1. Recent Developments on Multimedia and Secure Networking Technologies
Chair Professor Chin-Chen Chang
Feng Chia University
National Chung Cheng University
National Tsing Hua University

2. Multimedia (Watermarking)
Classifications:
Visible watermarking
Invisible watermarking
Robust watermarking
Semi-fragile watermarking
Fragile watermarking

3. Multimedia (Watermarking) (Cont.)
Visible watermarking
Easy to embed
Clear to see watermark

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

5. Multimedia (Image authentication)
Requirements:
Detect the tampered area
Try to restore the tampered area
Solutions:
Hamming codes
Image
Tampered image
Detected image
Restored image

6. 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

7. 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

8. 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 …

9. Multimedia (Secret sharing)
Classification:
Meaningless shadows
Meaningful shadows
Requirements:
Unexpected user can not see the secret image
Good visual quality of reconstructed secret image

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

11. 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

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

13. 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

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

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

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

17. Multimedia (Threshold)
Requirements:
Segment the objects on image
Low computation cost
Threshold value T=41
Class 1
Class 2
Original image
Segmented image
Histogram

18. 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

19. Secure Networking (Cont.)
Secure Communication
Secure protocols
Requirements
Reduce the computation cost of client devices
Achieve perfect forward secrecy
Solutions:
Using low cost functions (e.g. one-way hash functions)

20. 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

21. Secure Networking (Cont.)
Authentication in WLAN
Requirements:
Prevent impersonation attacks
Protect personal privacy
Solutions:
Using mutual authentication
Feasible computational complexity
Using session keys

22. Secure Networking (Cont.)
Key Exchange
Remote Server
IC Card Issuing Center
Authentication Center (AC)
2. Service request
3. Authentication and key exchange
1. Issue an IC card
Users

23. Secure Networking (Cont.)
Requirements:
Freely choose identity and password
Password modification
Mutual authentication
Common session key distribution
Reduce computation cost

24. 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