Digital signature validation helps you verify the authenticity of the signature’s digital ID certificate status and document integrity. The validity of signatures depends on whether the signer’s certificate exists in the validator’s list of trusted identities (Home>Security> Trusted Identities) and whether the signed content has already been changed since it was signed.

You can configure the preferences in advance to decide whether signature validation occurs automatically when the signed document is opened.

Set signature verification preferences

  1. Do any of the following to open the Preferences dialog box and then under the categories, select Signatures on the left:

    • Click the Document Properties/Preferences shortcuts located at the top of the vertical scrollbar and select Preferences.

    • Press Ctrl + K on your keyboard.

    • Choose File > Preferences.

  1. Under Verification, click More… and in the Signature Verification dialog box, check Verify signatures when the document is opened to enable automatically validating all signatures in a PDF document when it is opened. Select the following options as needed and then click OK:

  • Verification Behavior.

    • When Verifying. This allows you to choose a method to use for verifying signatures.

    • Require certificate revocation checking to succeed whenever possible during signature verification. This checks certificates against a list of excluded certificates during validation. If this option is deselected, the revocation status for approval signature is ignored. This option is selected by default.

  • Verification Time.

    • Verify Signature Using. Decide how to check the digital signature for validity. Time at which the signature was created is selected by default, meaning you can check the time based on when the signature was created. You can also choose to check based on the current time or the time set by a timestamp server when the document was signed.

    • Use expired timestamps. It allows using the secure time provided by the timestamp or embedded in the signature even though the signature’s certificate has already expired.

  • Windows Integration. Specify whether to trust all root certificates in the Windows Certificate Store when validating signatures or certified documents. Note that selecting either of these options may result in arbitrary material being treated as trusted content. We suggest you don’t trust all root certificates since some of the certificates from the Windows Certificate Store were not designed to be used for building trusted identities.

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