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。     

动用现代高科技做公证 公证处里冒牌老爸现原形

随着南京市民的经济条件越来越好．“公证”越来越多地走进大家的生活。为了发挥公证的真实性、合法性，减少纠纷的出现，南京市钟山公证处专门购置了一套录音录像设备，对一些容易发生纠纷的公证进行实时的录音录像并且和公证书一起备案。     

录音剪辑检验的实验研究

目的寻找录音剪辑的检验方法。方法进行模拟仿真实验。分别用标准盒式录音机、微型录音机和MP3录制样本，再用物理剪辑、录音机具编辑、软件编辑等3种方法对样本进行剪辑，最后用VS3．0语音工作站进行检验。结果找到剪辑点痕迹特征在时域波形图、宽带语谱图、窄带语谱图上的反映。结论利用“语意连贯性检验”、“背景噪声图谱连贯性检验”、“突变声痕检验”等方法可以实现对录音剪辑的检验。     

苹果手机录制录音的真实性鉴定若干问题探究

为解释苹果手机所录录音真实性鉴定中发现的各种疑问,对i Phone12（送检手机）、i Phone SE、iPhone 6、iPhone 4s手机中的录音文件进行同步、修改录音质量、复制、修剪、替换、清除等实验操作,结果显示在上述手机中,语音备忘录的录音文件只允许同步一次,手机录制的“无损”与“压缩”设置只改变语音频率,并不改变录音采样率;同时总结出从上述手机语音备忘录录音列表中复制语音的文件名变化规则,对原始录音文件编辑后的各种变化,以及iTunes语音备忘录信息查看工具的重要性等一些规律性认识,为苹果手机所录录音的真实性鉴定提供了理论依据与实践经验。     

同步录音录像制度运行中的若干问题探析-以福建省职务犯罪案件为观察对象

我国法律没有规定刑事案件侦查讯问时同步录音录像的性质，所以对于同步录音的认识不一。这种情况已经对同步录音录像的规范运用产生重要的影响。基于实证调研的数据，可以对同步录音录像制度在实务中的运行状况、程序规范、存在的问题、同步录音录像的实务运用与效用进行全面的梳理。在此基础上，对同步录音录像性质与定位的争议等问题进行了回应。同步录音录像可作为侦查讯问行为合法性证据和口供补强证据，但一般情况下不能作为案件实体事实的证据。     

司法鉴定客观、公正的重要保障

正确理解和严格执行《司法鉴定程序通则》对司法鉴定的审查受理、实施鉴定、出具司法鉴定文书等三个阶段的具体规定,确保受理鉴定的合法性、实施鉴定的客观性和科学性、出具司法鉴定文书的真实性和有效性。是维护司法鉴定秩序、提高司法鉴定质量,促进司法鉴定客观、公正的重要保障。     

司法鉴定领域分类和能力范围表述的国内外比较研究

对司法鉴定领域开展科学、有效的分类,进行统一规范的能力范围表述,有助于建立完整的司法鉴定标准化体系,能为司法鉴定机构合理规划组织结构、准确定位发展方向提供指引,也能为司法鉴定行业管理部门的规范化管理提供帮助。对该领域分类和能力表述开展国内外比较分析,是实现上述目标的基础性研究。目前我国在司法鉴定领域的分类方法尚未统一,与国外法庭科学认可分类方法相比,尚有部分项目未纳入分类范围之内;国内能力范围表述在目的、方式、详细程度上与国外相比亦有不同。本文对国内外行业管理组织和国际权威认可机构司法鉴定领域分类及能力范围表述进行了比较分析,研究解析其内容及差异,并提出了制定司法鉴定领域分类国家标准、扩展司法鉴定领域分类内容、适时调整司法鉴定能力范围表述内容等建议。     

司法鉴定客观、公正的重要保障

正确理解和严格执行《司法鉴定程序通则》对司法鉴定的审查受理、实施鉴定、出具司法鉴定文书等三个阶段的具体规定,确保受理鉴定的合法性、实施鉴定的客观性和科学性、出具司法鉴定文书的真实性和有效性。是维护司法鉴定秩序、提高司法鉴定质量,促进司法鉴定客观、公正的重要保障。     

不同手机及不同通信网络通话录音质量评析

目的为送检手机通话录音质量的审查提供理论依据。方法提出一种定量化的语音检材质量评价标准,并对不同手机及不同通信网络下的录音进行质量评价。该标准基于主流鉴定设备,涵盖了声学语谱图共振峰个数及数值、基频参数、区域平均频谱等分析方法以及声纹比对测试。结果实验结果显示,不同条件下得到的通话录音质量存在一定的差异性,会对声纹图谱鉴定产生一定影响,但并不会造成本质性差异。结论语音同一认定中,对基于移动通信网络获取的检材录音应考虑到通话语音质量的差异性对检验的影响,并在鉴定分析中加以评估和克服。     

