Design and implementation of coupled chaotic maps in watermarking

We propose a multidimensional coupled chaotic map as a pseudo random number generator. Based on the introduced dynamical systems, a robust watermark scheme for copyright protection is proposed. By modifying the original image in transform domain and embedding a watermark in the difference values between the original image, the proposed scheme overcomes the weak robustness problem of embedding a watermark in the spatial domain. Besides, the watermark extraction does not require the original image so, it is more practical in real applications. This algorithm tries to improve the problem of failure of encryption in small key space, encryption speed and level of security.