一种新的基于密钥的混沌数字水印方法

针对现有混沌水印的安全性差、易被破译的问题，提出一种基于密钥的混沌数字水印方法。该方法在现有的混沌数字水印系统基础上，增加一个混沌映射，并将其初值作为私有密钥来克服有限字长效应的影响和提高数字水印算法抵抗群举攻击的性能。嵌入水印时，将选择的图像分块DCT中频系数与混沌序列相加，进行取模运算后再嵌入混沌映射模型进行迭代。检测时，利用相应的混沌映射模型生成混沌水印序列，并进行相关检测。研究结果验证本文提出这种方法的安全性和有效性。

A new chaotic digital watermarking method based on private key

To overcome finite word length effects and improve its property of high resistant to repeated group attack, a new chaotic digital watermarking method based on private keys, where the initial value of a chaotic map as a private key is added to the existing chaotic watermarking systems, is proposed in this paper. The chaotic signal is embedded into the selected block middle-frequency DCT coefficients, by the same time taking a modular operation on the sum and embedding the result of the modular operation in the iteration of the chaotic generating systems. The chaotic sequence is retrieved from the watermarking image by using the corresponding chaotic model in the correlative detector. The simulation results show that the performance of this proposed watermarking system is better security performance than that of the single chaotic map watermarking systems.