How do I know if a digital signature is valid?

Open the PDF in Acrobat. Click on the digital signature. Choose 'Validate Signature' in the panel. Acrobat will show if it's valid and who signed it.

What is the difference between a scanned signature and a digital signature?

Feature Scanned Signature Digital Signature. Appearance Image of a handwritten signature Electronic data, often with an icon Security Easy to copy or fake Hard to fake, linked to identity Validation Cannot be verified electronically Can be verified for authenticity and integrity

If my digital signature is not valid, what should I do?

Check the error message from Acrobat; it usually explains why. Verify the signer's certificate information. Manage your trusted identities to add or remove trust for certificate issuers. Contact the signer to ask for a new, valid signature if needed.

Verify Scanned Facsimile in Adobe Acrobat — How-to & AI prompts

AI prompts

1 way to ask · copy any one

CDecide — “help me choose”We received a scanned proof from the remote printer and I have to confirm in an hour that…+

We received a scanned proof from the remote printer and I have to confirm in an hour that folios, running heads, and the approved lead photo are correct. I can't be certain the scanned file hasn't lost a caption or swapped an image. Walk me through a fast but foolproof checklist to compare the scan to our master, including exact spots where printers typically introduce errors, and tell me what to stop the run for.

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 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.

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.

Long-Term Validation (LTV)Extra information added to a digital signature so it stays valid even if its certificate expires later.ExampleThe LTV information confirmed the signature was valid even though the original certificate expired.

The real tasks

the one, listed here

A scanned facsimile arrived and production asks me to verify it matches the intended layout before print.

FAQ

about this task

Open the PDF in Acrobat.
Click on the digital signature.
Choose 'Validate Signature' in the panel.
Acrobat will show if it's valid and who signed it.

Feature	Scanned Signature	Digital Signature
Appearance	Image of a handwritten signature	Electronic data, often with an icon
Security	Easy to copy or fake	Hard to fake, linked to identity
Validation	Cannot be verified electronically	Can be verified for authenticity and integrity

A digital signature's validity relies on trust because it uses a certificate. This certificate confirms the signer's identity. If you trust the company or organization that issued the certificate, you can trust the signature. Acrobat helps you manage these trusted identities.

Check the error message from Acrobat; it usually explains why.
Verify the signer's certificate information.
Manage your trusted identities to add or remove trust for certificate issuers.
Contact the signer to ask for a new, valid signature if needed.

Long-Term Validation (LTV) is important because it ensures a digital signature remains valid even after the original signing certificate expires. Without LTV, a signature might become invalid over time, making it hard to prove the document's authenticity years later. LTV adds extra information to the signature, like a timestamp, to preserve its validity for the future.

Verify Scanned Facsimile

When to use it

AI prompts

How to do it

Glossary

The real tasks

Who does this

FAQ

Sources

Adobe help