Efficient audio data hiding via parallel combinatory spread spectrum

Spread spectrum (SS) modulation is one of the most commonly used methods for data hiding. However, the capacity of SS-based methods is rather limited. To improve the hiding efficiency, this paper presents a method that employs the parallel combinatory spread spectrum (PCSS), in which the hidden data can be transmitted in parallel with a combination of a few pseudo noise sequences. An informed embedding strategy is applied to PCSS data hiding to improve its robustness. Compared with the methods using the techniques of code division multiple access (CDMA) and M-ary SS modulation, the proposed method can provide a much higher achievable capacity with similar decoding complexity. This method is evaluated in an audio data hiding system, and the experimental results show that the embedded data can resist typical signal processing and attacks, even in high-capacity applications.