The Research Of Text Digital Watermarking Technology Applied To The Digital Copyright Protection

The Internet technology is developing rapidly, which greatly promotes the development of network publishing industry. More and more electronic products are traded and propagated online, and piracy and illegal propagation phenomenon is more and more serious, Digital copyright protection problems become a bottleneck of the network publishing industry development. And the digital watermarking technology provides a new thought to solve the digital copyright protection problem. At present, most of the electronic documents published in network are PDF documents, therefore, the study of digital watermarking technology according to PDF documents will have an important application value in the field of digital copyright protection.According to the shortages of some existing watermark embedding algorithms, through analysis the structure of PDF documents and its related digital watermarking algorithm, this paper proposed two kinds of digital watermarking algorithm, one is based on PDF document structure and the other is based on PDF document ID. As to the digital watermarking algorithm based on PDF document structure, considering the characteristics that end-of-line marker cannot be showed in the document, this algorithm manages to embed watermark through replacing end-of-line markers of the cross-reference table with a fixed format. And the watermarking algorithm based on PDF document ID manages to embed watermark through replacing the first group string of ID. Due to the PDF document ID is sole and invariant, the embedded watermark is not easy to be removed, thus its robustness is good. The experimental results show that, the proposed algorithms can not only reach the standard of watermark capacity required by digital copyright protection, but have good concealment and practical applicability as well.Based on the above algorithm research achievements, this paper designs and implements a text watermarking system, which can embed the copyright information to the electronic document, meanwhile extract the copyright information from it. And the performance of the system is. tested and analyzed. This system has a broad application prospect and practical value in the network publishing industry.