Erasable Authentication Watermarking in Binary Document Images

In this paper, we propose a new secure authentication method in binary document images using erasable watermarks. For localization, a sufficient number of low-distortion pixels may not be available in a block and to embed the authentication signature with blind detection constraint poses a challenging problem. Also, a perceptual watermark cannot be embedded in white or background regions of the document image, making such regions insecure against hostile attacks. In the proposed method, an erasable watermark is designed and embedded in each block of a document image for localization against tampering and Holliman-Memon attack. After verifying the content of each block, the exact copy of original image can be restored at the blind detector.