Anti-collusion Attack Digital Fingerprint System

Digital fingerprint is a kind of pro-tools for the court to gather evidence and clues to track, before the distribution of content embedded in the same copy with only different marks, each digital fingerprint can be used to track who is a non-authorized use of these content clues. Collusion attack is a kind of combined attack, which is a group user having the same content with different fingerprints, aimed at undermining the hidden digital watermark. In the multimedia data, the design resistance of the anti-collusion fingerprinting system is facing many challenges. In this paper, a hybrid SVD-DCT anti-collusion fingerprinting algorithm to solve the ambiguity and high false alarm rates of the traditional SVD-based digital watermarking algorithm while testing the relevance, but they can not overcome the shortcomings of anti-collusion.Our SVD-based digital watermarking algorithm to do the following improvements: a) because of the importance of singular vectors, we will be embedded into the DC coefficient is more robust than in the AC coefficient; another reason is that the singular vectors of SVD is the standardization of orthogonal vectors, the extent of which is between -1 and 1. So DC coefficient of the impact is not great, would not undermine the perceived quality of the original image, while the larger singular value range, it is likely to exceed perception gap and undermine the perceived quality of the original image; b) make full use of the original signal perceptible information, Watson perceptual model will be used for the overall watermark embedding strength of the zoom control; c) and use of Watson's perceptual model for watermark embedding partial zoom. Based on the above we have proposed a hybrid SVD-DCT digital watermarking based shape perception algorithm.At the same time, in order to further enhance the watermarking algorithm's ability to resist collusion attack, we propose the idea of basis watermark as control parameters, which with the singular values at the same time embed in the cover image. We first use of digital fingerprint for SVD, singular value embedded in the sub-block transformed DCT coefficient matrix of cover image, the difference with the traditional digital watermarking algorithm based on SVD is that we will embed based fingerprint as control parameters in the DC component of the sub-block DCT transform matrix after. In detection, extract the control parameters for monitoring the similarity first, if it meets a certain threshold, and then to check the relevance of the entire fingerprint. This sub-block strategy embedded fingerprint compared to the traditional at the same time the whole embedded fingerprint methods, more energy can be embedded for fingerprints, and has good robustness and can not be perceived of watermarked image. What is more, improve the capacity of the collusion resistance. The experimental results show that it not only improves the robustness of the watermark and can not be perceived of watermarked image, and can be resistance to the average collusion attack.