NDFT-based audio watermarking scheme with high robustness against malicious attack

Due to public frequency points leading to weak robustness against malicious attack in DFT-based audio watermarking algorithm, a novel audio watermarking scheme based on nonuniform discrete Fourier transform (NDFT) is proposed to improve robustness against malicious attack in this paper. NDFT transform could set up random sampling points in frequency domain as desired rather than fixed frequency points in DFT. The characteristic of NDFT provides the possibility to hide embedding positions. In the NDFT-domain selectable frequency range which satisfies necessary requirements of audio watermarking scheme, the proposed scheme utilizes chaotic system to select embedding points for random and hidden embedding positions. Theoretical analysis and simulation results show that the proposed scheme not only guarantees robustness against common operations, but also further improves systemic security and robustness against malicious attack due to the secret embedding position.