Study On Digital Watermark Technologies Based On Chaotic Encryption And Adaptive Watermarking Algorithm

With the development of computer technology and network, digital media can be spread and copied easily. At the same time, digital copyright protection has become a serious problem. Watermarking technology, which is nowadays developing fast in the field of information security, is considered as a new means to solve this problem. It is protect the integrity and the ownership for the digital media products against piracy and attacks, by embedding the particular important information into host media.In this article, the current conditions of developing digital watermark technologies are studied. The principle and main implementations of digital watermarking technologies are first introduced. Their corresponding watermark detecting and evaluating methods are then developed. Some application area of digital watermark technology is also discussed.An adaptive watermarking algorithm based on DCT field is proposed in this article. In this algorithm, the watermark image is first scrambled with HASH function, and then the image information is encrypted based on chaos. Thus the security of the watermark is enhanced. In the processing of embedding watermark, the human visual sensitivity to space-frequency is deeply studied, and the human visual characteristic is applied to adaptively adjust the coefficients of DCT block. The experimental results demonstrate this algorithm is of much better security and robustness against the traditional attacks including cropping, mean filter, random noise. In addition, a blind extracting algorithm is also introduced in this article.Finally the researching trend of this technology is discussed and conclusion of this article is drawn at the end.