The Digital Fingerprinting System Based On Image

While the rapid development of network and digital technology has brought convenience to people's lives, it has also brought conflict. The copyright protection has been serious impacted due to the easy modification, replication and redistribution of creative works in digital form. Digital fingerprinting has been put forward as an effective means for copyright protection and attracts the concern of scholars home and abroad. In digital fingerprinting, a unique customer identification called fingerprinting is embedded in each distributed copy related to user, So that when an illegal copy is found, it's possible to trace and identify the source of illicit copy by extracting the fingerprinting from the illegal copy.This article focuses on the research of the digital fingerprinting technology. Firstly, it introduces the basic model, requirements and some attack measures of digital fingerprinting system, summarizes the several classic digital fingerprinting scheme during the development of digital fingerprinting by analyzing the limitation of them.Secondly, in order to solve the low efficiency in construction and tracking of traditional digital fingerprinting, a new fingerprinting scheme based on the FDM(Frequency Division Multiplexing) technique is proposed in this article. In this scheme, the fingerprinting, which is a random sample from Cosine signal with no spectral overlap, is embedded in the middle-frequency coefficients of the original image through the spreading sequences. In that way, the algorithm becomes simpler, publishers only need to save the Cosine signal frequency rather than the whole fingerprinting sequence so that a lot of extra memory space could be reduced. What's more, by taking FFT(Fast Fourier Transform) as a tracking algorithm and identifying the illicit copies through spectrum amplitudes, the complexity of tracking is reduced. Meanwhile, the new scheme is further improved by combining the technology of OFDM(Orthogonal Frequency Division Multiplexing) so as to decrease the code length of fingerpringting. The feasibility and efficiency of the scheme is demonstrated by experiment which simulates some kinds of collusion attacking.Finally, this paper raises a measure which combining the digital fingerprinting and encryption in order to solve the problem of encryption technology, which is not able to protect decrypted images. The analysis of three safety combining models is made primarily by introducing the advantages and disadvantages of each of them. In the third model, the images are encytpted by applying chaotic sequence in send ports,different decryption sequences are produced according to different fingerprinting of users in receive ports, the fingerprinting is embedded into images when these images are decrypted. The security and the anti-collusion of the measure is proved by a experiment at last.