Verifying a signature checks the signature’s validation and whether any changes have been made to the document since it was signed. If the signer’s certificate, or one of its parent certificates, is not on your list of trusted identities, it will be listed as “Unknown.”

To verify a signature:

  1. Open a PDF document containing a digital signature.
  2. Check whether the Warning Sign icon appears next to the signature. If it does, the document may have been modified after it was signed.
  3. Right-click a signature on the page and then select Verify Signature from the menu.
  4. Click Properties to learn more information about the signature. If the status is unknown, you will have to verify the signature by contacting the signer. Click Verify Identity to see if the user has left contact information. If so, you can confirm the signature’s origin by matching certificate numbers. If there is no contact information but you know the individual directly or indirectly, use alternate means to reach them.


Verifying a Signature