Forensic authenticity examination of PDF documents

With the rapid development and widespread popularization of information technology, Portable Document Format (PDF) documents have gradually become a type of digital files that are easily accessible and closely related to the public. In digital forensics, digital files in the form of PDF documents are often encountered, and their authenticity needs to be determined. Therefore, the research on its key forensic techniques has important theoretical research significance and practical application value. However, through searching the literature, we can find that there is still a lack of systematic research on forensic authentication of PDF documents. Based on the above situation, this paper first studies the file structure and digital composition of PDF documents; The digital data characteristics and the contents for examination of PDF files produced by the mainstream scenarios are studied, including PDF generated by scanners, converting directly from images, and transforming from DOCX documents, etc. Finally, a case study is carried out to explain the key technologies and examination contents for authenticity examinations of PDF documents in detail. Our study will provide theoretical basis and practical guidance for forensic investigations of authenticity examinations of PDF documents.