New Framework for Reversible Data Hiding in Encrypted Domain Source： IEEE Transactions on Information Forensics and Security , vol.11, no.12, pp: 2777-2789, 2016. Authors：Fangjun Huang, Jiwu Huang, Yun-Qing Shi Speaker ：Xiaozhu Xie Date ： 2017/01/19

Outline Motivation Proposed scheme Experimental results Conclusions I will present in four parts. So first let us turn to introduction.

Correlation between the neighboring pixels does not exist any more. Motivation(1/2) RDH methods in plain images(PI) (Original) histogram shifting(HS) Difference histogram shifting(DHS) Prediction-error histogram shifting(PEHS) RDH in encrypted images. Correlation between the neighboring pixels does not exist any more. … Simple computation. High embedding capacity. Good visual quality.

Motivation(2/2) Specific encryption algorithm is designed. Preserve the correlation between the neighboring pixels. 本Paper的motivation Therefore, this paper proposes a novel framework for reversible data hiding in encrypted image (RDH-EI) based on reversible image transformation (RIT).

Proposed scheme(1/6)- Specific encryption algorithm Original Image I 154 155 158 10011010 10011011 10011110 10011110   ⨁ Original sub-block key1 10010111 10001100 … 00110100 𝑅 1 𝑅 2 𝑅 𝑁 … 13 12 9 00001101 00001100 00001001 00001001 N non-overlapping blocks Encrypted sub-block Step 1: Specific stream encryption. Step 2: Permutation. key2 Permute all the N encrypted sub-blocks.

Proposed scheme(2/6)-Preservation of Statistical Characteristics Two neighboring pixels: (𝑃 𝑖,𝑥 , 𝑃 𝑖,𝑦 ) Case 1: 𝑃 𝑖,𝑦 − 𝑃 𝑖,𝑥 =0 , difference remains 0 after encryption. Case 2: 𝑃 𝑖,𝑦 − 𝑃 𝑖,𝑥 =−1. Case 3: 𝑃 𝑖,𝑦 − 𝑃 𝑖,𝑥 =1 {(𝛼,𝛼+1)|0≤𝛼≤254} 255 different pixel pairs. K=0 𝑃 𝑖,𝑥 =01111111 𝑃 𝑖,𝑦 =11111111 K=1 𝑃 𝑖,𝑥 =00111111 𝑃 𝑖,𝑦 =01111111 𝑃 𝑖,𝑥 =10111111 𝑃 𝑖,𝑦 =11111111 K=2 𝑃 𝑖,𝑥 =00011111 𝑃 𝑖,𝑦 =00111111 𝑃 𝑖,𝑥 =01011111 𝑃 𝑖,𝑦 =01111111 𝑃 𝑖,𝑥 =10011111 𝑃 𝑖,𝑦 =10111111 𝑃 𝑖,𝑥 =11011111 𝑃 𝑖,𝑦 =11111111 K=3,…,7 …

Proposed scheme(3/6)- Preservation of Statistical Characteristics 𝑁 #1 : Number of original pixel pairs with difference value 1. 𝑁 𝐸 #1 : Number of encrypted pixel pairs with difference value 1. K=7 𝑃 𝑖,𝑥 = 𝑏 1 𝑏 2 𝑏 3 𝑏 4 𝑏 5 𝑏 6 𝑏 7 0 𝑃 𝑖,𝑦 = 𝑏 1 𝑏 2 𝑏 3 𝑏 4 𝑏 5 𝑏 6 𝑏 7 1 𝑅 𝑖 ⨁ Difference 1,-1 K=6 𝑃 𝑖,𝑥 = 𝑏 1 𝑏 2 𝑏 3 𝑏 4 𝑏 5 𝑏 6 01 𝑃 𝑖,𝑦 = 𝑏 1 𝑏 2 𝑏 3 𝑏 4 𝑏 5 𝑏 6 10 3,-3,1,-1 … Assumption: Key stream bits are uniformly distributed. The difference may remain 1 or be changed to -1, with 50 percentage, respectively .

Proposed scheme(4/6)-Preservation of Statistical Characteristics Deduce : At least 1 3 𝑁 #1 pixel pairs’ difference remains 1, and 1 3 𝑁 #1 of them will change to -1. After encryption, the neighboring pixel pairs with the difference value 0 are preserved, and more than 2/3 pixel pairs with the difference values 1 and -1 are still preserved.

Proposed scheme(5/6)- DHS embedding   𝑪 𝒊,𝟏 𝑪 𝒊,𝟐 𝑪 𝒊,𝟑 𝑪 𝒊,𝟒 Overflow/ underflow 𝑪 𝒊,𝟏 ′ 𝑪 𝒊,𝟐 ′ 𝑪 𝒊,𝟑 ′ 𝑪 𝒊,𝟒 ′ 𝑪 𝒊,𝟏 ′ 𝑫 𝒊,𝟐 𝑫 𝒊,𝟑 𝑫 𝒊,𝟒 𝑪 𝒊,𝟏 ′ 𝑪 𝒊,𝟐 ′′ 𝑪 𝒊,𝟑 ′′ 𝑪 𝒊,𝟒 ′′ b: bit to be embedded. Encrypted sub-block preprocessed sub-block Difference sub-block Marked sub-block Encrypted image (Location map L will also be embedded.) Procedure of DHS embedding   253 255 252 253 254 252 253 1 -1 253 255 254 252 Secret message: 10 Encrypted sub-block preprocessed sub-block Difference sub-block Marked sub-block Encrypted image Example of DHS embedding

Proposed scheme(6/6)- DHS extraction & recovery   253 255 254 252 Extraction Secret message: 10 Marked image Marked sub-block Location map L Recovery 253 254 252 253 255 252 Key 1 154 155 158 Key 2 Original image permute Encrypted sub-block Original sub-block Example of DHS extraction & recovery

Experimental Results(1/5) Different sub-blocks of the encrypted image. (a) DHS_1. (b) DHS_2. (c) DHS_3. Three prediction algorithms. (a) MED. (b) GAP. (c) rhombus. (a) PEHS_1. (b) PEHS_2. (c) PEHS_3. PEHS_1: M. J. Weinberger, G. Seroussi, and G. Sapiro, “The LOCO-I lossless image compression algorithm: Principles and standardization into JPEG-LS,” IEEE Trans. Image Process., vol. 9, no. 8, pp. 1309–1324, Aug. 2000. PEHS_2: X.Wu and N. Memon, “Context-based, adaptive, lossless image coding,” IEEE Trans. Commun., vol. 45, no. 4, pp. 437–444, Apr. 1997 PEHS_3: B. Ou, X. Li, Y. Zhao, R. Ni, and Y.-Q. Shi, “Pairwise predictionerror expansion for efficient reversible data hiding,” IEEE Trans. Image Process., vol. 22, no. 12, pp. 5010–5021, Dec. 2013.

Experimental Results(2/5) Look like Mosaic [moʊˈzeɪɪk] images.

Experimental Results(3/5)

Experimental Results(4/5)

Experimental Results(5/5) Zhang [12]: X. Zhang, “Reversible data hiding in encrypted image,” IEEE Signal Process. Lett., vol. 18, no. 4, pp. 255–258, Apr. 2011. Zhang [14]: X. Zhang, “Separable reversible data hiding in encrypted image,”IEEE Trans. Inf. Forensics Security, vol. 7, no. 2, pp. 826–832, Apr. 2012.

Conclusions Present a new framework which allows the numerous RDH schemes developed before for non-encrypted images be conducted in the encrypted domain directly. A new specific stream encryption algorithm is proposed to preserve some correlation between the neighboring pixels.

Thank you!