ABSTRACT

Authentication and copyright protection for digital contents over the Internet can be achieved through digital watermarking. The major components of the Internet are textual contents. Hence protection of plain text documents requires more attention. In this paper, we propose an invisible watermarking algorithm based on the occurrence of non-vowel ASCII characters that uses combined image and text watermark for protection of the text document. The watermark is logically embedded in the text and a watermark key is generated. Later the watermark is extracted to prove the identity. The experiments show that the new method is efficient as well as effective for protecting text documents.