Verify PDF Print Authenticity

TL;DR

Printing a Word document to PDF doesn’t automatically guarantee its authenticity. This guide explains how to check if a PDF has been altered after printing, focusing on digital signatures and metadata verification.

Checking PDF Authenticity After Printing

1. Understand the Limitations: Simply printing a Word document to PDF doesn’t create a tamper-proof record. Anyone can modify a PDF. True authenticity requires additional steps *before* printing.
   • Printing converts the document into an image or vector format, losing some original data.
   • Metadata can be easily altered without leaving obvious traces.
2. Check for Digital Signatures: This is the most reliable method if a signature was applied *before* printing.
   1. Open the PDF in Adobe Acrobat Reader (or similar): Don’t use just any PDF viewer; you need one that supports signature validation.
   2. Look for Signature Panel: Go to Edit > Digital Signatures or a dedicated ‘Signatures’ panel.
   3. Validate the Signature: Acrobat will attempt to verify the signature against the certificate authority.
      • Valid Signature: Indicates the document hasn’t been altered since signing. You’ll see details about the signer and validity period.
      • Invalid Signature: Means the document has been changed, or the certificate is invalid/expired. Acrobat will usually provide a reason.
      • No Signature Detected: The document wasn’t signed before printing.
3. Examine PDF Metadata: This provides information about the document’s creation and modification history, but is less reliable than digital signatures.
   1. Open PDF Properties: In Acrobat Reader, go to File > Properties.
   2. Review ‘Description’ Tab: Look at fields like:
      • Creator: Who created the original document?
      • Producer: Which application was used to create the PDF (e.g., Microsoft Word)?
      • Creation Date: When was the PDF initially created?
      • Modification Date: When was the PDF last changed? Be wary of recent modification dates if you expect an older document.
   3. Check ‘Security’ Tab: See what security features are enabled (or disabled). If restrictions have been removed, it suggests tampering.
4. Inspect Hidden Data (Advanced): Some PDF editors allow viewing of hidden layers or objects. This requires more technical expertise.
   1. Use a PDF Editor: Adobe Acrobat Pro is the most common option, but others exist.
   2. Examine Layers/Objects: Look for unexpected content that might have been added after printing.
      • This can reveal hidden text or images.
5. Compare with the Original Word Document (If Available): This is a manual process but can highlight discrepancies.
   1. Open both documents side-by-side: Carefully compare text, formatting, images, and tables.
   2. Look for subtle changes: Pay attention to font differences, spacing issues, or missing elements.
6. Consider PDF/A Format (For Archiving): If long-term preservation of authenticity is crucial, convert the Word document to PDF/A *before* printing.

   PDF/A is an ISO standard designed for archiving. It embeds all necessary fonts and information to ensure consistent rendering over time.

   pdftk input.docx output output.pdfa compatibility 1.7