Abstract
In this paper, the non-uniform discrete Fourier transform (NDFT) is utilized to randomly select sampling points in frequency domain, which could make the embedding points private. Furthermore, to improve security two different chaotic maps is used. One chaotic map is used to choose the NDFT domain embedding points for making them unpredictable; the other is used to encrypt the watermark to be embedding with purpose of resisting copy attacks. Theoretical analysis and simulation results show obviously that the proposed scheme has higher fidelity and superior security.