The Detection And Recovery Of The Audio Signal Tampering Based On Digital Watermark

The audio signals are sometimes tampered maliciously via communicating,to solve this condition,the fragile watermark self-recovery technique is used to protect the audio signals.In the traditional fragile watermark self-recovery framework,the reference information is generated by compressed original audio signal.The reference information and check information are embedded into the least significant bit layers of the original signal;the generated signal is called the watermarked signal.At the receiver end,the check information is used to detect the tampered area;the reference information is used to content recovery.The entire recovery procedure does not need any other information,expect for the received signal and the shared secret key;so the recovery procedure is self-recovery.Moreover,the embedded watermark is invisible and fragile.This dissertation proposes fragile watermark self-recovery algorithm at the condition of various the least significant bit layers;the proposed algorithm is based on the traditional one.The proposed method deduces the best choices of other parameters when the least significant bit layers change;the exclusive method is used in this work.Moreover,the experimental results confirms that the relationship between the least significant bit layers and the invisibility of the watermark and the intelligence of the recovered signal.When the number of the least significant bit layers is increasing,the invisibility of the watermark is worse;the intelligence of the recovered signal is improved firstly and then declined;the peak value is achieved at six.Moreover,the experimental results show that the three to six the least significant bit layers are recommended in the real application conditions.The research explores the applied range of the fragile watermark self-recovery technique.This dissertation introduces the fragile watermark self-recovery technique which based on the discrete cosine transform and compressed sensing.The framework fully uses the sparsity of the transformed signal and the sparse reconstruction;the framework can recover the tampered signal with high quality when the tampered rate is high.Moreover,the various layers of the framework is also proposed in the dissertation.Moreover,the dissertation firstly proposed the fragile watermark self-recovery framework based on the fountain codes;the fountain codes and digital watermark are combined perfectly to design the algorithm.The related parameters are also deduced;the algorithm can recover the tampered signal perfectly in theory.