Information Hiding Technology: Current Research and Future Trend Chair Professor Chin-Chen Chang (張真誠) National Tsing Hua University (清華大學) National Chung Cheng University (中正大學) Feng Chia University (逢甲大學) http://msn.iecs.fcu.edu.tw/~ccc

Watermarking Image authentication Secret sharing Visual cryptography Steganography Future Trend

Watermarking Visible watermarking Easy to embed Clear to see watermark

Watermarking (Cont.) Invisible watermarking Requirements: Good visual quality of watermarked image Robustness Watermarking Original image Watermarked image Watermark

Image authentication Requirements: Detect the tampered area Try to restore the tampered area Image Tampered image Detected image Restored image

Secret sharing Classification: Meaningless shadows Meaningful shadows

Secret sharing (Cont.) Sharing Shadow size: 256  256 Reconstructing Image size: 512  512 Reconstructing (2,4)-threshold secret sharing scheme PSNR=24 dB

Secret sharing (Cont.) Reconstructing Secret image Hiding Stego-image Reconstructed secret image Secret image Stego-image (2, n)-threshold secret sharing scheme Stego-image

Visual cryptography Stacking Shadow 1 Shadow 2 Secret

Visual cryptography (Cont.) Stacking Shadow 1 Shadow 2 Secret

Visual cryptography (Cont.) Rotating 40o Stacking Stacking Share 1 Share 2 Secret 1 “VISUAL” Secret 2 “SECRET”

Steganography The targets Restoration Frequency domain (e.g. DCT, DWT, DFT) Spatial domain (e.g. pixel values) Compression domain (e.g. VQ) Text Restoration Irreversible Reversible

Steganography (Cont.) Image Hiding system Stego image Cover image Secret message Stego image 1 0 1 0 1 0 0 1 0 1 1 1 1 0 0

Steganography (Cont.) Cover Carriers Image Video Sound Text

Steganography (Cont.) Text Video Sound 壞的毛病 壞毛病 山東的蘋果 山東蘋果 我的媽媽 我媽媽 壞的毛病 壞毛病 山東的蘋果 山東蘋果 我的媽媽 我媽媽 主要的問題 主要問題 另外的一件事 另外一件事 其他的問題 其他問題 北京的大學 北京大學 Video Sound

Zhang and Wang’s Method (Embedding) 8 7 9 4 79 54 55 11 20 21 12 24 10 Secret data: 1000 1011… p2 255 1 2 3 4 1 2 3 4 1 : : : : : : : : : : : : : 10002 1 35 … 11 2 3 4 1 2 3 4 1 2 3 2 … 10 1 2 3 4 1 2 3 4 1 Cover image … 9 3 4 1 2 3 4 1 2 3 4 3 … 8 1 2 3 4 1 2 3 4 1 2 1 … 7 4 1 2 3 4 1 2 3 4 4 … 6 2 3 4 1 2 3 4 1 2 3 2 … 5 1 2 3 4 1 2 3 4 1 7 10 4 … 4 3 4 1 2 3 4 1 2 3 4 3 … 3 1 2 3 4 1 2 3 4 1 2 1 … 2 4 1 2 3 4 1 2 3 4 4 … 1 2 3 4 1 2 3 4 1 2 3 2 … 1 2 3 4 1 2 3 4 1 Stego image 1 2 3 4 5 6 7 8 9 10 11 … 255 p1 Magic Matrix

Zhang and Wang’s Method (Extracting) p2 7 10 4 255 1 2 3 4 1 2 3 4 1 : : : : : : : : : : : : : … 11 2 3 4 1 2 3 4 1 2 3 2 … 10 1 2 3 4 1 2 3 4 1 … 9 3 4 1 2 3 4 1 2 3 4 3 … 8 1 2 3 4 1 2 3 4 1 2 1 Stego image … 7 4 1 2 3 4 1 2 3 4 4 … 6 2 3 4 1 2 3 4 1 2 3 2 … 5 1 2 3 4 1 2 3 4 1 … 4 3 4 1 2 3 4 1 2 3 4 3 … 3 1 2 3 4 1 2 3 4 1 2 1 … 2 4 1 2 3 4 1 2 3 4 4 1 35 … 1 2 3 4 1 2 3 4 1 2 3 2 … 1 2 3 4 1 2 3 4 1 p1 1 2 3 4 5 6 7 8 9 10 11 … 255 Extracted secret data: 10002 Magic Matrix

Sudoku A logic-based number placement puzzle

Sudoku (Cont.) Property A Sudoku grid contains nine 3 × 3 matrices, each contains different digits from 1 to 9. Each row and each column of a Sudoku grid also contain different digits from 1 to 9. Possible solutions: 6,670,903,752,021,072,936,960 (i.e. ≈ 6.671×1021)

Data Hiding Using Sudoku - 1 Reference Matrix M

Data Hiding Using Sudoku (Embedding) (Cont.) 8 7 11 12 79 54 55 20 21 24 10 9 Secret data: 011 001 10… 279 Cover Image min. d( , ) = ((8-8)2+(4-7)2)1/2=3 d( , ) = ((9-8)2+(7-7)2)1/2=1 d( , ) = ((6-8)2+(8-7)2)1/2=2.24 9 7 Stego Image

Data Hiding Using Sudoku (Embedding) (Cont.) 8 7 11 12 79 54 55 20 21 24 10 9 Secret data: 011 001 10… 279 Cover Image d( , ) = ((11-11)2+(15-12)2)1/2=3 d( , ) = ((15-11)2+(12-12)2)1/2=4 d( , ) = ((9-11)2+(14-12)2)1/2=2.83 min. 9 7 14 Stego Image

Data Hiding Using Sudoku (Extracting) (Cont.) 9 7 14 Stego Image Extracted data: 279 = 011 0012

Experimental Results

Experimental Results (Cont.) The results of visual quality and Embedding capacity comparisons Images Proposed PSNR C Baboon Barbara Boats Goldhill Jet(F16) Lena Pepper Sailboat Tiffany 44.68 44.77 44.94 44.84 45.02 44.97 44.67 1.5 Average 44.88

Future Trends Reversible Data Hiding in Compressed Images VQ Compressed Images JPEG Images SMVQ Compressed Images

Future Trends (Cont.) Reversible Data Hiding in Encrypted Images (e) Decrypted image (right key) (d) Marked image (1.0bpp) (f) Decrypted image (wrong key)

Future Trends (Cont.) Reversible Data Hiding in Error Control Codes QR Codes (a) (b) (c)

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