Difference Between Certifying and Digitally Signing a PDF Document
Question details
The user wants to understand the distinction between applying a certifying signature and a standard digital (approval) signature to a PDF document.
- Product
- Device & OS
- not provided
- Scenario
- Securing, authenticating, and restricting permissions on official PDF documents using certificate-based digital signatures.
- Observed behavior
- Users need to know the proper sequence for applying these signatures and the specific document restrictions that each signature type imposes.
Ensure you have a valid digital ID or certificate installed on your system or provided by a trusted Certificate Authority (CA) before attempting to certify or sign a document.
Understand the Core Differences and Use Cases
Learn the primary functions of certifying signatures versus approval signatures to determine which one is appropriate for your document stage.
While both are certificate-based digital signatures, they serve entirely different purposes in a document's lifecycle. A certifying signature acts as the foundational security layer, whereas approval signatures are used to gather individual consent.
A certifying signature must be applied first, before any other signatures are added. It establishes the document's initial integrity and allows the creator to restrict what subsequent operations (like filling forms or adding comments) are permitted without invalidating the document.
An approval signature (often just called a digital signature) is applied after a document is created or certified. It identifies a specific person who has reviewed and approved the document's contents.
Understand that a certifying signature can be visible or invisible; many official government documents use invisible certification. Ordinary approval signatures are typically visible and placed in specific signature blocks within the PDF.
Check the Certification Status of a Received PDF
Verify whether a PDF you have received has been certified or merely digitally signed by inspecting its security properties.
Easily Digitally Sign and Secure PDFs with WPS Office
WPS Office provides a comprehensive suite of PDF tools, allowing you to seamlessly add, view, and validate digital signatures to ensure document authenticity and integrity.
- 1. Open your PDF: Launch WPS Office and open the PDF document you need to sign.
- 2. Navigate to the Protect Tab: Click on the 'Protect' tab located on the top ribbon menu to access security features.
- 3. Add a Digital Signature: Click on 'Digital Signature' or 'Sign Document', and select your preferred digital ID or certificate from your system.
- 4. Save to Apply: Place the signature on the document and save the file to lock in your digital signature.
Frequently Asked Questions
Can I add an approval signature to a PDF that is already certified?
Yes, provided the person who applied the certifying signature configured the document permissions to allow additional form filling or approval signatures. If they restricted all changes, adding an approval signature will invalidate the document.
Does certifying a PDF prevent all edits?
It depends on the certifier's settings. When certifying a document, the author can choose to disallow any changes, allow only form filling and signing, or allow annotations, form filling, and signing.
How do I obtain a digital ID to certify a document?
You can either create a self-signed digital ID directly within your PDF software for internal use, or purchase a verified certificate from a trusted third-party Certificate Authority (CA) if you need the signature to be automatically trusted on devices outside your organization.
Why is my digital signature showing as invalid?
A signature typically shows as invalid if the document's content was altered after the signature was applied, or if the digital certificate used to sign the document is expired or not trusted by your device's operating system.
