You can change the trust settings of certificates to allow specific actions.
These timestamps are compliant with the timestamp and revocation features described in Part 4 of ETSI 102 778 If the signature status is unknown or unverified, validate the signature manually to determine the problem and possible solution.If the signature status is invalid, contact the signer about the problem.You also specify the types of changes that are permitted for the document to remain certified.For example, suppose that a government agency creates a form with signature fields.After reviewing the report, you can contact the author of the document about the problems listed in the report.
You can also use When you certify a PDF, you indicate that you approve of its contents.
When you receive a signed document, you may want to validate its signature(s) to verify the signer and the signed content.
Depending on how you have configured your application, validation may occur automatically.
When the form is complete, the agency certifies the document, allowing users to change only form fields and sign the document. However, if they remove pages or add comments, the document doesn’t retain its certified status.
You can apply a certifying signature only if the PDF doesn’t already contain any other signatures. A blue ribbon icon in the Signatures panel indicates a valid certifying signature.
For more information about signature warnings and valid and invalid signatures, see the Each time a document is signed using a certificate, a signed version of the PDF at that time is saved with the PDF.