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If you are unsure whether a signature within a PDF is valid, you can verify it yourself. This article will guide you through the process on how to validate signature in PDF, utilizing tools such as MiniTool PDF Editor and Adobe Acrobat.

In daily work, contracts, invoices, and other important PDF files will contain digital signatures to ensure authenticity.

How to verify the authenticity of a signature and determine whether the document has been tampered with? The specific verification methods are outlined below.

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Why Do You Need to Validate Signature

Verifying signatures is of paramount importance. It confirms the identity of the signer, ensures that the document has not been altered since it was signed, etc.

The following are the reasons why signature verification is essential:

  1. Verify document integrity: Validating a signature confirms that the PDF has not been altered since it was signed. Even the slightest modification to the document will render the signature invalid.
  2. Verify signer identity: Digital signatures are typically linked to information such as an email address. By validating the signature, it is possible to confirm whether it was created by a specific individual. This process helps prevent forgery.
  3. Provide legal validity: A validated signature acts as a reliable electronic seal, attesting to the authenticity of the document and endowing it with legal force.
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How to Validate Signature in PDF

How to verify digital signature in PDF? Common approaches include: MiniTool PDF Editor and Adobe Acrobat.

Method 1: MiniTool PDF Editor

MiniTool PDF Editor is a complete, all-in-one PDF tool that lets you validate signature in PDF.

It can also encrypt PDFs, add watermarks, stamps, lines, etc. Furthermore, it supports creating, editing, compressing, converting, splitting, or merging PDF files.

Note: MiniTool PDF Editor offers a 7-day free trial. Once the trial expires, access to many advanced features will be restricted. To continue using them, you must upgrade to the Pro edition.

Here are the detailed steps on how to verify signature in PDF via MiniTool PDF Editor:

Step 1: Download and install MiniTool PDF Editor on your computer. Then launch it to enter its main interface.

MiniTool PDF EditorClick to Download100%Clean & Safe

Step 2: Open a PDF file that you want to validate the signature with MiniTool PDF Editor.

Step 3: Under the Protect tab, click Manage Signature, then select Validate All Signature. In the new pop-up window, click Continue.

The MiniTool PDF Editor Protect interface with the selected Validate All Signature.

Step 4: In just a few seconds, MiniTool PDF Editor, can verify all your digital signatures. On the new interface, you can see whether your signatures are valid. Then, click OK to exit that interface.

The Validate All Signature interface with the selected OK option.

Further reading:

How is an invalid signature displayed in a PDF? If the signature is invalid, the following interface will be displayed.

The Validate All Signature interface with the signature is invalid.

Next, you can click Signature Properties to find out the specific reason why the signature is invalid. Three reasons are explained here:

  • The document has been modified or damaged since the signature was applied.
  • The signer’s identity is unknown.
  • The signing time relies on the signer’s computer clock.
The Signature Properties interface showing the reason that the signature is invalid.
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Method 2: Adobe Acrobat

Another method to validate signature in PDF is using Adobe Acrobat. It is a widely used and powerful PDF software that enables the efficient creation, viewing, editing, and management of PDF files.

In addition to basic PDF editing capabilities, it offers advanced tools for handling digital signatures. With Adobe Acrobat, you can check the validity of signatures, and more.

Detailed steps are provided below:

Step 1: Open Adobe Acrobat and click Open File to open the PDF containing the signature.

Step 2: In the new pop-up windows, find your digital signature, right-click it, and choose Validate Signature.

The Adobe Acrobat interface with the selected Validate Signature option.

Step 3: You will soon be notified whether your digital signature is valid. To learn more about digital signatures, click Signature Properties > Show Certificate option.

The Signature Validation Statue interface with the selected Signature Propertiesoption.

Step 4: In the Certificate Viewer option, you can learn more about the digital signature’s details.

Tips:
Navigate to the Trust tab and click Add to Trusted Certificates. This operation allows Acrobat to trust future signatures from this signer.
The Certificate Viewer interface to show more information about the signature.
Tips:
If you want to validate all signatures, you can click All tools from the Adobe global bar, then select Use a certificate > Validate all signatures. Finally, click OK. Once all signatures are verified, a confirmation text is displayed.

How to verify digital signature in PDF? This article introduces two methods to help you validate signature in PDF.Click to Tweet

Bonus Tip: What to Do If You Fail to Validate Signatures in PDFs

In some cases, you may be unable to verify signatures in a PDF file. The following provides some possible solutions:

  1. Check if the document has been modified: Once a signature has been generated, any subsequent changes to the document’s content will result in verification failure.
  2. Verify the certificate’s trustworthiness: If the signing certificate is not included in your list of trusted certificates, the system may be unable to validate the signature. Please try adding the signer’s certificate to your list of trusted certificates.
  3. Check the certificate’s validity period: Verification will also fail if the signing certificate has expired or has not yet become active.
  4. Update your PDF reader software: Older versions of the software may be unable to correctly validate newer types of digital signatures.
  5. Re-import or re-sign: If the methods above do not resolve the issue, please digitally sign the PDF document again.

Bottom Line

In conclusion, validating PDF signatures is essential for ensuring the authenticity and integrity of digital documents. Both MiniTool PDF Editor and Adobe Acrobat provide reliable ways to verify signatures efficiently.

If you have any questions or suggestions while using the MiniTool PDF Editor, you can contact us via [email protected] to get a quick reply.

About The Author

Cecilia
Cecilia

Position: Columnist

Cecilia is a new member of MiniTool. She works as an English editor on the MiniTool team. She likes to learn articles about computers and is passionate about partition management and Windows operating systems. She is committed to allowing readers to use simple, efficient, and fast methods to solve the computer problems they encounter. To provide more professional solutions, she will continue to learn and master computer knowledge.