Set preferences for validating digital signatures

Select Menu > Preferences.

Select Signatures under Categories.

Select More from the Verification option.

In the dialog box that opens, modify the following settings as needed:

• Verify signatures when the document is opened: Acrobat automatically validates all the signatures when a PDF is opened.
• Verification Behavior: Set the plugin to verify a signature when a PDF is opened.
• Require certificate revocation checking to succeed whenever possible during signature verification: Acrobat checks certificates against a list of excluded certificates during validation.
• Use expired timestamps: Use the time mentioned in the timestamp or embedded time in the signature even if the signature certificate has expired. If you deselect the checkbox, Acrobat discards expired timestamps.
• Verification Time: Check the time at which the signature was created or embedded in the PDF.
• Verification Information: Select when to alert the user when verification information is too large.
• Trust ALL root certificates in the Windows Certificate Store for (Windows only): Specify when to trust root certificates in the Windows certificate store.
  • Validating signatures: Certificates are trusted for Acrobat Approval signature validation.
  • Validating certified documents: Certificates are trusted for certification signature validation.

Select OK.

Select Acrobat > Preferences.

Select Signatures under Categories.

Select More from the Verification option.

In the dialog box that opens, modify the following settings as needed:

• Verify signatures when the document is opened: Acrobat automatically validates all the signatures when a PDF is opened.
• Verification Behavior: Set the plugin to verify a signature when a PDF is opened.
• Require certificate revocation checking to succeed whenever possible during signature verification: Acrobat checks certificates against a list of excluded certificates during validation.
• Use expired timestamps: Use the time mentioned in the timestamp or embedded time in the signature even if the signature certificate has expired. If you deselect the checkbox, Acrobat discards expired timestamps.
• Verification Time: Check the time at which the signature was created or embedded in the PDF.
• Verification Information: Select when to alert the user when verification information is too large.
• Trust ALL root certificates in the Windows Certificate Store for (Windows only): Specify when to trust root certificates in the Windows certificate store.
  • Validating signatures: Certificates are trusted for Acrobat Approval signature validation.
  • Validating certified documents: Certificates are trusted for certification signature validation.

Select OK.