Topology based fragile watermark for binary image

We propose a novel topology based data hiding scheme for binary image. Cutting the original image into equal blocks, and considering the topological structure for the chosen embeddable blocks with almost balanced number of white pixels and black pixels, we set a mapping between the embeddable blocks hiding before and after. We embed one bit via the odd-even enforcement in each embeddable block, and keep the invariant embeddable features in the mapping. The hidden data can be extracted without using the original image as a blind watermark scheme. We also provide another scheme with more hiding capacity by using the original image, keeping the same visual distortion level as the blind watermark scheme. Algorithms are given to construct the mapping relationships and some security issues are considered. Theoretical analysis and experimental results show that our scheme is very efficient in the hiding and extraction process, and has satisfied hiding capacity and visual quality.