一种基于超混沌系统的立体图像零水印算法

为了在不改变立体图像质量的前提下对立体图像实施版权保护,提出了一种基于超混沌离散系统的立体图像零水印算法. 该算法利用立体图像左右视点小波变换域低频子带视差的稳定性以及离散余弦变换直流系数稳定的特点构造了一种视差零水印. 在水印构造过程中,利用了超混沌离散系统的初始值敏感性、参数密钥空间大和动力学行为复杂等特性映射视差零水印的 位置信息,从而增强了水印算法的安全性.此外,还分析了水印安全性与水印容量之间的关系. 实验结果表明,该立体图像视差零水印算法对加噪、滤波、压缩、剪切、图像放大和缩小等各种对称和非对称攻击表现出了 较强的鲁棒性.     

基于方差的奇异值分解域鲁棒零水印算法

针对已提出的奇异值分解域鲁棒水印算法往往将水印嵌入在奇异值矩阵的奇异值上,利用奇异值分解产生的两个正交矩阵提出一种基于方差的鲁棒零水印算法.将图像分割成互不重叠的子块,对每个子块进行奇异值分解,通过判断每个子块U矩阵第一列元素平方的方差与V矩阵第一列元素平方的方差之间的大小关系产生零水印序列.算法实质上没有对原始图像做...     

基于方差的奇异值分解域鲁棒零水印算法

 针对已提出的奇异值分解域鲁棒水印算法往往将水印嵌入在奇异值矩阵的奇异值上,利用奇异值分解产生的两个正交矩阵提出一种基于方差的鲁棒零水印算法.将图像分割成互不重叠的子块,对每个子块进行奇异值分解,通过判断每个子块U矩阵第一列元素平方的方差与V矩阵第一列元素平方的方差之间的大小关系产生零水印序列.算法实质上没有对原始图像做任何修改,具有非常好的不可见性.算法进行抵抗重采样、平滑处理、加噪音和JPEG压缩攻击实验测试鲁棒性.实验结果表明该算法在以上攻击中表现出很强的鲁棒性.     

基于HVS的小波变换数字图像水印算法

为实现图像水印在数据认证、访问控制和版权保护等领域发挥作用,提出一种人眼视觉感知特性的小波变换数字图像水印算法。首先对二值图像水印进行Arnold变换,并采用行堆叠的方法,转换成一维序列,然后根据密钥生成的高斯序列中值的正负来确定水印信息嵌入时是采用那种调制方式,最后对原始图像进行3级DWT分解,在小波图像的第二层中频子带中,结合人眼视觉特性将水印正向或负向调制叠加在宿主图像大于JND 值的小波系数上。实验结果表明:该算法能抵抗JPEG压缩、加噪、剪切等多种攻击,具有良好的透明性,鲁棒性和安全性。     

抗JPEG压缩和几何攻击的鲁棒零水印算法

针对数字图像传输时经常面临JPEG压缩和几何攻击,提出一种抗JPEG压缩和几何攻击的鲁棒零水印算法.将原始图像分割成互不重叠的子块,对每个子块进行奇异值分解,对奇异值矩阵进行harr小波变换,通过比较相邻两个子块奇异值矩阵小波低频逼近子带对角线元素的均值大小关系产生零水印序列.数学理论分析表明:通过比较相邻两个子块奇异值矩阵所有奇异值的均值大小关系产生零水印序列,算法实质上没有对原始图像做任何改动,具有非常好的不可见性.实验结果表明,该算法在抵抗JPEG压缩和旋转、尺寸缩放、随机删除行列、偏移行列、打印-扫描几种几何攻击表现出比较强的鲁棒性.     

基于混沌Logistic和Arnold二次加密的图像水印算法研究

针对图像水印在不可见性和鲁棒性方面很难同时满足的问题。提出一种基于混沌对原始水印图像进行双重加密的方法,使水印信息具有双重的保密性;根据人眼视觉系统将不同强度的水印分量自适应地嵌入到DCT的中频系数中,使嵌有水印的图像具有良好的视觉不可见性。实验表明,该算法在水印自身的安全性和相关性,系统的鲁棒性方面相对于其它算法都有很大的提高。     

