Adaptive data hiding based on VQ compressed images

Data hiding involves embedding secret data into various forms of digital media such as text, image, audio, and video. With the rapid growth of network communication, data-hiding techniques are widely used in protecting copyright, embedding captions and communicating secretly. The authors propose an adaptive algorithm to embed data into VQ compressed images. This method adaptively varies the embedding process according to the amount of hidden data. The proposed method provides more effective hiding and higher quality images than conventional methods. The results of experimental comparisons are also presented.     

Improved hiding data in images by optimalmoderately-significant-bit replacement

An improved data hiding technique by optimal moderately-significant-bit replacement is presented, which can significantly reduce the computational cost and enhance the visual quality of the resulting stego-image     

Efficient reversible data hiding in encrypted images

This paper proposes a novel scheme of reversible data hiding in encrypted images based on lossless compression of encrypted data. In encryption phase, a stream cipher is used to mask the original content. Then, a data hider compresses a part of encrypted data in the cipher-text image using LDPC code, and inserts the compressed data as well as the additional data into the part of encrypted data itself using efficient embedding method. Since the majority of encrypted data are kept unchanged, the quality of directly decrypted image is satisfactory. A receiver with the data-hiding key can successfully extract the additional data and the compressed data. By exploiting the compressed data and the side information provided by the unchanged data, the receiver can further recover the original plaintext image without any error. Experimental result shows that the proposed scheme significantly outperforms the previous approaches.     

话音通信中的数据自适应隐藏算法

基于话音通信的PCM量化编码,导出了数据嵌入强度因子的选取准则,给出了两种自适应选取的实现策略,进而提出了根据载体信号的幅度以及信道的噪声强度自适应调整的数据隐藏算法.隐藏信息为二进制比特数据时,仿真实验结果表明该自适应隐藏方法具有良好的隐蔽信息传输性能.     

Capacity estimates for data hiding in compressed images

We present an information-theoretic approach to obtain an estimate of the number of bits that can be hidden in still images, or, the capacity of the data-hiding channel. We show how the addition of the message signal or signature in a suitable transform domain rather than the spatial domain can significantly increase the channel capacity. Most of the state-of-the-art schemes developed thus far for data-hiding have embedded bits in some transform domain, as it has always been implicitly understood that a decomposition would help. Though most methods reported in the literature use DCT or wavelet decomposition for data embedding, the choice of the transform is not obvious. We compare the achievable data hiding capacities for different decompositions like DCT, DFT, Hadamard, and subband transforms and show that the magnitude DFT decomposition performs best among the ones compared.     

大数据时代用户信息安全与隐私保护

随着大数据的发展,人们日常生活、工作习惯和思考模式都受到不同程度的影响。目前,通过各种渠道收集、存储、处理以及维护大数据的技术尚不完善,数据分析的准确性也有待提高。文中简述了实现大数据时代信息安全与用户隐私保护面临的技术挑战,结合多种技术手段解决信息安全问题,为安全领域的发展带来了新的契机。     

An integer wavelet transform based scheme for reversible data hiding in encrypted images

In this paper, a novel reversible data hiding (RDH) scheme for encrypted digital images using integer wavelet transform, histogram shifting and orthogonal decomposition is presented. This scheme takes advantage of the Laplacian-like distribution of integer wavelet high-frequency coefficients in high frequency sub-bands and the independence of orthogonal coefficients to facilitate data hiding operation in encrypted domain, and to keep the reversibility. Experimental results has demonstrated that this scheme outperforms all of other existing RDH schemes in encrypted domain in terms of higher PSNR at the same amount of payload. Compared with the state-of-the-arts, the proposed scheme can be applied to all natural images with higher embedding rate.     

