Content-based Authentication using Hash Function in Digital Images

H. Lim, M.E. Lee, S.Y. Park, and W.H. Cho (Korea)


Watermarking, Contentbased Authentication, Imagedescription vector, Hash Function


In this paper, we present a content-based secure authentic watermarking technique using a hash function in digital images. To generate the secure and content-based watermark, a Hopfield network is first employed on the edge patterns and then the extracted digest vectors of the image are inputted to the Hash function for a seed value of a pseudo random number generator. Watermark embedding is based on the block-based spread spectrum method and the strength of watermark is adjusted according to the local statistics of DCT coefficients in a zig-zag scan line in AC subband to achieve a good balance between imperceptibility and robustness. The proposed authentication technique can distinguish between malicious and innocuous manipulations by the use of content-based robust watermarking. Threshold selection for the verification of authentication is analyzed statistically. The numerical experiments show that the proposed technique is very efficient in the performance of robust authentication.

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