Digital Audio Watermarking Algorithm

With the rapid development of the computer network and multimedia information processing technique in recent years,digital image,audio, graphics,flash and text have become more popular and more useful. It increases the efficiency of the information broadcasting and predigests the exchange and transmission of the information more which brings a lot of convience for our life. Meanwhile,it also brings some side effect. For example,digital works may be copied,tampered and broadcasted without the permission of the author of the digital works. Therefore,how to carry out copyright protection and ensure the security of the information has become on of the urgent problems to be solved in digital communication.This paper describes the concept,framework,the classification,main attacks , some benchmarks and application of audio watermarking techniques,finally introduces Human Auditory System and several kinds of existent audio watermarking algorithms.This paper presents audio zero-watermarking scheme based on discrete cosine transform with good robustness. Compared with the traditional audio watermarking schemes,the proposed scheme can solve the contradiction among robustness,imperceptibility and bandwidth perfectly. The proposed scheme is based on the steady positive-negative sign of the DC coefficients in DCT domain. In the embedding scheme,the original audio is first divided into several segments and the DC coefficients are extracted from DCT domain of each segment. Then,a key,which is used for watermark detection,is generated with the character of the DC coefficients with higher absolute value and the watermark sequence. Compared with [64], the simulation result shows that the proposed scheme has wide bandwidth and perfect imperceptibility,as well as better robustness.Another scheme this paper presents is a novel fragile speech watermarking scheme for Tamper Discrimination. Compared with the traditional fragile speech watermarking schemes,the proposed scheme can not only be used for content authentication,tamper localization and original speech signal reconstruction,but also for Tamper Discrimination. That is,it can distinguish whether the watermark,the speech or both of them are tampered. One important application of this scheme is testimony record protection. It can effectively authenticate the integrity of the testimony record and ensure the authenticity of the record content even if it is tampered in the above 3 ways. In order to recover the original speech signal more accurately,A-law algorithm is applied for the quantization of the DWT low-frequency sub-band coefficients of the original speech signal. Using these quantization coefficients,the watermark signal is generated. Finally,the scrambled watermark bits are embedded into the LSBs (Least Significant Bits) of the randomly selected coefficients of the original speech signal. Simulation results show the good performance of the proposed scheme on tamper localization,original speech signal reconstruction and tamper discrimination , which demonstrates the feasibility of the scheme.