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Explore joint authentication and authenticity protection for multimedia over wireless networks. Learn about unequal protection techniques and evaluation methods.
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Joint Source-Channel-Authentication Resource Allocation and Unequal Authenticity Protection for Multimedia Over Wireless Networks • Zhi Li, Qubin Sun, Yong Lian and Chang Wen Chen • IEEE TRANSACTIONS ON MULTIMEDIA, 2007 Computer Architecture Lab. Hanbit Kim 2008. 12. 9
Contents • Introduction • Motivation • Basic Concept • System Overview • Joint source-channel-authentication • Unequal authenticity protection • Evaluation • Conclusion • Discussion
Introduction • Authenticating multimedia data over wireless networks • Sample products • Medical images • Portraits of criminal suspects
Motivation Sender Receiver 11110101010 11100010101 10010100011 11110100010 11100010101 10010100011 Authentication Fail!! Send Exe file Packet loss Bit error Sender Receiver Authentication Fail!! Send • Is it reasonable? Multimedia file
Basic Concept • Content-awareness framework • Optimizing end-to-end quality • Considering source coding, channel coding and authentication together • Differentiating the importance of packet
Basic Concept Before After After
Joint Source-Channel-Authentication • Optimization • Minimizing end-to-end distortion • Maximizing an authentication probability • Dopt= minrsrc(Ds,opt(rs) + Dca,opt(Eopt(e(rc),m(rs,rc)), e(rc))) • rs + rc <= 1
Joint Source-Channel-Authentication • Source coding model • R-D relationship • Channel model • e = 1 - (1 - εd)lp • Authentication model • Unequal authenticity protection (UAP)
Unequal Authenticity Protection • Signature amortization through hash-chaining (SAHC) • Sign only one packet.
Unequal Authenticity Protection • Authentication probability (AP) • How likely a packet is verifiable. • Authentication graph (AG)
Unequal Authenticity Protection • Multi-layer unequal chaining (MUC)
Unequal Authenticity Protection • Optimal bit allocation • Select the number of layers for MUC AG. • Select the number of pilot packets • Sort and assign the packets to pilot packets according to the weight. • Compute the maximum Σ weight * APs.
Evaluation End-to-end R-D curve
Conclusion • Content-aware stream-level approach • Novel concept of UAP • Joint overall
Discussion • Work on JPEG only • Computation overhead