面向JPEG图像篡改的盲取证技术综述

简要阐述了目前国内外学者在JPEG图像篡改的被动取证技术方面的主要研究成果。基于篡改和检测方法的不同,目前检测方法可分为双重JPEG压缩检测方法和JPEG块效应不一致性检测方法。对两类检测方法的代表性方法进行了性能评价,指出了其存在的问题,并对JPEG图像篡改盲取证技术进行了展望。     

数字图像篡改被动检测技术综述

现有数字图像篡改被动检测技术相关综述对传统检测手段的描述详实细致,但缺乏对以深度学习为导向的利用卷积神经网络检测技术的系统介绍。针对数字图像篡改被动检测问题,就基于特征提取的传统篡改检测和基于卷积神经网络的篡改检测两个主要研究方向进行了阐述,分析和总结了其主要研究工作和相关算法,并在此基础上指出了数字图像篡改被动检测未来可能的发展趋势。     

基于压缩特征的数字图像篡改取证研究

随着计算机网络和多媒体技术的迅速发展,数字图像的恶意篡改和伪造也越来越容易,判断图像真实性和完整性显得尤为重要．对最流行的JPEG图像进行研究,图像篡改操作会破坏、打乱图像数据之间彼此关联性和内在连续性,通过图像压缩特征的差值曲线发现：单次压缩后图像的差值曲线只有一个波谷,而双重JPEG．r~缩图像的差值曲线有两个波谷,因此可以根据图像的差值曲线来检测图像是否被篡改．     

基于光照方向不一致的图像盲取证技术

通过提取单一数字图像中目标物体的边缘信息,可估计图像拍摄场景中的光照方向. 为了提高光照方向的估计效率,引入图像边缘检测算子,实现了待取证图像中目标物体的准确定位和边缘拟合,并进行了数据分析,建立了系统的基于光照方向不一致的图像篡改检测流程. 实验结果表明,边缘检测算子优化了图像检测流程,提高了该取证技术的可行性和可扩展性.     

基于人工神经网络的数字图像盲取证

数字图像盲取证技术是一项通过图像本身统计特性来鉴别图像是否被篡改的技术。文章基于数码相机的成像原理,利用人工神经网络来预测成像过程中由于CFA(color filter arrays)插值算法导致图像像素点之间出现的相关性关系,由于没有篡改的图像采用的CFA插值算法是相同的,而被篡改的图像则可能存在两种以上的CFA插值算法,两种情况下图像预测误差会出现差异,本算法利用这种差异实现数字图像的盲取证。实验结果表明本算法具有一定的有效性。     

图像复制-粘贴篡改快速取证

提出了一种新的篡改检测算法,将图像分为大小相同的重叠块,然后提取每块的特征向量,并对所求出的特征向量通过基数排序来减少搜索空间,减少运算量。对排序后的特性向量求相邻的特征向量的差异(偏移向量),并对偏移向量进行统计,如果存在大量的相同偏移向量可认定为篡改区域。最后利用数学形态学操作获得最终的篡改定位结果。     

基于生命游戏的数字图像置乱与数字水印技术

针对近年兴起的数字图像安全保密和数字水印等问题,从另一个角度提出了一种数字置乱加密技术和数字水印植入技术。首先探讨一类特殊的图像矩阵变换－ＪｏｈｎＣｏｎｗａｙ提出的生命游戏;然后将生命游戏扩展为数字图像的位置置乱加密算法;此外,根据生命游戏的规则,提出了一种新颖的数字水印植入技术,从试验结果来看该算法可以在一定程度上满足数字图像加密和隐藏的鲁棒性要求。     

数字图像技术在显微图像处理中的应用

简要介绍了数字图像处理技术，比较了几个边缘检测处子的处理结果，给出了轮廓提取与轮廓跟踪的模拟，对数字图像处理中的阈值分割技术给给出了一种通过迭代图像最佳分割阈值的方法。     

一种基于融合的数字图像隐藏技术

利用数字图像的融合技术，介绍一种利用一幅放大的BMP彩色图像隐藏三幅BMP彩色图像的方法．该方法信息隐藏率高，隐蔽性较好，而且容易实现．     

一种基于LBP和马尔科夫特征的细缝裁剪取证方法

针对细缝裁剪图像篡改操作,提出了一种基于局部二值模式(Local Binary Pattern,LBP)和马尔科夫特征的数字图像篡改取证方法。首先利用LBP算子将图像从空域转换到LBP域,对其进行JPEG压缩后提取二维JPEG矩阵,计算该矩阵在水平、垂直、主对角线、次对角线方向上的一阶差分矩阵,最后对各个方向上差分矩阵分别提取马尔科夫特征,通过支持向量机进行分类训练,从而对细缝裁剪篡改进行检测。实验结果表明,该算法优于传统马尔科夫特征算法以及其他细缝裁剪检测算法,特别是在细缝裁剪比例较小时的检测率较已有算法有明显提升。     

Image Tampering Detection Using No-Reference Image Quality Metrics

In this paper,a new approach is proposed to determine whether the content of an image is authentic or modified with a focus on detecting complex image tampering.Detecting image tampering without any prior information of the original image is a challenging problem since unknown diverse manipulations may have different characteristics and so do various formats of images.Our principle is that image processing,no matter how complex,may affect image quality,so image quality metrics can be used to distinguish tampered images.In particular,based on the alteration of image quality in modified blocks,the proposed method can locate the tampered areas.Referring to four types of effective no-reference image quality metrics,we obtain 13 features to present an image.The experimental results show that the proposed method is very promising on detecting image tampering and locating the locally tampered areas especially in realistic scenarios.     

