The Research Of DCT-Domain Watermarking And Text Watermarking Algorithm

With the popularity of network communication, many traditional media is digitizing. The following side effect of transmitting digital media on network is that malicious individuals or groups may copy or disseminate copyrighted work without its owners' permission. So it has become an immediate practical problems that how to implement copyright protection and information security in network environment.On the basis of discussing digital watermarking theory and technology, the research work is as following:(1) A new adaptive digital robust watermarking algorithm is presented. The algorithm enhances the watermark robustness and anti-jamming capability by choosing DCT coefficients with JPEG matrix. It coordinates the contradiction of watermark's concealment and effect. Scrambling encryption technology reduces the relativity among watermarking data but hugely increases the security of watermarking. When making attacks on various images to test the algorithm's robustness, it shows that it has better robustness and effectiveness when compared to the wavelet algorithm and the conventional DCT algorithm.(2) When refer to the problems of weak anti-aggressive, poor robustness and transparency of digital watermarking in formatted Chinese text, after fully consideration of Chinese character's features, this paper proposes a new robust text digital watermarking algorithm based on the structure knowledge of Chinese characters. The research is quite important to the development and application of text information safety. Furthermore, it is also a beneficial try to improve the comparatively weak security mechanism on the Internet at present.(3) To solve the problem of illegally copying, pirating and propagating on network blogs, a double watermark copyright protecting algorithm is proposed based on natural language processing. The algorithm technically solves the copyright protection problem on blogs and it can also decide copyright infringement quite precisely. It can not only combine electronic signatures encryption technology but also ensure its integrity.