Digital watermarking algorithm based on discrete Fourier transform

A digital watermarking algorithm based on double encryption and discrete Fourier transform(DFT) was proposed.To ensure security,the chaotic scrambling based on logical mapping is conducted before embedding carrier image,then the implementation of encryption by Arnold transform is furthered.Then according to the bit values of watermarking,it is to be embedded to modify the phase of DFT coefficients.Experimental results show that the algorithm has good invisibility and robustness.