基于双遍历和膨胀滤波的图像拼接定位算法

针对图像拼接操作会对边缘像素的连续性造成破坏等问题,本文提出了一种基于双遍历峰值和膨胀滤波的彩色图像拼接定位算法.该算法首先对待检测图像进行行列差分,确定双遍历峰值,同时再进行R,G,B三通道拼接点融合,从而全面获取拼接点信息,并利用数学形态学的膨胀滤波,强化拼接边缘,削弱噪点的影响.仿真结果表明,彩色图像拼接定位算法,时空复杂度小,能够有效地检测图像拼接伪造区域、大小及形状,可以对伪造区域进行准确定位.该研究可应用于图像取证等相关行业.     

Fractional Order ［Proportional Integral］ Controllers Parameters Algorithm Based on the Vector Method

In forensic investigations,it is vital that the authenticity of digital evidence should be ensured. In addition,technical means should be provided to ensure that digital evidence collected cannot be misused for the purpose of perjury. In this paper,we present a method to ensure both authenticity and non-misuse of data extracted from wireless mobile devices. In the method,the device ID and a timestamp become a part of the original data and the Hash function is used to bind the data together. Encryption is applied to the data,which includes the digital evidence,the device ID and the timestamp. Both symmetric and asymmetric encryption systems are employed in the proposed method where a random session key is used to encrypt the data while the public key of the forensic server is used to encrypt the session key to ensure security and efficiency. With the several security mechanisms that we show are supported or can be implemented in wireless mobile devices such as the Android,we can ensure the authenticity and non-misuse of data evidence in digital forensics.     

电子数据取证的可信固定方法

在介绍传统电子数据固定方法的基础上,针对可信取证理念,给出电子数据静态属性可信的支撑框架和可信固定方法.运用DSA数字签名、时间戳技术,并结合基于证实数字签名的第3方保证方案,研究电子数据具体的可信固定算法.通过形式化分析,定义并描述电子数据静态属性可信的约束规则,为电子数据可信固定提供支持.结合取证实例,运用已总结的公理和规则进行可信取证的形式化分析.结果表明,该方法能对电子证据进行可信固定.     

电子数据取证研究综述

电子数据取证技术是信息安全研究领域的新课题,在安全事件应急响应和打击网络犯罪方面发挥巨大的作用,本文首先就电子数据取证的相关概念和工作特点进行了介绍,然后针对电子数据取证中的取证原则、取证模型、取证流程等核心问题进行了探讨,最后对取证的关键技术和新特点进行概述。     

CloudForen: A Novel Framework for Digital Forensics in Cloud Computing

Since its birth in the early 90 ＇s,digital forensics has been mainly focused on collecting and examining digital evidence from computers and networks that are controlled and owned by individuals or organizations.As cloud computing has recently emerged as a dominant platform for running applications and storing data,digital forensics faces well-known challenges in the cloud,such as data inaccessibility,data and service volatility,and law enforcement lacks control over the cloud.To date,very little research has been done to develop efficient theory and practice for digital forensics in the cloud.In this paper,we present a novel framework,Cloud Foren,which systematically addresses the challenges of forensics in cloud computing.Cloud Foren covers the entire process of digital forensics,from the initial point of complaint to the final point where the evidence is confirmed.The key components of Cloud Foren address some challenges,which are unique to the cloud.The proposed forensic process allows cloud forensic examiner,cloud provider,and cloud customer collaborate naturally.We use two case studies to demonstrate the applicability of Cloud Foren.We believe Cloud Foren holds great promise for more precise and automatic digital forensics in a cloud computing environment.     

Web Page Forensics: A Web Spider Based Approach

Cyber-crimes are growing rapidly,so it is important to obtain the digital evidence on the web page.Usually,people can examine the browser history on the client side and data files on the server side,but both of them have shortcomings in real criminal investigation.To overcome the weakness,this paper designs a web page forensic scheme to snapshot the pages from web servers with the help of web spider.Also,it designs several steps to improve the trustworthiness of these pages.All the pages will be dumped in local database which can be presented as reliable evidence on the court.     

数字水印技术中的一类并行算法

讨论了数字水印技术的一类并行算法，即费尔马素数检测定理的并行化算法，同时将此类算法用于数字水印制作技术之中。