Copyright Protection for Text Documents

Due to the rapid development in communication and multimedia technology, different techniques are used for copyright protection and monitoring illegal copying of these media. One of the most important techniques is digital watermarking.
In this research, an algorithm for copyright protection of text documents was designed and implemented.
The algorithm includes three steps: Watermark generation using the original text, watermark embedding using space embedding approach and finally watermark extracting and comparing it with the original one using normalized correlation.
Experimental results are presented to demonstrate the robustness of the algorithm against common attacks which alter the embedded text like changing some letters of the text, changing structure of text sentences, or changing the number of spaces between the words etc.
Matlab Ver. 6.5 was used to implement the algorithm under Windows.