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Recent Developments on Multimedia and Secure Networking Technologies. Chair Professor Chin-Chen Chang Feng Chia University National Chung Cheng University National Tsing Hua University. Multimedia (Watermarking). Classifications: Visible watermarking Invisible watermarking
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Recent Developments on Multimedia and Secure Networking Technologies Chair Professor Chin-Chen Chang Feng Chia University National Chung Cheng University National Tsing Hua University
Multimedia (Watermarking) • Classifications: • Visible watermarking • Invisible watermarking • Robust watermarking • Semi-fragile watermarking • Fragile watermarking
Multimedia (Watermarking) (Cont.) • Visible watermarking • Easy to embed • Clear to see watermark
Multimedia (Watermarking) (Cont.) • Invisible watermarking • Requirements: • Good visual quality of watermarked image • Robustness Watermarking Original image Watermarked image Watermark
Multimedia (Image authentication) • Requirements: • Detect the tampered area • Try to restore the tampered area • Solutions: • Hamming codes Tampered image Detected image Restored image Image
Multimedia (Steganography) • Classification: • The target of modification • Frequency domain (e.g. DCT, DWT, DFT) • Spatial domain (e.g. pixel values) • Compression domain (e.g. VQ, LAC, SOC) • Stego image restoration • Irreversible data hiding • Reversible data hiding
Multimedia (Steganography) (Cont.) • Irreversible data hiding • Requirements: • High capacity • Good visual quality of stego images • Solutions: • Using Sudoku • Using wet paper codes concept • Using Hamming codes
Multimedia (Steganography) (Cont.) • Reversible • Requirements: • Fully reconstructing cover image • Good visual quality of stego image • High capacity • Solutions: • Data hiding in VQ indices • Data hiding in LAC codes • Data hiding in SOC codes • …
Multimedia (Secret sharing) • Classification: • Meaningless shadows • Meaningful shadows • Meaningless shadows • Requirements: • Unexpected user can not see the secret image • Good visual quality of reconstructed secret image
Multimedia (Secret sharing) (Cont.) Sharing Shadow size: 256 256 Image size: 512 512 Reconstructing (2,4)-threshold secret sharing scheme PSNR=24 dB
Multimedia (Secret sharing) (Cont.) • Meaningful shadows • Requirements: • Good visual quality of stego image • Secret image extraction and reconstruction • Solutions: • Applying steganography techniques • Applying image authentication mechanisms
Multimedia (Secret sharing) (Cont.) Reconstructing Hiding Stego-image Reconstructed secret image Secret image Stego-image (n,2)-threshold secret sharing scheme Stego-image
Multimedia (Visual cryptography) • Requirements: • Secret message delivery • Unexpected user can not see the message from an individual share • Solutions: • Using shadow patterns • Using meaningful shadow images • Using Circle Shares
Multimedia (Visual cryptography) (Cont.) Staking Shadow 1 Shadow 2 Secret
Multimedia (Visual cryptography) (Cont.) Staking Shadow 1 Shadow 2 Secret
Multimedia (Visual cryptography) (Cont.) Rotating 40o Staking Staking Share 2 Share 1 Secret 1 “VISUAL” Secret 2 “SECRET”
Multimedia (Threshold) • Requirements: • Segment the objects on image • Low computation cost Threshold value T=53 Class 1 Class 2 Original image Segmented image Histogram
Secure Networking • Fast Computation Algorithms for Cryptography • Requirements: • Large number computations • Low computation cost • Solutions: • Fast division algorithm using residue number system (RNS) • Fast conversion algorithms in RNS using Aryabhata remainder theorem (ART) • Fast RNS modular multiplication and exponentiation algorithms
Secure Networking (Cont.) • Secure Communication • Secure E-mail protocols • Requirements • Reduce the computation cost of client devices • Achieve perfect forward secrecy • Solutions: • Using low cost functions (e.g. one-way hash functions)
Secure Networking (Cont.) • Anonymity for Roaming Service • Requirements: • Avoid possible attacks (e.g. replay attacks, forgery attacks, known-key attacks) • Achieve the property of anonymity • Solutions: • Using low cost functions • Using smart card • Using nonce to replace timestamp
Secure Networking (Cont.) • Authentication in WLAN • Requirements: • Prevent impersonation attacks • Protect personal privacy • Solutions: • Using mutual authentication • Feasible computational complexity • Using session keys
Secure Networking (Cont.) • Key Exchange Remote Server Authentication Center (AC) IC Card Issuing Center 2. Service request 3. Authentication and key exchange 1. Issue an IC card Users
Secure Networking (Cont.) • Requirements: • Freely choose identity and password • Password modification • Mutual authentication • Common session key distribution • Reduce computation cost
Secure Networking (Cont.) • E-commerce Application • Electronic check • Payer’s identity appending • E-checks generation • Payer and payee verification • E-traveler’s check • Unique identity for the e-traveler’s check • E-traveler’s check can only be generated by check –issuing bank or an authorized organization