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An Algorithm for Authentication of Digital Images

The rapid growth of digital multimedia technologies brings tremendous attention to the field of digital authentication. The owner or the distributor of the digital images can insert a unique watermark into copies for different customers or receivers, which will be helpful to identify the source of illegal copies. In digital watermarking, robustness is still a challenging problem if different sets of attacks need to be tolerated simultaneously. In this paper we present an original spatial authentication technique for digital images. Our approach modifies blocks of the image by insertion of a spatial watermark. A spatial mask of suitable size is used to hide data with less visual impairments. The watermark insertion process exploits average color of the homogeneity regions of the cover image. The complexity of the algorithms is proved to be O(n), where ‘n’ is the nodes number of virtual graph for watermark. The authentication method developed below works for all types of digital image.