Research on Some Problems of Forensic Authentication of Audio Recordings Recorded by iPhone
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 files of iPhone12,iPhone SE,iPhone 6 and iPhone 4s were synchronized,copied,cut,replaced,cleaned,and the recording quality was modified,and the changes of file name format,sampling rate,modification date and"composition"file folder were observed.The experiment found that in the experimental iPhones,the recording file 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 file 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 file 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 files 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 specific operation behavior of recording files.Therefore,the"composition"folder and the"fragment"folder could become the key inspection items for the authenticity identification of the recorded files on iphones.ITunes voice memo information had strong stability and would not change with file copying and editing.These regular understandings can provide theoretical basis and practical experience for the forensic audio authentication of more recordings recorded by iPhones.
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