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Structural Digital Signature for Image Authentication: An Incidental Distortion Resistant Scheme. Source: IEEE Transactions on Multimedia, Vol. 5, No. 2, pp. 161-173, 2003 Authors: Chun-Shien Lu and Hong-Yuan Mark Liao Reporter: Jen-Bang Feng. Outline. Digital Signature
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Structural Digital Signature for Image Authentication: An Incidental Distortion Resistant Scheme Source: IEEE Transactions on Multimedia, Vol. 5, No. 2, pp. 161-173, 2003 Authors: Chun-Shien Lu and Hong-Yuan Mark Liao Reporter: Jen-Bang Feng
Outline • Digital Signature • Scenarios During the Authentication Process • SDS Based on Interscale Relation of Wavelet Coefficients • Ex. Results • Discussions • Conclusions
Structural Digital Signature (SDS) • Parent-children pair in Wavelet Trans. SDS(I): 0 <= i,j <= 1, o is the position index
Structural Digital Signature (SDS) Symbol I: p > 0, c > 0 Symbol II: p > 0, c < 0 Symbol III: p < 0, c > 0 Symbol IV: p < 0, c < 0 Record the Symbols as the signature
Verification Completeness of SDS:
Ex. Results 22~4 scales when σ = 256 22~4 scales when σ = 128
Ex. Results 22~4 scales when σ = 256 22~4 scales when σ = 128
Discussions • Num. of scales • Complexity • False Positive & False Negative • Relation between σ and robustness • Relation between σ and sensitivity • If image intensity is changed • If the selected parent-children pair are known and changed
Conclusions • Threshold value determines the size of the authentication message. • Malicious tampering is distinguished from incidental modifications. • Tampered regions are localized. • The recovery of the tampered region is not provided.