Chair Professor Chin-Chen Chang Feng Chia University Security Technologies on Communication Networks and Their Applications to Electronic Business Chair Professor Chin-Chen Chang Feng Chia University National Chung Cheng University National Tsing Hua University http://msn.iecs.fcu.edu.tw/~ccc

Outline Mobile services Radio Frequency Identification (RFID) Roaming between cellular network and WLAN Watermarking Image authentication Visual cryptography Secret sharing Steganography MSN lab

Mobile services (1/4) MSN lab

Mobile services (2/4) MSN lab

Mobile services (3/4) MSN lab

Treats ? (4/4) User perspective Network perspective Spoofing Framing Denial-of-service Network perspective Passive Active 1. Eavesdropping 2. Traffic analysis 1. Masquerading 2. Replay 3. Message modification MSN lab

Spoofing MSN lab

Framing Legitimate? Bogus? MSN lab

Denial-of-service MSN lab

RFID (1/4) Tag Reader Database Antenna MSN lab

RFID (2/4) Shopping Library Transportation Household appliance … MSN lab

Risk? (3/4) Eavesdropping Traffic analysis Replay attack Position detection Physical attack MSN lab

Issue? (4/4) Anonymity -> Privacy Synchronization Authentication Efficiency MSN lab

Roaming (1/3) Access to the Internet anywhere & anytime Mobile device Base station AP AS ISP WLAN Cellular network AS: Authentication server AP: Access point MSN lab

Roaming (2/3) Cellular networks : wide service areas and continuous pervasive access WLAN : high-speed pervasive communications How to integrate? MSN lab

Issues? (3/3) Mutual authentication Anonymous service Charging MSN lab

Watermarking Visible watermarking Easy to embed Clear to see watermark MSN lab

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

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

Classification: Meaningless shadows Meaningful shadows Secret sharing MSN lab

Secret sharing (Cont.) Sharing Shadow size: 256  256 Reconstructing Image size: 512  512 Reconstructing (2,4)-threshold secret sharing scheme MSN lab 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 MSN lab

Visual cryptography Stacking Shadow 1 Shadow 2 Secret MSN lab

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

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

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 MSN lab

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 MSN lab

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 MSN lab

Conclusions The biggest risk: eavesdropping & copy The limitation: Power Computing capability Robustness Image quality MSN lab

Security Technologies on Communication Networks and Their Applications to Electronic Business MSN lab