同步录音录像口供功能的证成及适用

作为一项口供证据,同步录音录像与讯问笔录在反映被告人口供内容的诉讼功能上并无不同,但相比主观化的讯问笔录,采用客观中立的同步录音录像显然更能顺应法院裁判对真实性偏好的选择,不应以其形式特殊一概否定同步录音录像口供功能的正当性。同步录音录像作为口供构成诉讼案卷的组成部分,是讯问笔录的补充性证据载体,应当建立差异化随案移送和完备的开示规则。要发挥同步录音录像的口供功能,需要从同步录音录像作为口供的完整性要求出发确立一些证据能力规则,并明确强制性排除的违反法律后果,强化外在制度保障。同时,实质性差异的界分标准为同步录音录像作为口供提供了不同的证明力规则,需要重视其在限制被告人翻供问题上的积极意义。     

Speech Watermarking: An Approach for the Forensic Analysis of Digital Telephonic Recordings*

Abstract: In this article, the authors discuss the problem of forensic authentication of digital audio recordings. Although forensic audio has been addressed in several articles, the existing approaches are focused on analog magnetic recordings, which are less prevalent because of the large amount of digital recorders available on the market (optical, solid state, hard disks, etc.). An approach based on digital signal processing that consists of spread spectrum techniques for speech watermarking is presented. This approach presents the advantage that the authentication is based on the signal itself rather than the recording format. Thus, it is valid for usual recording devices in police‐controlled telephone intercepts. In addition, our proposal allows for the introduction of relevant information such as the recording date and time and all the relevant data (this is not always possible with classical systems). Our experimental results reveal that the speech watermarking procedure does not interfere in a significant way with the posterior forensic speaker identification.     

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.     

Application of the Electrical Network Frequency (ENF) Criterion. A case of a digital recording

One of the new methods of investigating the authenticity of evidential digital audio recordings uses the Electrical Network Frequency (ENF) Criterion. It is based on analysing the signal corresponding to the fundamental frequency of the current in the electrical network, which is present in a recording and comparing it with appropriate, reliable reference. Studies carried out at the Institute of Forensic Research in Cracow were aimed at validating this method, that is, assessing its usefulness in forensic examinations of evidential digital recordings in Poland. These studies enabled us to develop and implement a procedure for using the ENF Criterion method to assess the integrity of digital recordings and to establish when these recordings were made.     

The Average Direct Current Offset Values for Small Digital Audio Recorders in an Acoustically Consistent Environment

In this research project, nine small digital audio recorders were tested using five sets of 30‐min recordings at all available recording modes, with consistent audio material, identical source and microphone locations, and identical acoustic environments. The averaged direct current (DC) offset values and standard deviations were measured for 30‐sec and 1‐, 2‐, 3‐, 6‐, 10‐, 15‐, and 30‐min segments. The research found an inverse association between segment lengths and the standard deviation values and that lengths beyond 30 min may not meaningfully reduce the standard deviation values. This research supports previous studies indicating that measured averaged DC offsets should only be used for exclusionary purposes in authenticity analyses and exhibit consistent values when the general acoustic environment and microphone/recorder configurations were held constant. Measured average DC offset values from exemplar recorders may not be directly comparable to those of submitted digital audio recordings without exactly duplicating the acoustic environment and microphone/recorder configurations.     

Data fragment forensics for embedded DVR systems

A recent increase in the prevalence of embedded systems has led them to become a primary target of digital forensic investigations. Embedded systems with DVR (Digital Video Recorder) capabilities are able to generate multimedia (video/audio) data, and can act as vital pieces of evidence in the field of digital forensics.To counter anti-forensics, it is necessary to derive systematic forensic techniques that can be used on data fragments in unused (unallocated) areas of files or images. Specifically, the techniques should extract meaningful information from various types of data fragments, such as non-sequential fragmentation and missing fragments overwritten by other data.This paper proposes a new digital forensic system for use on video data fragments related to DVRs. We demonstrate in detail special techniques for the classification, reassembly, and extraction of video data fragments, and introduce an integrated framework for data fragment forensics based on techniques described in this paper.     

人牙咬痕同一认定数字化分析的盲法评定

目的评定人牙咬痕同一认定数字化分析方法的精确性。方法 采用数字化分析法对人牙咬痕及8名“疑犯”牙列模型进行双盲法分析实验,用Photoshop 5.5将获得的咬痕扫描图像生成overlay,用AutoCAD Rl4工程测量软件分析各项参数,比较人牙咬痕和“疑犯”牙列参数的匹配性。结果人牙咬痕及“疑犯”牙列模型数据化分析的各项参数分析结果一致。结论对于试验性咬痕,数字化分析是一种可行的认定方法,对法医学实践具有可行性及良好的应用前景。     

Passive forensics in image and video using noise features: A review

Due to present of enormous free image and video editing software on the Internet, tampering of digital images and videos have become very easy. Validating the integrity of images or videos and detecting any attempt of forgery without use of active forensic technique such as Digital Signature or Digital Watermark is a big challenge to researchers. Passive forensic techniques, unlike active techniques, do not need any preembeded information about the image or video. The proposed paper presents a comprehensive review of the recent developments in the field of digital image and video forensic using noise features. The previously existing methods of image and video forensics proved the importance of noises and encourage us for the study and perform extensive research in this field. Moreover, in this paper, forensic task cover mainly source identification and forgery detection in the image and video using noise features. Thus, various source identification and forgery detection methods using noise features are reviewed and compared in this paper for image and video. The overall objective of this paper is to give researchers a broad perspective on various aspects of image and video forensics using noise features. Conclusion part of this paper discusses about the importance of noise features and the challenges encountered by different image and video forensic method using noise features.