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How to Identify and Validate Non-Certified Digital Signatures in PDFs
Question details
The user wants to know if and how non-certified digital signatures can be identified and validated within a PDF application.
- Product
- PDF Reader Applications
- Device & OS
- Windows or Mac
- Scenario
- Receiving a digitally signed PDF document and needing to verify the signer's identity and ensure the document has not been tampered with.
- Observed behavior
- The user needs to view the signature's digital ID certificate status to confirm whether the signature is certified or non-certified, and check the document's overall integrity.
Ensure you have a reliable PDF reader installed on your Windows or Mac device and that you have an active internet connection if the application needs to check certificate trust lists online.
Validate Digital Signatures in Your PDF Reader
Check the signature properties manually to verify the authenticity of the digital ID certificate and confirm document integrity.
When you receive a signed document, signature validation determines whether the digital ID certificate is authentic and if the document content has been modified since it was signed. Many PDF applications allow automatic or manual validation depending on your security settings.
Launch your preferred PDF reader (such as WPS Office or Acrobat Reader) and open the document containing the digital signature.
Click on the digital signature directly within the document pages, or open the 'Signatures' panel usually found on the left sidebar of the application.
Right-click the signature and select 'Signature Properties' or 'Validate Signature'. The application will display the validity status, indicating if the signature is valid, non-certified, or invalid.
Click on 'Show Signer's Certificate' to view detailed information about the digital ID. This confirms the source of the signature and ensures the document's integrity remains intact.
Easily Validate Digital Signatures in PDFs using WPS Office
WPS Office provides a comprehensive PDF toolkit that allows you to easily view, manage, and validate digital signatures. Verify document integrity and signer identity with a secure, user-friendly interface.
- 1. Open the PDF in WPS Office: Launch WPS Office and open your digitally signed PDF document.
- 2. Access the signature: Navigate to the signature field within the PDF document or open the signature pane on the left menu.
- 3. Validate the digital ID: Click on the signature to instantly check the certificate status, review signer information, and confirm document integrity.
Frequently Asked Questions
What is the difference between a certified and a non-certified digital signature?
A certified signature is created using a digital ID from a trusted certificate authority (CA) and often restricts document modifications. A non-certified (or self-signed) signature might not have third-party trust verification, meaning you must manually verify the signer's identity.
Why does my PDF signature show as 'Unknown' or 'Invalid'?
This typically happens if the signer's certificate is not in your local list of trusted identities, or if the document was altered after the signature was applied. You may need to manually add the certificate to your trusted contacts if you recognize and trust the sender.
Can I validate PDF digital signatures on a Mac?
Yes. You can validate digital signatures on a Mac using compatible PDF software, such as WPS Office for Mac or Acrobat Reader. Simply click on the signature field within the document to view its certificate properties and validation status.
How do I make my PDF app validate signatures automatically?
In most standard PDF readers, you can go to the software's Preferences or Settings menu, find the 'Signatures' or 'Security' section, and check the option to 'Verify signatures when the document is opened'.