Content protection in grayscale and color images based on robust digital watermarking

The concept of digital rights management architecture for multimedia will be presented in this paper, with focus on robust digital image watermarking, which is able to undergo geometrical attacks performed against the embedded watermarks. Geometrical attacks are still an open problem for many digital watermarking algorithms used in present time. Most of geometrical attacks can be described by using affine transforms. A new approach to improve robustness against geometrical attacks is presented. The discrete Fourier transform and log-polar mapping are used for watermark embedding and for watermark detection. Some attacks against the embedded watermarks are performed and the results are given. Also two modifications, usage of the proposed method as a synchronization template and implementation for the color images, are presented and experimental results are given too.     

High-capacity data hiding in halftone images using minimal-error bit searching and least-mean square filter.

In this paper, a high-capacity data hiding is proposed for embedding a large amount of information into halftone images. The embedded watermark can be distributed into several error-diffused images with the proposed minimal-error bit-searching technique (MEBS). The method can also be generalized to self-decoding mode with dot diffusion or color halftone images. From the experiments, the embedded capacity from 33% up to 50% and good quality results are achieved. Furthermore, the proposed MEBS method is also extended for robust watermarking against the degradation from printing-and-scanning and several kinds of distortions. Finally, a least-mean square-based halftoning is developed to produce an edge-enhanced halftone image, and the technique also cooperates with MEBS for all the applications described above, including high-capacity data hiding with secret sharing or self-decoding mode, as well as robust watermarking. The results prove much sharper than the error diffusion or dot diffusion methods.     

Novel wavelet-based QIM data hiding technique for tamper detection and correction of digital images

This paper proposes a tamper detection and correction technique using semi-fragile data hiding that aims to achieve high perceptual quality of images at the user-end even after malicious modifications. A binary signature and an image digest are embedded by modulating integer wavelet coefficients using dither modulation based quantization index modulation. Half-toning technique is used to obtain image digest from the low-resolution version of the host image itself. Decoder extracts the binary signature from the watermarked image for tamper detection, while the extracted image digest is used to correct the tamper region. Unlike previously proposed techniques, this novel approach distinguishes malicious changes from various common image processing operations more efficiently and also correct tapered regions effectively. Experimental results show that the proposed technique provides a superior performance in terms of probability of miss and false alarm as well as in tamper correction, compared to several existing semi-fragile watermarking techniques.     

Adaptive progressive filter to remove impulse noise in highly corrupted color images

In this paper, an adaptive progressive filtering (APF) technique with low computational complexity is proposed for removing impulse noise in highly corrupted color images. Color images that are corrupted with impulse noise are generally filtered by applying a vector-based approach. Vector-based methods tend to cluster the noise and receive a lower noise reduction performance when the noise ratio is high. To improve the performance, in the proposed technique, a new reliable estimation of impulse noise intensity and noise type is made initially, and then a progressive restoration mechanism is devised, using multi-pass non-linear operations with selected processing windows adapted to the estimation. The effect of impulse detection based on geometric characteristics and features of the corrupt pixel/pixel regions and the exact estimation of impulse noise intensity and type are used in the APF to efficiently support the progressive filtering mechanism. Through experiments conducted using a range of color images, the proposed filtering technique has demonstrated superior performance to that of well-known benchmark techniques, in terms of standard objective measurements, visual image quality, and the computational complexity.     

Performance analysis of a 2-D-multipulse amplitude modulationscheme for data hiding and watermarking of still images

A watermarking scheme for copyright protection of still images is modeled and analyzed. In this scheme a signal following a key-dependent two-dimensional multipulse modulation is added to the image for ownership enforcement purposes. The main contribution of this paper is the introduction of an analytical point of view to the estimation of performance measurements. Two topics are covered in the analysis: the ownership verification process, also called watermark detection test, and the data hiding process. In the first case, bounds and approximations to the receiver operating characteristic are derived. These results can be used to determine the threshold associated to a required probability of false alarm and the corresponding probability of detection. The data hiding process is modeled as a communications system and approximations for the bit error rate are derived. Finally, analytical expressions are contrasted with experimental results     

