Copyright Protection of Plain Text Using Digital Watermarking

Abstract

With widespread use of Internet and other communication technologies, it has become extremely easy to reproduce, communicate, and distribute digital contents. As a result, authentication and copyright protection issues have arisen. Text is the most extensively used medium travelling over the Internet besides image, audio, and video. The major part of books, newspapers, web pages, advertisement, research papers, legal documents, letters, novels, poetry, and many other documents is simply the plain text. Copyright protection of plain text is a significant issue which cannot be condoned. The existing solution for watermarking of plain text documents are not robust towards random tampering attacks and are inapplicable for numerous domains. In this thesis, we have proposed a zero-watermarking approach towards text watermarking. We have provided a number of text watermarking solutions using inherent constituents of text such as double letters, prepositions, words, sentences, and text structure to protect text against digital forgery. We have designed a corpus having text of variable length and diversity; containing original as well as attacked samples with various volumes and forms of attacks. Instead of using binary watermarks on text, we used alphabetical, image, and hybrid watermarks. Experimental results illustrate the effectiveness of the proposed algorithms on text encountering combined insertion, deletion, and re-ordering attacks, both in the dispersed and localized forms. The results are also compared with the recent work on text watermarking.