一种心理声学模型的自同步音频水印方案

提出了一种鲁棒的数字音频水印方案,该方案主要特点：（1）应用双重置乱机制,保证水印的安全性;（2）利用心理声学模型算法,确定水印嵌入强度;（3）应用同步机制,实现水印的自同步检测;（4）在离散小波变换（DWT）域嵌入水印,提高水印的抗攻击能力;（5）利用高效的嵌入算法,提高水印的检测效率。仿真实验表明,该方案不但具有良好的不可感知性,还对诸如重采样、重量化、叠加噪声、低通滤波、MP3压缩等攻击具有较好的鲁棒性。     

基于Blakley方案的音频水印分存算法

提出了一种基于Blakley密钥共享方案的音频水印分存算法。算法将密钥分存的思想引入到音频水印算法中,将水印分存到音频数据的不同段中,检测时只需提取出部分水印信息就可以恢复出原始水印。算法同时采用了Bark码来解决剪切攻击带来的同步问题,并利用逼近信号统计特征和纠错码技术来提高算法的鲁棒性。实验证明,算法具有较强的抗剪切攻击能力。     

基于经验模式分解的音频水印算法

针对传统基于经验模式分解(EMD)的音频水印算法鲁棒性不强的问题,提出一种基于固有模态函数(IMF)极值的盲音频水印算法.首先对音频信号进行分帧,每个音频帧经过EMD后得到IMF; 接着利用均匀量化的方法将水印信息和同步码嵌入到最后一个IMF的极值中.所提算法的数据嵌入率是46.9~50.3 b/s,且携水印音频保持了原始音频的感知质量.对携水印音频进行加噪、MP3压缩、重新采样、滤波、剪切和重采样攻击后,提取出的水印信息变化不大,算法鲁棒性较好.与时间域和小波域算法相比,提出的算法在保证高数据嵌入率的同时,可以抵抗32 kb/s的MP3压缩攻击.     

基于DWT和均值量化的音频水印算法

提出基于小波包的离散小波变换和均值量化的音频水印算法。该算法的主要特点是：1）将音频信号根据嵌入的水印图像大小自适应地分段。利用Arnold变换对水印图像进行预处理,消除水印图像的相关性,提高图像的抗攻击性。2）采用小波包的离散小波变换,增加嵌入和提取效率,提高水印的透明性。3）水印信息嵌入到均值中,有较好的不可感知性。仿真实验表明：嵌入水印后音频的不可感知性较高,能够有效地抗击有损压缩、低通滤波和剪切等攻击。     

改进的动态图水印技术编码方案*

针对动态图水印性能评测指标之间相互制约的关系,寻找指标之间的平衡点,满足理想水印图的特征条件,结合现有的动态图水印技术编码方案,改进了一种编码方案。该改进方案利用二维PPCT编码纠错能力强、抗攻击性能好的特点以及K基数链表编码率高的优点,引入混合编码的思想,添加指针域,构造多个水印图,对真实水印起到混淆的作用。理论分析和实验结果表明,该改进方案提高了数据率、抗攻击能力和鲁棒性,是一种不错的水印编码方案。     

Audio watermarking scheme robust against desynchronization attacks based on kernel clustering

In this paper, we propose an adaptive audio watermarking scheme based on kernel fuzzy c-means (KFCM) clustering algorithm, which possesses robust ability against common signal processing and desynchronization attacks. The original audio signal is partitioned into audio frames and then each audio frame is further divided as two sub-frames. In order to resist desynchronization attacks, we embed a synchronization code into first sub-frame of each audio frame by using a mean quantization technique in temporal domain. Moreover, watermark signal is hid into DWT coefficients of second sub-frame of each audio frame by using an energy quantization technique. A local audio feature data set extracted from all audio frames is used to train a KFCM. The well-trained KFCM is used to adaptively control quantization steps in above two quantization techniques. The experimental results show the proposed scheme is robust to common signal processing (such as MP3 lossy compression, noise addition, filtering, re-sampling, re-quantizing) and desynchronization attacks (random cropping, pitch shifting, amplitude variation, time-scale modification, jittering).     

