Blind watermarking applied to image authentication

To prevent image manipulations and fraudulent use of modified images, the embedding of semi-fragile digital watermarks into image data has been proposed. The watermark should survive modifications introduced by random noise or compression, but should not be detectable from non-authentic regions of the image. The original image cannot be used by the watermark detector to verify the authenticity of the image. In this paper, we investigate the application of a recently developed quantization based watermarking scheme to image authentication. The watermarking technology, called Scalar Costa Scheme (SCS), allows reliable blind watermark detection from a small number of pixels, and thus enables the detection of local modifications to the image content.