Speech Information Hiding Algorithm Based on Complete Binary Tree Dynamic Codebook Grouping

In order to protect the data security and privacy of Voice over Internet Protocol (VoIP), a new algorithm for speech information hiding is proposed based on complete binary tree dynamic codebook grouping (CBTDCG). The algorithm uses the quantization index modulation (QIM) method to divide the dynamic codebook into two parts (corresponding to the embedded secret information bits `0' and `1' respectively), and adopts the complete binary tree to achieve the optimal grouping. The utility of complete binary tree makes the algorithm have the characteristics of fast search and high accuracy. The sender selects the corresponding code word according to the secret information bits for embedding the secret information into carrier speech. At the receiving end, the secret information bits are extracted according to the features of the code word vectors by the receiver. The experimental results show that the hidden capacity of the algorithm is larger than 450bps and the loss of the PESQ is less than 4%. Verification shows that the algorithm possesses a good robustness with a low bit error rate after being interfered by noise and the speech stream carrying secret information has better imperceptibility.