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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 - PowerPoint PPT Presentation
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Recent Developments on Multimedia and Secure
Networking Technologies
Chair Professor Chin-Chen ChangFeng Chia UniversityNational Chung Cheng University National Tsing Hua University
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Multimedia (Watermarking) Classifications:
Visible watermarking Invisible watermarking Robust watermarking Semi-fragile watermarking Fragile watermarking
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Multimedia (Watermarking) (Cont.) Visible watermarking
Easy to embed Clear to see watermark
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Multimedia (Watermarking) (Cont.) Invisible watermarking
Requirements: Good visual quality of watermarked image Robustness
Watermarking
Watermarked imageOriginal imageWatermark
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Multimedia (Image authentication) Requirements:
Detect the tampered area Try to restore the tampered area
Solutions: Hamming codes
Image Tampered image Detected image Restored image
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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
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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
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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 …
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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
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Multimedia (Secret sharing) (Cont.)
Shadow size: 256 256Image size: 512 512
Sharing
Reconstructing
PSNR=24 dB
(2,4)-threshold secretsharing scheme
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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
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Multimedia (Secret sharing) (Cont.)
Secret image
Stego-image
Stego-image
Hiding
Reconstructed secret image
Reconstructing
(n,2)-threshold secretsharing scheme
Stego-image
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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
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Multimedia (Visual cryptography) (Cont.)
Shadow 1 Shadow 2
Secret
Staking
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Multimedia (Visual cryptography) (Cont.)
Shadow 1 Shadow 2
Secret
Staking
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Multimedia (Visual cryptography) (Cont.)
Share 1 Share 2
Secret 1 “VISUAL” Secret 2 “SECRET”
Staking Staking
Rotating 40o
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Multimedia (Threshold) Requirements:
Segment the objects on image Low computation cost
Original image Segmented image
Threshold value T=53
Histogram
Class 2Class 1
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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
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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)
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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
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Secure Networking (Cont.) Authentication in WLAN
Requirements: Prevent impersonation attacks Protect personal privacy
Solutions: Using mutual authentication Feasible computational complexity Using session keys
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Secure Networking (Cont.) Key Exchange
2. Service request1. Issue an IC card
Users
Authentication Center (AC)IC Card Issuing Center
Remote Server
3. Authentication and key exchange
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Secure Networking (Cont.) Requirements:
Freely choose identity and password Password modification Mutual authentication Common session key distribution Reduce computation cost
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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
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