The present paper proposes a multidimensional coupled chaotic map as a pseudo random number generator. Based on an introduced dynamical systems, a watermark scheme is presented. By modifying the original image and embedding a watermark in the difference values within the original image, the proposed scheme overcomes the problem of embedding a watermark in the spatial domain. As the watermark extraction does not require the original image, the introduced model can be employed for practical applications. This algorithm tries to improve the problem of failure of embedding in small key space, embedding speed and level of security. 
Design and implementation of coupled chaotic maps in watermarking