Image Authentication Technology Based On Digital Watermarking

Digtial watermarking technique becomes a research hot-spot in recent years. It overcomes the shortcomings of encrpytion techniques in multimedia version protection and multimedia authentication, and provides the complementary solution for encrpytion techniques.Starting with the practical requirements, this paper gives an analysis on the current work of digital watermarking related to the multimedia authentication thery, and researches on the modern cryptography theory. This paper discusses the characteristics and restrictions for each method, and presents an watermarking algorithm based on these two theories, which includes:1. With the reference of digital signature theroy, presenting a practical authentication algorithm based on fragile watermarking.the algorithm has applied patent right.2. Designing a authentication algorithm based on self-embedded watermarking, for needs of electrionic authentication.3. Analyzing the character of the authentication algorithm in the compression field and designing a secure authentication algorithm in the JPEG compression field.Following work is to be creative:1. Presenting a new concept of authentication chain.2. Introducing a asymmetry key into authentication algorithm, especailly in the loss compression field algorithm, to enhance more security.3. Pointing out it's not practical to decide the authenticity of picture only by the comparison result of the relationship coefficient, which is between target watermarking and the one being detected, and the threshold. Presenting an improved method which demand the two to be identical.And, there are some other creative ideas recorded in the conclusion of some chapter for its relation to corresponding algorithm.Then, we can know that what mostly characterize the algorithms presented in this paper are security and practicality. It's also suggested that the research on multimedia data authentication should aim at concrete situation. It's undoubtedly that designing the watermark scheme based on watermark and cryptology should be promising.