A Semi-Fragile Watermarking Scheme Using Weighted Vote with Sieve and Emphasis for Image Authentication

Nozomi ISHIHARA  Koki ABE  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E90-A   No.5   pp.1045-1054
Publication Date: 2007/05/01
Online ISSN: 1745-1337
DOI: 10.1093/ietfec/e90-a.5.1045
Print ISSN: 0916-8508
Type of Manuscript: PAPER
Category: Information Security
watermarking,  DWT,  semi-fragile,  authentication,  tamper-proofing,  

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This paper describes a semi-fragile watermarking scheme for image authentication and tamper-proofing. Each watermark bit is duplicated and randomly embedded in the original image in the discrete wavelet domain by modifying the corresponding image coefficients through quantization. The modifications are made so that they have little effect on the image and that the watermarking is robust against tampering. The watermark image for authentication is reconstructed by taking a weighted vote on the extracted bits. The bits that lose the vote are treated as having been tampered with, and the locations of the lost bits as indicating tampered positions. Thus, authentication and tamper-proofing can be done by observing the images of watermarks that win and lose votes. Sieving, emphasis, and weighted vote were found to be effectively make the authentication and tamper detection more accurate. The proposed scheme is robust against JPEG compression or acceptable modifications, but sensitive to malicious attacks such as cutting and pasting.