An efficient and blind audio watermarking technique in DCT domain

A blind audio watermarking algorithm in Discrete Cosine Transform domain using the relationship among the consecutive groups of samples is proposed in this work. Here, we divided the DCT represented audio signal into equal-sized non-overlapping segments which in turn divided into four non-overlapping consecutive frames. Here, an informative relation between the frames in a segment is maintained to indicate the successful embedding of a watermark i.e. in case of embedding ‘1’ in a segment, make the value of the ‘difference between the first two frames’ higher than the value of the ‘difference between the last two frames’ at a distance of threshold value and we do the opposite if the watermark bit is ‘0’. Embedding a single watermark bit in multiple segments makes the scheme robust. In this work, the size of frame and the segment entirely depend on the number of watermark bit which helps the proposed scheme to increase the capacity of watermarking. Additionally, in order to maintain security against hackers a secret key permutation is proposed to apply on the watermark message. The experimental result shows that the method provides high robustness against common signal manipulation as well as high capacity without significant perceptual distortion.