基于量子随机行走和多维混沌的三维图像加密算法

随着互联网的发展,人们对于信息安全的需求日益增加,而经典的加密技术存在着密钥空间小、易破解的缺陷,图像加密技术在保护图像信息安全和隐私内容等方面的问题亟待解决.量子随机行走作为一种新型量子密钥生成器,其密钥空间大,与经典随机行走相比计算速度与安全性有着明显的提高.本文提出一种基于量子随机行走并涉及Lorenz和Rossler多维混沌的三维图像加密算法.首先应用高斯金字塔对图像进行处理然后按照一定比例将处理后的图像切割成4份;其次使用量子随机行走生成的随机序列与多维混沌中的Lorenz混沌系统生成的随机序列对分成的若干块子图像进行汉明距离计算然后进行合成,并且对图像RGB三通道之间进行欧氏距离计算;最后将汉明距离与欧式距离取余得到的序列值作为初始值输入多维混沌中的Rossler系统,生成随机序列作为密钥对图像的RGB通道进行异或操作得到加密后的图像,对应解密方案为加密过程逆过程.此外,本文采用基于离散余弦变换和奇异值分解的盲水印嵌入算法将水印信息嵌入到加密后的图像中,实现接收方可以通过提取水印,根据水印信息的完整性来判断传输过程中图像是否遭受到攻击破坏,如无遭受恶意攻击,则对图像进行解密...     

自嵌入双功能图像水印算法

利用自嵌入技术提出一种同时实现版权保护和内容认证的双功能图像水印算法.在嵌入端,首先将原始图像划分成互不重叠的子块,将各子块每个像素的最低m位置0,然后将最低m位置0后的子块进行奇异值分解,通过提取奇异值范数的最高位奇偶性产生原始鲁棒特征水印,然后再将原始鲁棒特征水印嵌入各子块每个像素的最低m位得到含水印图像.检测端从攻击的含水印图像提取鲁棒特征水印的过程与嵌入端产生原始鲁棒特征水印的过程类似,并且通过计算提取的鲁棒特征水印与原始鲁棒特征水印之间的归一化相关度进行版权鉴别,通过判断提取的鲁棒特征水印与攻击图像各子块每个像素的最低m位的一致性实现篡改检测进行内容认证.理论分析和实验结果都表明算法具有非常好的不可见性.实验结果还表明,算法不仅在抵抗添加噪音、剪切、JPEG压缩、平滑、重采样和几何攻击如随机删除行、向右偏移列、向下偏移行表现出很强的鲁棒性,而且能够精确定位出篡改位置和区分篡改类型.因此,算法具有版权保护和内容认证双重功能.     

基于Radon变换和四元数实矩阵的彩色图像零水印算法

为了提高空间域彩色图像零水印算法的水印嵌入和检测精度以及抵抗旋转几何变换的能力,提出了一种基于Radon变换和四元数实矩阵表示的抗旋转攻击空间域零水印算法。首先将原始彩色图像使用四元数实矩阵来表征,并计算实数字矩阵的Radon变换不变矩;然后利用少量低阶Radon变换不变矩来设计和构建零水印信息;在水印检测前,通过Radon变换几何校正算法对可能遭受旋转攻击的待检测图像进行旋转角度的校正,然后进行水印的提取。实验结果表明,该方法可以获得良好的图像视觉效果,对于旋转几何攻击具有很强的鲁棒性,同时对滤波、JPEG压缩和剪切攻击也具有一定的鲁棒性。     

基于数字全息及离散余弦变换的图像数字水印技术

提出了一种以数字全息和离散余弦变换为基础的数字水印技术,实现了在原始图像中嵌入数字全息水印。考虑到数字全息图的不可撕毁性,使得数字全息水印本身就具有良好的抗剪切能力,并且与传统的二维灰度水印相比嵌入的信息更多。数字全息图通过傅里叶变换全息的方法获得,为了提高抗有损压缩能力,在数字全息水印嵌入过程中采用了基于(JPEG模型和分解离散余弦变换(DCT)系数的方法。实验表明,通过该算法获得的数字全息水印对JPEG有损压缩和剪切等图像处理操作均有很好的稳健性,并且采用密钥加强了水印的安全性。因此该算法能成为数字多媒体产品版权保护的有效方案。     

Block based embedding of encrypted watermarks using singular value decomposition

Watermarking is a solution to the problem of copyright protection of multimedia documents over the Internet. This paper presents a block based watermarking scheme using the singular value decomposition (SVD) algorithm to embed encrypted watermarks into digital images. The paper compares between the traditional method of Liu and the proposed method for embedding encrypted watermarks. Also, a permutation based encryption algorithm and a diffusion based encryption algorithm are compared as the watermark encryption algorithms. Experimental results show that the proposed method is superior to the traditional method of Liu for embedding encrypted watermarks and extracting them efficiently under attacks. Results also show that it is preferred to use permutation based encryption algorithms than diffusion based encryption algorithms for watermark encryption due to their lower sensitivity to attacks.     

