1 , 127+2 𝑇 𝑛 +( 𝑇 𝑛 −1) 𝑖𝑓 𝐸(𝑖,𝑗)∈ −127−𝑇 𝑛 , 𝑇 𝑛 −1 Random numbers: 𝑟 1 (𝑖,𝑗)∈ 0,127−2( 𝑇 𝑝 +1) , 𝑟 2 (𝑖,𝑗)∈ 0,127+ 𝑇 𝑛 +( 𝑇 𝑝 −1)

Proposed scheme(5/13)

Proposed scheme(6/13)-Data embedding 124 1 245 34 21 … -2 23 7 65 42 -1 154 -45 230 -34 12 43 25 -32 189 124 3 245 36 21 … -4 25 9 67 42 -2 154 -47 230 -36 14 1 45 27 -34 189 10010 𝑇 𝑛 =−2, 𝑇 𝑝 =1 The encrypted image The marked encrypted image 𝑤 is the to-be-embedded bit

Proposed scheme(7/13)-Data extraction and image recovery

Proposed scheme(8/13)-Scheme I (data extraction) 124 3 245 36 21 … -4 25 9 67 42 -2 154 -47 230 -36 14 1 45 27 -34 189 10010 Data extraction: 𝑤 = 𝐸 𝑖,𝑗 𝑚𝑜𝑑 2 𝐸 𝑖,𝑗 ∈ 2 𝑇 𝑛 , 2 𝑇 𝑝 +1 The marked encrypted image

Proposed scheme(9/13)-Scheme I (Image recovery) 124 3 245 36 21 … -4 25 9 67 42 -2 154 -47 230 -36 14 1 45 27 -34 189 1 36 … -2 25 9 67 -1 -47 -36 14 45 27 -34 1 21 … -2 16 4 9 -1 -16 -31 19 11 -15 𝑟 1 𝑖,𝑗 𝑟 2 𝑖,𝑗 The marked encrypted image 𝑋 𝑖,𝑗 ∈𝑆𝑃:⨁ 𝐾 𝑒𝑛 𝑋′(𝑖,𝑗)∈𝑁𝑆𝑃 : interpolation 90 59 28 29 30 … 98 79 64 48 31 99 100 66 32 61 77 93 65 24 55 86 92 𝑋 𝑖,𝑗 = 𝑋 ′ 𝑖,𝑗 +𝐸(𝑖,𝑗).

Proposed scheme(10/13)-Scheme I (Image recovery)

Proposed scheme(11/13)-Scheme II (Image decryption) 124 3 245 36 21 … -4 25 9 67 42 -2 154 -47 230 -36 14 1 45 27 -34 189 3 23 … -4 18 6 11 -2 -18 -33 21 1 13 -17 𝑟 1 𝑖,𝑗 𝑟 2 𝑖,𝑗 The marked encrypted image 𝑋 𝑖,𝑗 ∈𝑆𝑃:⨁ 𝐾 𝑒𝑛 𝑋′(𝑖,𝑗)∈𝑁𝑆𝑃 : interpolation 90 59 28 29 30 … 98 79 64 48 31 99 100 66 32 61 77 93 65 24 55 86 92 90 62 28 52 30 … 94 97 70 54 42 98 100 48 32 92 86 24 38 The marked decrypted image

Proposed scheme(12/13)-Scheme II (Image decryption)

Proposed scheme(13/13)-Scheme II (data extraction and image recovery) 90 62 28 52 30 … 94 97 70 54 42 98 100 48 32 92 86 24 38 3 23 … -4 18 6 11 -2 -18 -33 21 1 13 -17 10010 The marked decrypted image 𝑋′(𝑖,𝑗)∈𝑁𝑆𝑃 : interpolation 1 21 … -2 16 4 9 -1 -16 -31 19 11 -15 90 59 28 29 30 … 98 79 64 48 31 99 100 66 32 61 77 93 65 24 55 86 92 The original image

Experimental results (1/5)

Experimental results (2/5)

Experimental results (3/5)

Experimental results (4/5)

Experimental results (5/5) [20] W.M.Zhang,K.D.Ma,N.H.Yu, Reversibility improved data hiding in encrypted images, Signal Process. 94 (2014) 118–127. [21]X.C.Cao, L.Du, X.X.Wei, D.M.Meng, X.J.Guo, High capacity reversible data hiding in encrypted images by patch-level sparse representation, IEEE Trans. Cybern., no.99, pp.11.

Conclusions Separable. The hidden data can be extracted either in encrypted or decrypted domain.

Thank you!