Using anisotropic diffusion for efficient extraction of sensor noise in camera identification

Each digital camera has an intrinsic fingerprint that is unique to each camera. This device fingerprint can be extracted from an image and can be compared with a reference device fingerprint to determine the device origin. The complexity of the filters proposed to accomplish this is increasing. In this note, we use a relatively simple algorithm to extract the sensor noise from images. It has the advantages of being easy to implement and parallelize, and working faster than the wavelet filter that is common for this application. In addition, we compare the performance with a simple median filter and assess whether a previously proposed fingerprint enhancement technique improves results. Experiments are performed on approximately 7500 images originating from 69 cameras, and the results are compared with this often used wavelet filter. Despite the simplicity of the proposed method, the performance exceeds the common wavelet filter and reduces the time needed for the extraction.     

重型颅脑损伤数字计算ERP特征及与智商的相关性

目的 根据ERP理论和韦氏智力量表内容建立数字计算ERP范式,探讨正常人与重型颅脑损伤患者数字计算ERP特征及与智商的相关性.方法 采用Neuroscan-ERP仪和韦氏智力量表对29名重型颅脑损伤患者(外伤组)和46名正常人(对照组)进行ERP及智商检测,比较引出的ERP成分特征及与智商的相关性.结果 数字计算范式的题目、正确、错误答案3类刺激引出的ERP波形包括外源性成分N1c、P2c及内源性成分N2c和P3c;对照组引出的N1c和P2c波幅和潜伏期相近,但N2c和P3c有明显差异,其中正确答案的P3c波幅最高,错误答案的P3c潜伏期最长;外伤组引出的各ERP成分波幅降低、潜伏期延长,N2c和P3c具有显著性差异(P＜0.05);对照组错误答案引出的P3c潜伏期与言语智商和总智商呈中度负相关,高于题目和正确答案;外伤组P3c潜伏期与言语智商、操作智商和总智商的相关系数分别为-0.64、-0.46和-0.60(P ＜0.05),明显高于对照组.结论 数字计算ERP范式可引出特征性ERP波形,其P3c潜伏期与智商有一定相关性,可作为评价重型颅脑损伤后数学能力损害程度的参考指标.     

QQ取证及其司法鉴定方法研究

简要介绍QQ取证及其司法鉴定研究的发展现状。分析QQ消息传输协议、数据库文件结构、Msg2.0.db文件的加密机制,重点研究QQ聊天记录及其他证据信息获取的思路和方法。在结合QQ取证鉴定案例的基础上,提出将手机与QQ进行融合取证的新思路,并对QQ取证及其司法鉴定的发展方向进行展望。     

An inconclusive digital audio authenticity examination: a unique case

This case report sets forth an authenticity examination of 35 encrypted, proprietary-format digital audio files containing recorded telephone conversations between two codefendants in a criminal matter. The codefendant who recorded the conversations did so on a recording system he developed; additionally, he was both a forensic audio authenticity examiner, who had published and presented in the field, and was the head of a professional audio society's writing group for authenticity standards. The authors conducted the examination of the recordings following nine laboratory steps of the peer-reviewed and published 11-step digital audio authenticity protocol. Based considerably on the codefendant's direct involvement with the development of the encrypted audio format, his experience in the field of forensic audio authenticity analysis, and the ease with which the audio files could be accessed, converted, edited in the gap areas, and reconstructed in such a way that the processes were undetected, the authors concluded that the recordings could not be scientifically authenticated through accepted forensic practices.     

以太网网络接口卡MAC永久地址与MAC当前地址的检验方法综述

本文综述了检验以太网网络接口卡MAC永久地址和MAC当前地址的方法,针对不同的检验客体提出了可行的检验方法。并提出了MAC在先检验的发展方向。     

A Comparison Between Digital Radiography,Computed Tomography,and Magnetic Resonance in the Detection of Gunshot Residues in Burnt Tissues and Bone

The radiological search for GSR is crucial in burnt material although it has been rarely tested. In this study, thirty‐one bovine ribs were shot at near‐contact range and burnt to calcination in an oven simulating a real combustion. Computed tomography (CT) and magnetic resonance (MR) were performed before and after carbonization and compared with former analyses with DR (digital radiography); thus comparing the assistance, the radiological methods can provide in the search for GSR in fresh and burnt bone. DR demonstrated the greatest ability in the detection of metallic residues, CT showed lower abilities, while MR showed a high sensitivity only in soft tissues. Thus, DR can be considered as the most sensitive method in the detection of GSR in charred bones, whereas CT and MR demonstrated much less reliability. Nonetheless, the MR ameliorates the analysis of gunshot wounds in other types of remains with large quantities of soft tissues.     

微滴式数字PCR技术用于生物样品种属鉴定和绝对定量

目的 运用微滴式数字PCR技术进行生物样品的种属鉴定和绝对定量.方法 选择人mtDNA两个编码基因ND4和16S rRNA,设计特异性引物与探针,用人来源及常见动物样本验证种属特异性,再用重组质粒和2组共16份人来源生物检材,倍比稀释.使用微滴式数字PCR技术进行种属检验和绝对定量,验证其灵敏度和稳定性.结果 人重组质粒FAM （ND4）可进行人来源样品的检测,其检测结果与各级稀释梯度基本吻合,微滴式数字PCR技术可以检测出反应体系中低至单拷贝的DNA.结论 微滴式数字PCR技术可以进行生物样品的种属鉴定和绝对定量,并具有很高的灵敏度和特异性,可应用于日常法医物证检验.     

针对进程用户空间的电子数据取证方法研究

进程用户空间中的信息往往与特定用户的特定操作行为直接关联,对于证据链的建立意义重大.从数目繁多的用户空间数据结构中筛选出最重要的三种：进程环境块、线程环境块与虚拟地址描述符,说明其定位方法,并重点讨论其结构格式的电子数据取证特性,为内存空间电子数据取证提供了新的思路与方法.实例分析部分,则以目前广泛使用的Windows 7操作系统为应用背景,说明了所述方法的具体应用.     

数字录音真实性司法鉴定研究现状

随着数字录音设备的普及,以及音频编辑技术的大众化趋势,传统的检验方法和技术在当前数字录音真实性司法鉴定实践中面临着极大的挑战。模式识别和人工智能等领域的最新进展为数字录音真实性鉴定提供了有效的检验角度。通过分析和总结当前机器学习和模式识别等研究领域在数字录音真实性研究方面的前沿探索性成果,结合对当前录音真实性司法鉴定实践应用中的关键技术和方法的论述,分析和探讨数字录音真实性司法鉴定领域研究所面临的问题、挑战及未来发展趋势。指出专家经验判断分析技术和统计量化检验方法的协作并存是数字录音真实性鉴定的必然趋势和高效解决方案。     

Windows Surface RT tablet forensics

Small scale digital device forensics is particularly critical as a result of the mobility of these devices, leading to closer proximity to crimes as they occur when compared to computers. The Windows Surface tablet is one such device, combining tablet mobility with familiar Microsoft Windows productivity tools. This research considers the acquisition and forensic analysis of the Windows Surface RT tablet. We discuss the artifacts of both the Windows RT operating system and third-party applications. The contribution of this research is to provide a road map for the digital forensic examination of Windows Surface RT tablets.