A New Chinese Text Digital Watermarking for Copyright Protecting Word Document

More and more entriprises, organsizaions and goverments have used and distrubed information in word documents, pdf etc.. It makes easily to unauthorized copying and dissemination. According to DRM´s requirements, we evaluated several text watermarking methods for instructing practical applications, and proposed a new approach in text watermarking where inter-character spaces are slightly modified for coding and using background texture for introducing noise against OCR attack. The capacity is improved to 1/3 bit/character and robust to screen capture. It is efficient extracting watermarking from document or screen-capture-image. Our experiments suggest it is suitable for word documents and Chinese language.