Research On Audio Information Hiding Technology Based On Spread Spectrum

Audio information hiding technology is an important branch in the field of information hiding technology. It is broadly used on digital watermarking and covert communication. The information hiding algorithm based on spread spectrum has many advantages, for example, strong ability of anti-jamming, hiding and safety. Because of this, it becomes a focus for researchers since it is proposed. This dissertation mainly researches the audio information hiding technology based on spread spectrum. The main contribution is as follows:Research on the interaction relationship of related results between the carrier signal, embedding strength and spreading sequences based on statistical theory. This is used to choose from guiding the spreading sequence length and related detection threshold.This dissertation proposes a point by point independent calculating method for masking threshold in frequency domain, after considering the effect of simultaneous masking and post-masking. This method will use auditory masking to increase the hiding capacity and robustness in the context of keeping the perceptual transparency of the synthesized audio.This dissertation proposes an improving audio information hiding algorithm by in-phase modifying and multi-frame overlay. This algorithm is not sensitive to desynchronization, and the watermarked audio signal has good robustness against many attacks such as noise, filtering.This dissertation proposes an information hiding algorithm based on sinusoidal modulation. This algorithm modulates the hiding information by harmonic related sinusoidal signal and embeds it into the original audio spectrum. The embedded information can be detected by FFT algorithm and the calculating efficiency is high. There are many harmonic waves to choose from and every harmonic wave represents a different coding mode, so the hiding capacity is huge. Besides, the algorithm uses perceptual reshaping when embedded and this ensures the perceptual transparency of the synthesized audio.The proposed algorithms in this thesis are applied in different audio carrier in the simulation experiments. Theoretical analysis and simulation results show that the proposed algorithms are not sensitive to the loss of synchronization, and can be effective against noise, filtering and other attacks. The proposed algorithms are robust and reliable.