A Disquisition Of Digital Photograph's Authentication Technique Based On Digital Watermark

With the rapid growth of the network technology and the multimedia technology, the security of the digital information faces serious challenges. It has become a very important task to authenticate the authenticity and integrality of the multimedia information effectively and to protect the copyright o the multimedia information. As a good approach of protecting the copyright and authenticating the multimedia information, digital watermarking has been a hot topic in the information security field.Digital photograph's authenticity get oppugned because of it can be dealed with variously by computer software .In this paper, digital watermark technique based on wavelet transform is used for the sake of authenticating the authentication of digital photograph . According to the operation principle of the digital camera, a arithmetic is be proposed by which digital watermark is embed automatically when the digital camera is getting shots. Digital watermarking is extracted when the photograph is being authenticated.In this thesis, some basic concepts in digital watermarking are introduced. First, including the basic theory, characteristics, categories, typical algorithm of the digital watermarking, application areas, all kinds of attacking means of the digital watermarking and the applications in the fields of the authentication of the image.Then, the algorithm of digital watermark technology has been analysed in the round. Further research has been made in watermark embedding model of embedding and inspection, the dual-watermark method aimed at interpretation attack, the fragile method facing image content authentication, and so on. Then, this scheme exploits the chaotic features such as sensitivity to the initial condition to scrambling watermarking before imbedding it into host image. As a result, if the key is unknown, the watermarking can't be rebuilded despite the algorithem is public and the watermarking is detected. So the watermarking system can obtain good security and resistance to attack. Meanwhile, based on the technology of the wavelet transform and the visual mask character of people, a semi-fragile watermarking algorithm used in the content authentication of the digital images was proposed and simulated.Finally, the watermarking algorithm was applied in digital camera, According to the operation principle of the digital camera, a arithmetic is be proposed by which digital watermark is embed automatically when the digital camera is getting shots. The result of research point out: the photograph not only can be authenticated availably by observing change of the digital watermarking, but also can point out the position of the photograph where is juggled accurately.