PDF Security & Access Issues

How to Add a Signature Certificate to Trusted Identities in Adobe Acrobat Pro

Kushani Nimanthika Oct 19, 2026 869 views

Question details

The user needs to add a digital signature certificate to their trusted identities list to successfully verify signed documents.

How to Add a Signature Certificate to Trusted Identities in Adobe Acrobat Pro

Product: Adobe Acrobat Pro
Device & OS: not provided
Scenario: Verifying the authenticity of digital signatures in a signed PDF document.
Observed behavior: The user wants to successfully import and trust a digital certificate to prevent 'Signature not verified' warnings.

Before you start

Ensure you have the sender's digital certificate file (usually in .cer, .crt, or .p7b format) saved on your local computer before attempting to add it to your trusted identities.

Solution 1Recommended

Adding Trusted Certificates in Adobe Acrobat Pro (Desktop)

Step-by-step guide to importing a digital certificate into Acrobat's trusted identities to validate document signatures.

By default, Adobe Acrobat validates signatures against a predefined list of trusted root certificates. If a document is signed with a self-signed certificate or one from an unrecognized authority, you must manually add it to your Trusted Identities.

Open Preferences

Open Adobe Acrobat Pro. Click on the 'Edit' menu (or 'Acrobat' on a Mac) and select 'Preferences'.

Access Signature Settings

Navigate to the 'Signatures' category in the left-hand pane. Under the 'Identities & Trusted Certificates' section, click the 'More' button.

Import the Certificate

Select 'Trusted Certificates' on the left side. Click the 'Import' button at the top, browse your computer, and select the certificate file you saved previously.

Trust the Certificate

Select the newly imported certificate from the list, click 'Trust', check the box to 'Use this certificate as a trusted root', and click 'OK' to save your changes.

Adding Trusted Certificates in Adobe Acrobat Pro (Desktop)

Signature Validation: Once the certificate is added and trusted, close the preferences window. Right-click the signature on your PDF document and select 'Validate Signature' to update its status.

Securely Sign and Verify PDFs with WPS Office

WPS PDF provides a seamless and cost-effective way to view, sign, and verify digital signatures in PDF documents. You can easily manage PDF security and ensure document authenticity without needing expensive PDF editors.

1. Open the PDF: Launch WPS Office and open your signed PDF document.
2. Navigate to the Protect Tab: Go to the 'Protect' tab on the top ribbon menu to access security and signature tools.
3. Manage Signatures: Click on 'Sign Document' to add your own digital signature, or use the signature pane to review existing signatures.
4. Validate Authenticity: Click on any existing digital signature in the document to validate its certificate, verify the signer's identity, and check the trust status.

Easily insert and verify digital signatures in PDF documents.Highly compatible with Adobe Acrobat PDF formats and security standards.Free, lightweight, and user-friendly interface.Comprehensive PDF editing, merging, and conversion tools.

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Frequently Asked Questions

Why does Acrobat say 'At least one signature has problems'?

This warning usually appears when the certificate used to sign the document is not in your list of trusted identities. Adding the sender's certificate to your trusted list will resolve the warning and validate the signature.

Can I add trusted certificates in Adobe Acrobat Reader (free version)?

Yes, you can add trusted certificates in the free Adobe Acrobat Reader by following a similar process in the Preferences > Signatures menu, allowing you to verify documents even without the Pro version.

What formats do signature certificate files use?

Digital signature certificates are commonly shared and imported using file extensions like .cer, .crt, .der, or .p7b. Ensure you obtain these files directly from a trusted source or the original signer.

How do I export my own certificate to send to someone else?

In Acrobat, go to Preferences > Signatures > Identities & Trusted Certificates > More. Select your Digital ID, click 'Export', and save the file to share with others so they can manually trust your signature on their devices.

PDF Troubleshooting