A content-based fragile watermarking scheme for image authentication

In this paper, we present an effective image authentication scheme that can tolerate incidental distortions but that indicates tampered regions in cases of malicious manipulation. After having divided an image into blocks in the spatial domain and having obtained the average of each block's pixel values, we represent the size relationship among three random blocks in a binary tree and use it as a fragile watermark. We insert the watermark, which has been extracted based on content, into the DCT block, which is the frequency domain of the image. The experimental results show that this is an effective technique of image authentication.