基于虚拟光学的三维空间数字水印系统

数字水印已成为数字作品版权保护的一种手段。数字水印是一种嵌入到图像、视频或者音频数据中的不可见标志 ,通过对水印信息的检测可以达到保护多媒体数据版权的目的。先前众多的水印算法大部分是基于二维操作的 (如静止图像、视频 )。基于虚拟光学信息隐藏理论提出了一种三维空间的数字水印算法。该数字水印算法能成为一种多媒体数据产权保护的有效方案。对算法的测试结果表明 ,该算法对于噪声叠加、剪切、有损压缩等常见的信号处理操作具有较高的鲁棒性。同时 ,该算法由于引入了虚拟光学信息隐藏思想 ,将虚拟光路的几何结构参量作为密钥 ,设计出了多重“锁”和多重“密钥” ,大大提高了水印系统的密钥空间 ,仿真结果表明该算法具有良好的安全性。     

Optical asymmetric watermarking using modified wavelet fusion and diffractive imaging

In most of the existing image encryption algorithms the generated keys are in the form of a noise like distribution with a uniform distributed histogram. However, the noise like distribution is an apparent sign indicating the presence of the keys. If the keys are to be transferred through some communication channels, then this may lead to a security problem. This is because; the noise like features may easily catch people׳s attention and bring more attacks. To address this problem it is required to transfer the keys to some other meaningful images to disguise the attackers. The watermarking schemes are complementary to image encryption schemes. In most of the iterative encryption schemes, support constraints play an important role of the keys in order to decrypt the meaningful data. In this article, we have transferred the support constraints which are generated by axial translation of CCD camera using amplitude-, and phase- truncation approach, into different meaningful images. This has been done by developing modified fusion technique in wavelet transform domain. The second issue is, in case, the meaningful images are caught by the attacker then how to solve the copyright protection. To resolve this issue, watermark detection plays a crucial role. For this purpose, it is necessary to recover the original image using the retrieved watermarks/support constraints. To address this issue, four asymmetric keys have been generated corresponding to each watermarked image to retrieve the watermarks. For decryption, an iterative phase retrieval algorithm is applied to extract the plain-texts from corresponding retrieved watermarks.     

Blind and Secured Adaptive Digital Image Watermarking Approach for High Imperceptibility and Robustness

In the past decade, rapid development in digital communication has led to prevalent use of digital images. More importantly, confidentiality issues have also come up recently due to the increase in digital image transmission across the Internet. Therefore, it is necessary to provide high imperceptibility and security to digitally transmitted images. In this paper, a novel blind digital image watermarking scheme is introduced tackling secured transmission of digital images, which provides a higher quality regarding both imperceptibility and robustness parameters. A block based hybrid IWT- SVD transform is implemented for robust transmission of digital images. To ensure high watermark security, the watermark is encrypted using a Pseudo random key which is generated adaptively from cover and watermark images. An encrypted watermark is embedded in randomly selected low entropy blocks to increase the security as well as imperceptibility. Embedding positions within the block are identified adaptively using a Blum–Blum–Shub Pseudo random generator. To ensure higher visual quality, Initial Scaling Factor (ISF) is chosen adaptively from a cover image using image range characteristics. ISF can be optimized using Nature Inspired Optimization (NIO) techniques for higher imperceptibility and robustness. Specifically, the ISF parameter is optimized by using three well-known and novel NIO-based algorithms such as Genetic Algorithms (GA), Artificial Bee Colony (ABC), and Firefly Optimization algorithm. Experiments were conducted for the proposed scheme in terms of imperceptibility, robustness, security, embedding rate, and computational time. Experimental results support higher effectiveness of the proposed scheme. Furthermore, performance comparison has been done with some of the existing state-of-the-art schemes which substantiates the improved performance of the proposed scheme.     

A Quantum Watermarking Protocol Based on Bell Dual Basis

This paper presents a Bell-dual-basis-based quantum watermarking protocol composed of three major algorithms: watermark embedding and extracting and the intercepting test. The first two are completed by using the entanglement swapping property of Bell dual basis and the test is accomplished through IBF protocol to guarantee its bottom security. The watermarking protocol is mainly designed for the protection of digital copyright in the existence of classical information. This design finds that the quality of digital contents is not damaged with its zero-watermark attributes when embedding watermarks.     

