An efficient and robust zero-watermarking scheme for audio based on DWT and DCT

A zero-watermarking scheme for audio based on the steady sign of certain DWT-DCT coefficients with maximal absolute value, is proposed. Compared with traditional watermarking schemes, the proposed scheme can solve the contradiction between robustness and imperceptibility perfectly without introducing audio quality degradation as occurred usually in traditional watermarking schemes. The multiresolution characteristic of discrete wavelet transform (DWT), the energy compression characteristic of discrete cosine transform (DCT) and the steady sign of certain DWT-DCT coefficients are combined to extract important features from the host audio signal, which are used to construct the secret key with the watermark image. Simulation results show that the proposed scheme has stronger robustness as well as security, as compared to the schemes in [5] and [8].