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
Examples of Digital Signature
Possible Scenarios During the Authentication Process
Parent-children Pair
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
Ex. Results
Ex. Results
Ex. Results
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.