Signed, Sealed, Altered? Deepdive into PDF Tampering

This blog outlines how to detect and analyze tampered PDFs, focusing on validating digital signatures in Adobe Acrobat, recovering prior versions, and uncovering hidden or overlayed content via annotations and extracted images using tools like Adobe Acrobat Pro, PDF-Processing, and pdfimages; it cautions that metadata alone is unreliable, highlights limitations when PDFs are unsigned or lack version history, and recommends using digital signatures, restricting edits, password protection, and source verification to ensure document integrity.