Audio watermarking scheme based on embedding strategy in low frequency components with a binary image

With the recent development of information technology and computer network, digital format of data has become more and more popular. However, a major problem faced by digital data providers and owners is protecting data from unauthorized copying and distribution. As a solution to the problem, digital watermark technology is now attracting attention as new method of protection against said unauthorized copying and distribution. The aim of the digital audio watermarking is to take prespecified data that carries certain information and hide it within the audio stream such that it is not audible to the human ear (i.e., transparent) but at the same time renders the file more resistant to removal (i.e., robust). In this paper, we propose a new method for embedding digital watermarks into audio signals in low frequency components, which method mitigates these and other related shortcomings. The proposed method uses the wavelet transform constructed by lifting-based wavelet transform (LBWT) in order to provide a fast implementation between watermark embedding and extraction parts. In the first stage of the proposed method, the original audio host signal is converted to a wavelet domain using LBWT. The signal is thus decomposed into low and high frequency components. Approximation coefficients correspond to low frequency components of the signal. Next, the watermark generated by pseudorandom numbers is embedded into wavelet approximation coefficients of the segmented host audio signal depending on the binary value of the binary image. The reason for embedding the watermark in the low frequency components is that these components' energy is greater than that of high frequency components in such a way that the watermark is inaudible; therefore, it should not alter the audible content and should not be easy to remove. The proposed method uses a binary image to decide whether or not the watermark generated by pseudorandom numbers is embedded in the audio host signal. To evaluate the performance of the proposed audio watermarking method, subjective and objective quality tests including bit error rate (BER) and signal-to-noise ratio (SNR) are conducted. The tests' results show that the proposed method yields a high recovery rate after attacks by commonly used audio data manipulations such as low-pass filtering, requantization, resampling and MP3 compression.     

基于Shamir秘密共享方案和零水印的音频水印算法

提出一种基于Shamir秘密共享方案和零水印技术的数字水印算法。该算法首先将音频信号分成n段,并根据Shamir秘密共享方案将水印信息分成n份,然后对n段音频信号进行离散小波分解,将水印信息分存到相应的n段音频信号的低频系数中,然后对低频系数运用零水印技术构造鲁棒水印。实验表明,该算法中的零水印对滤波、有损压缩等常见水印攻击方式有较强的鲁棒性,能达到音频作品版权保护的目的,同时分存的水印信息不仅对音频信号的整体攻击具有较强的敏感性,可以达到内容认证的目的,而且能够抵抗剪切以及对音频文件局部的攻击,并确定被攻击的位置。     

A dynamic watermarking scheme for quantum images using quantum wavelet transform

In this paper, a novel watermarking scheme based on quantum wavelet transform (QWT) is proposed. Firstly, the wavelet coefficients are extracted by executing QWT on quantum image. Then, we utilize a dynamic vector for controlling embedding strength instead of a fixed parameter for embedding process in other schemes. Analysis and results show that the proposed dynamic watermarking scheme has better visual quality under a higher embedding capacity and outperforms the existing schemes in the literature.     

VQ-based watermarking scheme with genetic codebook partition

To enhance the traditional vector quantisation (VQ) system by adding the watermarking ability, a digital image watermarking scheme, which modifies the VQ indices to carry watermark bits, is presented. This scheme partitions the main codebook into two sub-codebooks by referring to the user-key. Then, for each input vector of the cover image, a sub-codebook is selected according to the watermark bit to be embedding. The traditional VQ coding procedure is then done using the sub-codebook for the vector. Furthermore, to improve the performance of the scheme, a genetic codebook partition (GCP) procedure, which employs the genetic algorithm (GA) to find a better way to split the codebook, is proposed. It is demonstrated that the proposed methods provide faster encoding time, better imperceptibility, stronger robustness under some common attacks, and easier implementation than some related VQ-based watermarking schemes proposed in the literature.     

云计算环境约束下的软件水印方案

针对云计算环境下的软件知识产权保护需求,提出一种基于非等价语义混淆理论的软件水印方案。方案设计了一种非等价语义混淆方法,用于切割、隐藏代码语义,同时利用混淆规则虚拟映射水印。切割后的语义放置在一个独立的模块中,验证水印信息、恢复程序正常执行。对该方案的反编译实验表明,其逆向工程难度大,保障了水印顽健性,可有效保护放置在云端的代码。     

新的分形水印方案的研究

以基于矩的图像归一化技术及分形相关知识为基础,提出一种可有效抵抗几何攻击的数字水印新方案。方案利用归一化技术将原始图像映射到几何不变空间内,结合不变质心理论提取出归一化图像的重要区域;利用分形,通过调整DCT中频系数,将水印自适应地嵌入到重要区域的自相似块中。仿真实验结果表明,方案不仅具有较好的透明性,而且对常规信号处理和几何攻击均具有较好的鲁棒性。     

基于混沌理论的音频数字水印算法研究

音频信息隐藏技术已成为近年来的研究热点之一,将混沌理论引入到音频水印系统的研究中,设计了一种将一段音频作为水印,利用混沌序列选择部分原始音频信号作为载体,将混沌加密后的音频水印嵌入到载体的小波系数中的音频信息隐藏方法。实验表明,水印具有很强的安全性和鲁棒性。     

