How do I know if a digital signature in my document is valid?

Open your PDF document in Adobe Acrobat. Click on the 'Signatures' panel on the left side. Right-click on the specific digital signature you want to check. Select 'Validate Signature' from the menu to see its status.

What is a trusted identity and why does it matter for digital signatures?

A trusted identity refers to a digital certificate that you have chosen to trust in Adobe Acrobat. It matters because Acrobat uses this trust to decide if a digital signature is valid. If you trust the certificate of the person who signed the document, Acrobat can confirm their identity and that the document has not been changed since they signed it. Managing trusted identities helps you control who you believe is authentic.

If a digital signature says 'valid but with warnings', what should I do?

First, check the warning details. It might be about the certificate's trust or a timestamp issue. Next, try to verify the certificate information. Make sure it comes from a known and reliable source. Consider adding the signer's certificate to your list of trusted identities if you know and trust them. If the warning is about long-term validity, add LTV information to make the signature self-validating over time.

Why is it important to add Long Term Validation (LTV) information to a digital signature?

Adding Long Term Validation (LTV) information to a digital signature is important because it helps the signature stay valid far into the future. Without LTV, a signature might become invalid if the signer's certificate expires or is revoked. LTV embeds all the necessary information, like timestamps and revocation status, directly into the PDF, making the signature self-validating over a long period, even without external checks.

What is the difference between verifying a signature and managing trusted identities?

Action Purpose Outcome. Verifying a signature To check if a specific digital signature on a document is valid, who signed it, and if its certificate is trusted at that moment. You get an immediate status report on the signature's validity and integrity. Managing trusted identities To tell Adobe Acrobat which digital certificates you personally trust, so it can use this information for future signature validations. You build a list of trusted signers, making future signature verifications smoother and more reliable based on your preferences.

Validate signatures on certified PDFs in Adobe Acrobat — How-to & AI prompts

AI prompts

3 ways to ask · copy any one

AExecute — “help me do it”Check if the signature on [PDF file] is valid and official.…+

Please check if the signature on [PDF file] is valid and official. Tell me if it is trusted or not.

when the reply comes backWould you like to learn how to add your own signature?

BImprove — “do it better”Show me more about the signature on [PDF file], like who signed it...…+

Show me more about the signature on [PDF file], like who signed it, when, and if anything changed after signing.

when the reply comes backNeed help fixing an invalid signature on your PDF?

CDecide — “help me choose”Help me choose which of these two PDFs has a valid signature...…+

Help me choose which of these two PDFs has a valid signature: [PDF file 1] and [PDF file 2]. Tell me which one is more trustworthy.

when the reply comes backWant to know how to spot fake digital signatures?

How to do it

the tool · the steps · what to avoid

1
Open the PDF document containing the digital signature you want to validate.
2
Locate the signature field or signature panel in the document.
3
Click directly on the digital signature or open the signature panel and select the signature you wish to validate.
4
In the signature details popup, click Signature Properties.
5
In the Signature Properties dialog, click Show Certificate to review certificate details if needed.
6
Close the certificate window, then click Validate Signature in the Signature Properties dialog.
Best practiceIf the signature status shows as 'Unknown' or 'Not Valid', check if the signer's certificate needs to be added to your list of trusted identities.
7
Review the validation result displayed in the Signature Properties dialog.

In the appWith the API

You can view detailed information about the signature's validity and certificate by clicking on the signature and opening Signature Properties.

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

Glossary

words on this page

Certified PDFA PDF that has a certificate signature showing it is official and safe.ExampleThe Certified PDF of the contract showed a badge confirming it was official and unchanged.

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.

ValidationChecking if something is real or still works as it should.ExampleThe software performs a validation check to ensure all required fields in the form are filled out correctly.

The real tasks

the one, listed here

Finance asked for an audit trail today and I need to confirm every agreement has auditable timestamps.

FAQ

about this task

Open the PDF in Adobe Acrobat, look for the signature panel, and check if the signature is marked as valid. Acrobat will show a message if the signature is trusted or not.

If a signature is 'not valid', it could mean the document was changed after signing, the signer is not trusted, or the signature is damaged. Always check the details to understand the reason.

Validating signatures helps you make sure the document is real and hasn't been changed. This is important for legal, school, or work documents.

Some other PDF readers can check signatures, but Adobe Acrobat is the most reliable for this task. Always use trusted software to check important documents.

A digital signature uses special technology to prove who signed and if the file was changed, while a scanned signature is just an image and can't be checked for security.

Validate signatures on certified PDFs

When to use it

AI prompts

How to do it

Glossary

The real tasks

Who does this

FAQ

Sources

Adobe help