Audio information hiding based on distance metric

Spread spectrum techniques were invented in the 1950´s as a means of improving the security and reality of digital communications systems, and they are regularly employed in wireless systems today. A narrowband data signal, such as a frequency shift keying (FSK) signal for example, is converted into a spread signal by modulating it with a wideband spreading signal that is independent of the data signal. This process caused the spread signal to occupy a spectral bandwidth far in excess of the bandwidth of the original data signal. The data signal at the decoder is recovered by correlating the spread signal with a synchronized copy of the spreading signal, also known as dispreading. The spread-spectrum techniques for watermarking are very popular nowadays. Two commonly spread spectrum techniques are used direct sequence spread spectrum (DSSS) and frequency hopped spread spectrum (FHSS). In this paper, we concentrate on the DSSS technique in steganography.