面向公共信息传播的音频水印算法

提出了一种基于小波分解和倒谱技术的音频数字水印算法,该算法通过对原始音频进行小波多级分解,从中选取低频系数进行倒谱变换。通过统计均值的计算和调整方法设计,完成了水印的嵌入。实验结果表明该算法能够有效地抵抗A/D和D/A攻击,误码率为0,隐藏容量较大。同时,本算法还能够抵抗一定的AMR攻击,为手机音频的安全传播和管理提供了新的前景。     

A motion location based video watermarking scheme using ICA to extract dynamic frames

In this paper, we propose a novel video watermarking scheme based on motion location. In the proposed scheme, independent component analysis is used to extract a dynamic frame from two successive frames of original video, and the motion is located by using the variance of 8 × 8 block in the extracted dynamic frame. Then according to the located motion, we choose a corresponding region in the former frame of the two successive frames, where watermark is embedded by using the quantization index modulation algorithm. The procedure above is repeated until each frame of the video (excluding the last one) is watermarked. The simulations show that the proposed scheme has a good performance to resist Gaussian noising, MPEG2 compression, frame dropping, frame cropping, etc. This work was originally presented in the Fifth International Symposium on Neural Networks.     

An efficient fragile watermarking scheme with multilevel tamper detection and recovery based on dynamic domain selection

Self-recoverable fragile watermarking is meant for accurate tamper localization as well as image recovery with superior visual quality. However, most of the existing state of art approaches perform authentication and recovery on block basis owing to which the entire block is categorized as tampered in case of alteration of one or more pixels of it. This, results in staircase formation of tamper detected regions, hence lacking in accuracy. Furthermore, the visual quality of the recovered image also deteriorates as an approximate value is assigned to all the block pixels corresponding to the altered region. The proposed watermarking scheme performs both authentication and recovery pixelwise. The authentication of each pixel is done via multi level tamper detection(MLTD) through three authentication bits based on value, location and neighbourhood information. The domain for image recovery is chosen dynamically based on the content of the block, may it be in spatial domain for smooth blocks or frequency domain for the rough ones. This provides high accuracy in recovery. As the embedding of recovery information is done in the frequency domain, the imperceptibility of the watermarked image scheme remains high. Also, embedding of authentication information in the spatial domain maintains its fragile nature. Even for higher tampering ratios, the lost content is rebuilt with high peak signal to noise ratio(PSNR) of the recovered image. The probabilities of false rejection and false acceptance head towards the ideal value for most of the empirical analysis. Comparative study via metric evaluation of probability of false rejection (PFR), probability of false acceptance (PFA) and PSNR of recovered image for different standard test cover images demonstrate the efficacy of the proposed scheme over other existing state of art approaches. Further, the security of the proposed scheme remains high due to usage of multi-layered secret keys and chaos based random mapping handling worst tamper scenarios.     

Secure variable-capacity self-recovery watermarking scheme

Since existing watermarking schemes usually cannot recover the tampered position, a secure variable-capacity self-recovery watermarking scheme is proposed. Both watermark embedding capacity and security are taken into account. The original image is divided into texture blocks and smooth blocks, and the texture blocks not only save traditional information, and save the “details” information. The so-called “details” information refers to the texture information, which not only can effectively resist mean attack, but also help to improve the quality of the recovered image to meet the needs of practical work. And then according to the characteristics of different blocks, the different length compound watermarks are produced. The so-called “compound watermarks” include the authentication watermarks and information watermarks. Authentication watermarks are used to detect the tampered region, and the information watermarks which include basic watermark and additional watermark are used to recover image. Then the compound watermarks are inserted into the other blocks based on the new proposed scheme called three level secret-key embedding scheme (TLSES). And then detect the tamper blocks and recover them by the three level tamper detection scheme (TLTDS). The experimental results show that the paper can not only accurately detect the tamper region and recover image, but also can effectively resist mean attack and collage attack.

     

Adaptive reversible image watermarking scheme

This paper presents an adaptive block sized reversible image watermarking scheme. A reversible watermarking approach recovers the original image from a watermarked image after extracting the embedded watermarks. Without loss of generality, the proposed scheme segments an image of size 2^N × 2^N adaptively to blocks of size 2^L × 2^L, where L starts from a user-defined number to 1, according to their block structures. If possible, the differences between central ordered pixel and other pixels in each block are enlarged to embed watermarks. The embedded quantity is determined by the largest difference in a block and watermarks are embedded into LSB bits of above differences. Experimental results show that the proposed adaptive block size scheme has higher capacity than conventional fixed block sized method.