How do I validate a digital signature in a PDF document?

Open the PDF with the signature in Acrobat. Click on the digital signature. Select 'Validate Signature' from the options that appear. Acrobat will show you the signature's status and details.

If my digital signature shows as 'unknown validity', what should I do?

Check the signer's certificate details to see who signed it. You might need to add the signer's certificate to your list of trusted identities in Acrobat. Contact the signer to get their certificate if you don't have it.

What is the difference between a 'valid' and a 'trusted' digital signature?

Feature Valid Digital Signature Trusted Digital Signature. Meaning The signature is technically correct and the document has not been changed since signing. The signer's certificate is recognized and accepted as reliable by your Acrobat settings. Requirement Relies on the signature's cryptographic data and timestamp. Relies on your trust relationship with the signer's certificate or its issuer. Action Needed Acrobat checks this automatically when you validate. You might need to manually add the signer's certificate to your trusted identities. Outcome Confirms document integrity. Confirms signer's identity and reliability, providing higher assurance.

Speed Legal Signoff Trust in Adobe Acrobat — How-to & AI prompts

AI prompts

1 way to ask · copy any one

CDecide — “help me choose”We have revised policy training that legal needs to approve and they keep requesting version…+

We have revised policy training that legal needs to approve and they keep requesting version comparisons. Assemble the revised materials with visible change history and a short briefing that highlights only the legal-impact changes. Explain which changes are likely to trigger legal questions and propose one packaging approach that will get a faster sign-off from legal.

when the reply comes backPush once: ask it to sharpen the weakest part, and to say what it assumed.

How to do it

the tool · the steps · what to avoid

1
Open the signed PDF document in Adobe Acrobat.
2
Open the Signatures panel from the navigation pane.
3
Right-click the signature you want to validate and select Validate Signature.
4
In the signature validation status dialog, review the signature details and validation status.
5
Click Show Certificate to review certificate details and ensure it matches the required legal or industry standard (e.g., eIDAS, FDA 21 CFR Part 11).
CautionYou must know your organization's required certificate authorities and validation criteria for compliance.
6
Review the signature properties panel for compliance details specific to regulatory standards.
NoteThis option appears only if the signature contains compliance information.
7
Check the validation summary for explicit compliance statements or error messages regarding legal or industry standards.
8
If the signature is not compliant, consult your organization's digital signature policy or contact your certificate provider for remediation.
Best practiceSome enterprise workflows require importing trusted root certificates into Acrobat's trusted identities list to validate signatures against specific regulations.

In the appWith the API

You can configure trusted identities in Acrobat to ensure signatures are validated against your organization's compliance requirements.

This runs in the Acrobat app - there is no separate API for this task.

Glossary

words on this page

Digital SignatureAn electronic mark on a document that proves who signed it and that the document has not changed.ExampleA digital signature on your tax return confirms you submitted it and that its contents are unchanged.

CertificateAn electronic file that proves a person's or organization's identity online, like a digital ID card.ExampleYour certificate confirms your identity when you access secure online government services.

Trusted IdentitySomeone whose digital signature certificate you have chosen to trust in your software.ExampleYou add your manager's digital signature certificate as a trusted identity in your document software.

The real tasks

the one, listed here

Legal takes too long to sign off on revised policy training; I want approvals faster without losing their trust.

FAQ

about this task

Open the PDF with the signature in Acrobat.
Click on the digital signature.
Select 'Validate Signature' from the options that appear.
Acrobat will show you the signature's status and details.

When a digital signature is 'trusted', it means Adobe Acrobat recognizes the certificate used to sign the document as coming from a reliable source or someone you have chosen to trust. This trust helps confirm that the signature is authentic and that the document has not been altered since it was signed. Without trust, even a valid signature might not be considered reliable.

Check the signer's certificate details to see who signed it.
You might need to add the signer's certificate to your list of trusted identities in Acrobat.
Contact the signer to get their certificate if you don't have it.

Verifying certificate information is important because it confirms the identity of the person or organization that signed the document. The certificate acts like a digital ID. By checking it, you can be sure the signature truly belongs to the claimed signer and that their identity has been verified by a trusted third party. This adds a strong layer of security and legal confidence to the document.

Feature	Valid Digital Signature	Trusted Digital Signature
Meaning	The signature is technically correct and the document has not been changed since signing.	The signer's certificate is recognized and accepted as reliable by your Acrobat settings.
Requirement	Relies on the signature's cryptographic data and timestamp.	Relies on your trust relationship with the signer's certificate or its issuer.
Action Needed	Acrobat checks this automatically when you validate.	You might need to manually add the signer's certificate to your trusted identities.
Outcome	Confirms document integrity.	Confirms signer's identity and reliability, providing higher assurance.

Speed Legal Signoff Trust

When to use it

AI prompts

How to do it

Glossary

The real tasks

Who does this

FAQ

Sources

Adobe help