Text Watermarking Using Combined Image-plus-Text Watermark

Authentication and copyright protection of digital contents over the internet is an important issue. Digital watermarking provides a complete authentication and copyright protection solution for this problem. Besides, image, audio, and video; text is the most dominant medium travelling over the internet and it requires complete protection. Text watermarking techniques have been developed in past to protect the text from illegal copying, forgery, redistribution and to prevent copyright violations. In this paper, we propose a novel text watermarking algorithm using combined image-plus-text watermark to fully protect the text document. The watermark is logically embedded in the text and is extracted later to prove ownership. Experimental results demonstrate the effectiveness of proposed algorithm under localized as well as dispersed tampering attacks on the text.