The Research Of Digital Watermark Based On Databases

It is the information age.now. With the rapid development and wide application of the database and Internet, it is easy to get digital productions on internet. The security problem of database absorbs more and more researchers'attention. How to protect the copyright of database has been one of the issues in the field of database security. For a long time, to make the unauthorized information be not able to transmit is the encryption technique. But the encrypted information isn't easy to transmit, and if the encrypted information is decrypted by someone, it will be not protected by the encryption technique. Now, the digital watermarking technique is an effective method to protect the copyright of digital productions. It is a hot topic now.Based on the analysis of existing digital watermarking algorithms of database, several techniques are discussed in this paper. And some new techniques are brought forward by the author of this paper, Most of them are proved that they are effective by the experimental data.In the first chapter of this paper, The background, purpose, significance, situation, model, basic theory of the digital watermark based on database are described, and the difficulties and key points of the digital watermark based on database are explained too. How to attack the digital watermark based on database is explained in detail. In the second chapter and the third chapter of this paper, some techniques are discussed by embedding process. A scrambling algorithm based on Hash fuction is put forward in the second chapter, it has some advantages over two frequently-used scrambling algorithms. A new secret sharing scheme is put forward in the first section of the third chapter, which is an improvement algorithm based on an old algorithm. To improve the robustness of the digital watermark based on database by using combining information is an issue, which is analyzed in the second section. The dynamic weight encode model is designed in the third section. Several embedding models of the digital watermark based on database are analyzed and compared in the fourth section, two embedding models of the digital watermark based on database is tested by experiments.In the last part of this paper, the data of experimentations is analyzed, and a new rule is used to evaluate the robustness of digital watermark. The future of the digital watermark based on database is analyzed.Most of the algorithms which are designed in this paper are feasible, and some of the algorithms which are designed in this paper can be used to improve the robustness of digital watermark.