How to Verify Who Signed or Modified a PDF Document
Question details
The user wants to know if a PDF digital signature can identify the exact person who applied it (such as distinguishing between a manager and their assistant) and if PDF files can track specific document edits.
- Product
- Device & OS
- not provided
- Scenario
- Verifying document authenticity, confirming the physical identity of the signer, and reviewing the document's modification history.
- Observed behavior
- PDF files do not have a native Track Changes feature like Microsoft Word. Additionally, digital signatures authenticate the certificate used, but cannot prove who physically used the signing credentials.
Ensure you have the original signed PDF file and a reliable PDF viewer capable of displaying digital signature properties and certificate details.
Understand Digital Signature Identity Limitations
Use this information to correctly interpret what a digital signature verifies regarding the signer's identity.
A digital signature cryptographically binds a document to a specific digital certificate. It confirms that the document was signed using a particular set of credentials and that the file has not been tampered with since the signature was applied.
However, a digital signature does not verify the physical identity of the person sitting at the computer. If an assistant has access to and uses a manager's digital signature credentials, the signature alone cannot distinguish who actually performed the action.
Open your PDF document in a PDF viewer and click on the 'Signatures' panel, usually located on the left sidebar.
Right-click the signature in the document or the panel and select 'Show Signature Properties' or 'Certificate Details' to see whose digital ID was used.
Compare PDF Versions to Identify Modifications
Since PDFs lack a native 'Track Changes' feature, you must compare the modified file against the original version to see what changed.
View Signatures and Compare Documents with WPS Office
WPS PDF offers a comprehensive suite of tools to easily view digital signature validity, inspect certificate details, and compare multiple versions of your PDF documents to spot modifications.
- 1. Open the PDF document: Launch WPS Office and open your digitally signed PDF file.
- 2. Inspect the signature: Click directly on the signature field within the document to view the signature validation status and detailed certificate information.
- 3. Compare versions: If you suspect unauthorized edits, use the 'Compare' tool in the PDF toolkit to load the original and modified documents side-by-side to highlight any changes.
Frequently Asked Questions
Does a PDF save a history of who edited it?
No, standard PDF files do not maintain an automatic version history or 'Track Changes' log like Word documents. You can only see the current author in the document properties, unless a specialized document management system was used.
How can I ensure no one modifies my PDF after signing?
When applying a digital signature, you can check the option to 'Lock Document After Signing'. This secures the file, and any subsequent modifications will immediately invalidate the digital signature, alerting future readers to the tampering.
Can I track changes in a PDF if I convert it to Word?
Yes. By converting a PDF to a Word document using a tool like WPS Office, you can enable 'Track Changes' in the word processor to monitor and log any future edits made by collaborators.
What is the difference between an electronic signature and a digital signature?
An electronic signature is typically a visual representation of your handwritten signature, like an image or drawing. A digital signature is highly secure, using a cryptographic certificate to verify the document's authenticity and ensure the file hasn't been modified.