大数据时代隐私信息安全防范与保障技术研究

为了做好大数据时代隐私信息安全防范,文章通过介绍目前我国比较常用的5种隐私信息安全技术,分析大数据的特点及存在问题,然后根据社会上容易引发隐私信息泄露的原因进行综合分析,找出加强大数据隐私信息安全的方式,促进大数据时代隐私信息安全防范效果的提升。     

大数据环境下的计算机网络安全问题与防护措施分析

随着信息技术的飞速发展以及普及应用,我国全面进入信息化社会,并因此产生了很多新生事物和新业态,其中,大数据就是一个非常重要的成果。在大数据环境下,计算机网络安全受到了更大的威胁,同时,其重要性也进一步提高,在这种背景下,需要结合大数据环境和我国计算机网络发展现状,制定科学、有效的防护措施,从而有效保证计算机网络和用户的数据安全,促进我国信息化的健康发展。文章针对上述情况,提出了计算机网络安全与防护措施。     

网络信息安全防范与Web数据挖掘系统的设计与实现

传统的信息挖掘方法挖掘面窄,扩展性差,无法有效挖掘出网络中的不安全信息。因此,设计并实现了网络信息安全防范与Web数据挖掘系统,其由Web文本采集模块、文本分类模块和类别判断模块构成。Web文本采集模块从网络Web网页中采集文本信息,并将信息反馈给文本分类模块。文本分类模块由训练模块、分类模块和分类器构成。训练模块采用完成分类的文本对文本分类模型进行训练,获取不同类别特征词间的关联性,塑造向量空间模型。分类模块对将要进行分类的Web文本进行分词处理,通过向量描述文本特征词。分类器运算待分类文本特征向量同各类中心向量间的相似度,确保Web文本被划分到具有最高相似度的文本类型中。类别判断模块辨识待分析的网络文本信息是否属于不安全信息类,并通过报警模块对不安全信息进行报警。软件部分给出了系统的功能结构以及文本分类模块的程序实现代码。实验结果表明,所设计系统具有较高的查全率、查准率和较高的检测性能。     

Hiding data in images by optimal moderately-significant-bitreplacement

A data hiding technique for the storage and transmission of important data is proposed. It embeds the important data in the moderately-significant-bit of an image, and applies a global substitution step and a local pixel adjustment process to reduce any image degradation. Experimental results show that the visual quality of the resulting image is acceptable     

利用偏振滤波实现黑白和彩色图像增强

本文提出一种利用偏振滤波法实现零频衰减从而获得图像的边缘增强的方法。制作简单,且可连续控制边缘增强图像的对比度。     

Detection and classification of edges in color images

Up to now, most of the color edge detection methods are monochromatic-based techniques, which produce, in general, better than when traditional gray-value techniques are applied. In this overview, we focus mainly on vector-valued techniques because it is easy to understand how to apply common edge detection schemes to every color component. Opposed to this, vector-valued techniques are new and different. The second part of the article addresses the topic of edge classification. While edges are often classified into step edges and ramp edges, we address the topic of physical edge classification based on their origin into shadow edges, reflectance edges, orientation edges, occlusion edges, and specular edges. In the rest of this article we discuss various vector-valued techniques for detecting discontinuities in color images. Then operators are presented based on vector order statistics, followed by presentation by examples of a couple of results of color edge detection. We then discuss different approaches to a physical classification of edges by their origin.     

Reversible data hiding for encrypted signals by homomorphic encryption and signal energy transfer

Reversible data hiding for encrypted signals with prefect reconstruction of directly decrypted signals is introduced in this paper. Each unit in the original image is separated into three components by energy transfer equation, and each component is encrypted by Paillier homomorphic encryption. Additional bits are concealed into the encrypted image by manipulating the encrypted signals. Finally, the original image can be perfectly recovered when direct decryption is applied. The embedded bits are lossless extracted as well. Optimal visual quality and improved embedding rate are obtained by the proposed approach, since the value of the directly decrypted unit is the same as the original one. Experimental results and comparisons are demonstrated to illustrate the effectiveness and advantages of the proposed method. Moreover, the proposed method can be extended to deal with encoded multimedia, which further enriches the application scenarios.