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 a digital signature on a PDF in Adobe Acrobat — How-to & AI prompts

AI prompts

3 ways to ask · copy any one

AExecute — “help me do it”Please help me check if the signature on...…+

Please help me check if the digital signature on [this PDF file] is valid and trusted.

when the reply comes backWant to learn how to add your own digital signature?

BImprove — “do it better”Can you explain what the signature details mean...…+

Can you explain what the digital signature details mean in [this PDF] and how to spot problems?

when the reply comes backNeed help understanding what a signature error means?

CDecide — “help me choose”Should I trust the digital signature on...…+

Should I trust the digital signature on [this PDF]? What should I look for before accepting it?

when the reply comes backLooking for ways 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

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.

ValidateTo check if something is real or correct.ExampleThe system validates your login details to confirm you are an authorized user.

PDFA common file type used to share documents that look the same everywhere.ExampleShe saved the brochure as a PDF so everyone would see the exact same layout and fonts.

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

To validate a digital signature in Adobe Acrobat, open the PDF and click on the signature. Acrobat will show if the signature is valid, who signed it, and if it has been changed since signing.

A 'valid' digital signature means the document has not been changed after signing, and the signer’s identity can be trusted based on their certificate.

Validating digital signatures helps you make sure the document is real, hasn't been changed, and was signed by the right person.

Some other PDF readers can check digital signatures, but Adobe Acrobat is the most common and reliable for this task.

If a signature is not valid, you should check with the sender to make sure the document is correct and has not been changed by someone else.

Validate a digital signature on a PDF

When to use it

AI prompts

How to do it

Glossary

The real tasks

Who does this

FAQ

Sources

Adobe help