Why is a digital signature not valid?

Asked by: Miss Joelle Johnson  |  Last update: March 10, 2026
Score: 4.9/5 (44 votes)

A digital signature becomes invalid primarily because the document was altered after signing, the signer's certificate expired or was revoked, the Certificate Authority (CA) isn't trusted, or there are technical issues like using unsupported algorithms or data corruption during transmission. It means the signature no longer accurately proves the signer's identity or that the content is unchanged.

Why is my digital signature not valid?

If a digital signature isn't valid, there can be many causes. For example, the sender's certificate may have expired, it may have been revoked by the certificate authority (CA), or the server that verifies the certificate might be unavailable. Notify the message sender of the problem.

Why does it say my e-signature is invalid?

Explanation. When opening a digitally signed PDF, Adobe may display a message indicating that ”At least one signature is invalid". This message typically appears when Adobe does not recognize the certificate authority that issued the digital certificate used to sign the document.

How to make a digital signature valid?

To digitally sign an Office document, you must have a current (not expired) digital certificate. Digital certificates are typically issued by a certificate authority (CA), which is a trusted third-party entity that issues digital certificates for use by other parties.

How do I fix an invalid signature on a PDF?

In Adobe Acrobat, navigate to All Tools > Use a Certificate > Digitally sign. Using your mouse, draw a rectangle where you want the digital signature to display in the document. Select the appropriate Document Signing Certificate in the Sign with a Digital ID window and hit Continue.

How To Fix This File Does Not Have A Valid Digital Signature That Verifies Its Publisher Windows

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Why is my digital signature not working on PDF?

Check the PDF security certificate.

Security features on the PDF file itself could block signing. You can check the security options with your PDF editing software. If you can't sign PDF, you may have to ask the author for an unlocked version.

How do I activate my digital signature?

On the Tools menu, click Form Options. Under Category, click Digital Signatures, and then click Enable digital signatures for specific data in the form. Click Add.

How to get a valid digital signature?

For creating electronic signatures, the signer is required to obtain a Digital Signature Certificate (DSC) from a Certifying Authority (CA) licensed by the Controller of Certifying Authorities (CCA) under the Information Technology (IT) Act, 2000.

What is required for an electronic signature to be valid?

While the requirements for an electronic signature to be legally valid can vary from country to country, or even within the United States, four common general principles abide that relate to intent, consent, (authentication), and proper record retention.

How do I make a document electronically signable?

Open a PDF file in Acrobat. Click the Fill & Sign tool in the right pane. Add a recipient: Enter an email address and add a custom message if you want. Then click “Next.”

How to make signature valid in PDF?

5 Steps for Validating Digital Signatures In a PDF

  1. Open the digitally signed PDF that you need to validate using Power PDF.
  2. Locate the digital signature object within the document.
  3. Right click or command-click on the signature object.
  4. Select "Verify Signature" from the context menu.

How do I enable electronic signature on a PDF?

How to Digitally Sign a PDF in Adobe Using a Document Signing Certificate

  1. Open your file in Adobe Acrobat. ...
  2. Select Tools in the top navigation bar. ...
  3. Under Certificates, press Open. ...
  4. Hit “Digitally Sign” to select where to place your signature. ...
  5. Choose the digital signature to sign with. ...
  6. Save your file as a new PDF.

How do I add a trusted certificate to a PDF?

Trusted Certificates

  1. Right-click the digital signature, and choose Show Signature Properties.
  2. In the Signature Properties dialog box, click Show Certificate.
  3. In the Certificate Viewer dialog box, specify the trust level for the certificate in the Trust tab: ...
  4. Click Add to Trusted Certificates, and confirm your operation.

How to verify if a digital signature is valid?

Right-click on the digital signature to bring up a drop-down menu. Here, you'll find Validate Signature listed as the top option. This Signature Validation Status allows you to verify whether the signature is valid, if the document has been tampered with, and whether the signer's ID is valid.

How to unlock digital signature in PDF?

How it works

  1. Download a new copy of the PDF (with the new sealer password applied)
  2. Open the PDF.
  3. Click the 'Lock' icon in the upper-left corner of the page.
  4. Click the link labeled: Permission Details.
  5. In the "Security Method' drop down, select: No Security.
  6. Enter your unlock password and click the OK button three times.

How to create a digital signature?

To create a digital signature, use an online generator (like Canva, DocuSign, Adobe) to draw, type, or upload your signature, or create one from a physical signature by drawing on paper, scanning/photographing it, and cleaning the image in a photo editor as a PNG file. Then, apply it to documents within apps like Microsoft Word or PDF editors (Adobe Acrobat) for electronic signing, or use a dedicated e-signature service for more secure, legally binding digital certificates.
 

Can I just type my name for an electronic signature?

Using a typed signature in your business is legal and accepted. But for an esignature that is legally binding and valid, you must adhere to the following rules: Prove that the signer wanted to sign by providing options like “Cancel.” Prove that the signer wanted to carry out their business electronically.

Which documents are required for a digital signature?

Identity Proof

  • Aadhar Card.
  • Passport.
  • PAN Card.
  • Driving Licence.
  • Post Office ID Card.
  • Bank Account Passbook containing the photograph and signed by an individual with attestation by the concerned Bank official.
  • Any Government-issued photo ID card bearing the signatures of the individual.

What does a valid e-signature look like?

One of the symbols to indicate an electronic signature is /s/, placed before the signer's name. For example, /s/ Jimmy Doe. The other symbol is the signer's name between two forward slashes, typed out, for example, as /Jimmy Doe/.

What is considered a valid digital signature?

Authenticity The signer is confirmed as the signer. Integrity The content has not been changed or tampered with since it was digitally signed. Non-repudiation Proves to all parties the origin of the signed content. Repudiation refers to the act of a signer denying any association with the signed content.

How do I convert a jpeg to a digital signature?

Online PNG Maker

Just import a photo or a scan of your signature in the JPG format in the editor on the left, select the background color, and you'll instantly get a signature in the PNG format without the background on the right. Free, quick, and very powerful. Created with love by team Browserling.

Does a PDF have a digital signature?

Add your PDF signature fast

To sign PDF forms, create an electronic signature for free and then place it or your initials anywhere in the PDF document. You can type, draw, or upload an image of your signature.

What to do if a digital signature is not working?

Solution- Restart your device and try again or update your software or app to the latest version to fix technical issues. Expired Certificate- A Digital signature for individuals has expiration dates. If your certificate is expired, it will only work once you renew it.

What is the difference between digital signature and electronic signature?

A digital signature is always electronic, but an electronic signature is not always digital. A digital signature works with encryption technology using a cryptographic mechanism that provides additional security for the document and guarantees its integrity.

Why is my PDF not allowing digital signature?

Password protection or file permissions sometimes restrict document signing capabilities. Trying to sign locked files triggers “Why does Adobe Reader not let me sign this PDF file?” errors. Diagnose restrictions: Check a PDF's File > Properties > Security settings.