A blind color image watermarking based on DC component in the spatial domain

Color image watermarking has become essential and important copyright protection or authentication scheme. It is noted that most of the existing color image watermarking algorithms are performed only in the single domain (spatial domain or frequency domain), and not to integrate these merits of the different domains. By utilizing the generating principle and distribution feature of the direct current (DC) coefficient, a novel blind watermarking algorithm is proposed for color host images in this paper. Firstly, the Y luminance of host image is divided into 8 × 8 sub-blocks and the DC coefficients of each block are directly calculated in the spatial domain without DCT transform. Secondly, according to the watermark information and the quantization step, the DC coefficients are calculated and their increments are further utilized to modify directly the values of all pixels in the spatial domain instead of the DCT domain to embed watermark. When watermark extraction, only the watermarked image and the quantization step are needed in the spatial domain. Experimental results show that the proposed method not only can resist both traditional signal processing attacks and geometric attacks, but also has more efficient in computational complexity. Comparisons also demonstrate the advantages of the method.     

A novel blind color images watermarking based on SVD

Since the color image watermark has more bit information, it is a challenging problem to design a robust and blind color watermarking scheme for copyright protection. In this paper, a blind watermarking scheme based on singular value decomposition (SVD) is proposed. By analyzing the orthogonal matrix U via SVD, it is found that there exists a strong similarity correlation between the second row first column element and the third row first column element. Hence, this paper utilizes this property for image watermarking. Firstly, the 4 × 4 non-overlapping pixels block of each component in color host image is processed by SVD. And then, the color watermark is embedded by slightly modifying the value of the second row first column element and the third row first column one of U matrix, and the modified relation can be utilized to extract watermark. Experimental results, compared with the related existing methods, show that the proposed color image scheme has stronger robustness against most common attacks such as image compression, filtering, cropping, noise adding, blurring, scaling and sharpening et al.     

Cryptanalysis and improvement of a binary watermark-based copyright protection scheme for remote sensing images

The copyright protection of the remote sensing images is becoming a hot research topic in recent years. By considering the characteristics of the binary image, Zhu et al. proposed a new digital watermarking algorithm to protect the copyright of remote sensing images effectively. However, Zhu et al.’s scheme is not secure under the novel attack method proposed in this paper. While keeping the visual quality of the protected original image unchanged, the embedded watermark can be replaced with another watermark if the attacker has the host image carrying the other watermark. Thus the copyright of the original image changes and the copyright protection fail. To overcome the insecurity, a chaos-based improvement measure is proposed, in which the performance is the same as before. Analysis, proof, and experiment show that our methods are feasible and effective.     

Performance analysis on a watermarking method based on double random phase encoding technique

When digital watermarking is used for piracy tracking, different watermarks are needed to be embedded into different distributions of a digital product. Based on double random phase encoding (DRPE) technique, cascaded-phases iterative algorithm and random-phase-shift algorithm, Chen et al. proposed a method to generate many different embedded watermarks from one reference watermark, while the embedded watermark can be recognized by testing the correlation between the recovered watermark and the original reference watermark. In this way, only the reference watermark instead of the embedded watermarks needs to be stored and managed. However, since the recovered watermark may be different from the embedded watermark, especially under any image processing, the correlation between the recovered watermark and the reference watermark may be different from the correlation between the embedded watermark and the reference watermark, which may result in wrong recognition. In this paper, the performance of Chen's method was analyzed with numerical simulations. The results indicated that, to correctly recognize the embedded watermark, the number of generated embedded watermarks with Chen's method is limited.     

Novel quantum watermarking algorithm based on improved least significant qubit modification for quantum audio

As one of essential multimedia in quantum networks, the copyright protection of quantum audio has gradually become an important issue in the domain of quantum information hiding in the decades. In this paper, an improved quantum watermarking algorithm based on quantum audio by using least significant qubit(LSQb) modification is proposed. Compared with the previous achievements, it can effectively improve the robustness and security of watermark for copyright protection of quantum audio. In the new algorithm, the least significant bites and the peripheral least significant bits of the amplitudes are modified in terms of their logical consistency and correlation to enhance watermark robustness of resisting various illegal attacks. Furthermore, the new algorithm can avoid the weak robustness defect of many previous algorithms that directly embedded the watermark into the least significant bits. In order to implement the new algorithm, some specific quantum circuits are designed to obtain better applicability and scalability for embedding and extracting watermark.Finally, the simulation results including the values of audio waveforms and signal to noise ratios(SNR) prove that the new algorithm has good transparency, robustness, and security.