Research On Audio Information Hiding Algorithm Based On Vector Quantization Technology

The digitization of information has produced enormous and revolutionary impaction both on our society and on our daily life. The rapid development of the digital multimedia technology and the widespread popularity of the Internet have brought about convenience to our life, opportunity to our career, but at the same time, many challenging questions to us. Such questions include how to achieve effective intellectual protection to the digital multimedia arts and how to accomplish secure secret communication, etc. Due to the various shortcomings and application constraints of conventional cryptography method, information hiding, as a new technology and method in information security domain, has drawn more and more attention from both research communities and application groups. Information hiding technology includes digital watermarking and steganography, applied to the copyright protection of the digital multimedia arts and the covert communication for the secret message.At first, the Vector Quantization (VQ) technology was coming up as a more valid data compression method. VQ has been applied to static and dynamic image coding, speech and audio coding, speech recognition and so on. Moreover, with the thorough study of VQ and the crossover of multiple disciplines, the application area of VQ has been becoming wider. Examples can be found in information hiding, image retrieval, database compression and image restore, etc. The existing research on VQ-based information hiding technique is fasten on using static image or video as the carrier signals, and there are rare reports on the combination of VQ and audio (or speech) information hiding. This dissertation makes a beneficial attempt in this direction, and the main works focusing on the combination of VQ and audio (or speech) information hiding technology are listed as follows:(1) A robust audio digital watermarking algorithm based on VQ and Modified Discrete Cosine Transform (DCT) is presented, and then the improvement, focusing on the audio quality, is made by using the Discrete Wavelet Transform (DWT). Furthermore, the synchronization of embedded watermark is fulfilled by embedding the self-synchronization code. (2) A multipurpose audio digital watermarking algorithm based on VQ and DCT for digital copyright protection and tampering authentication is presented. Experiments are carried to verify its effectiveness.(3) A speech information hiding algorithm based on VQ technology and low bit-rate speech codec is proposed. And a covert communication system based on this algorithm via Public Switching Telephone Network (PSTN) is implemented to justify the algorithm's validation.(4) An audio fingerprinting algorithm based on Discret Wavelet Transform (DWT) is proposed. This algorithm designed an audio fingerprinting method according to the relationship of the variance of every wavelet components. The algorithm is robust to the common content preserving attacks and the addition of Gaussian White Noise, especially to the Linear Speed Change attack, while remains high identification rate.Finally, the research achievements on audio and speech information hiding technique based on vector quantization are summarized, and some new highlights in this research direction which need to be further explored are pointed out.