Fast Fourier Transforms and Quadratic Forms for Digital Audio Watermarking

In this paper a new technique of encryption for embedding secret information in the frequency domains of a cover audio signal is described. A novel method is presented for inaudibly hiding information in an audio signal. The method uses quadratic form as key matrix. The data is first encrypted using the key matrix. The secure data is further embedded in the audio signal in frequency domain using fast Fourier transforms and the results have been analyzed. This consists of data encryption at two levels and the cipher text so obtained becomes quite impossible to break or to interrupt.