苹果手机录制录音的真实性鉴定若干问题探究

Research on Some Problems of Forensic Authentication of Audio Recordings Recorded by iPhone

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。

In order to explain the various doubts found in the case of forensic authentication of audio recordings recorded by iPhone,this paper makes a series of experimental analysis and exploration by using the iPhone in the case and some other common iPhones.In this experiment,the recording fi les of iPhone12,iPhone SE,iPhone 6 and iPhone 4s were synchronized,copied,cut,replaced,cleaned,and the recording quality was modifi ed,and the changes of fi le name format,sampling rate,modifi cation date and“composition”fi le folder were observed.The experiment found that in the experimental iPhones,the recording fi le of the voice memo was only allowed to be synchronized once.The“Lossless audio”and“Compressed audio”settings in iPhone recording settings only changed the voice frequency and did not change the recording sampling rate.The experiment summarized the fi le name changing rules of copying voice from the above-mentioned iPhone voice memo recording list,and found that cutting and replacing operations did not change the fi le name format.In the experiment,the sampling rate changed only when the iPhone 12 recorded audio was replaced,and this phenomenon did not occur in other experimental operations or experiments on other iphones.The original recordings recorded on iPhones were stored in the“composition”folder,but when copying,only voice fi les existed on the phone,and there was no“composition”folder.The existence and content of the“Fragments”folder in the“composition”folder were related to the model of iPhones and the specifi c operation behavior of recording fi les.Therefore,the“composition”folder and the“fragment”folder could become the key inspection items for the authenticity identifi cation of the recorded fi les on iphones.ITunes voice memo information had strong stability and would not change with fi le copying and editing.These regular understandings can provide theoretical basis and practical experience for the forensic audio authentication of more recordings recorded by iPhones.