A complex data type that represents the actions that can
be performed in the PDF document without invalidating the signature.
The PDFSignaturePermissions value is a member of
the PDFSignatureVerificationInfo and PDFSignatureVerificationResult data
These string values are valid:
- All modifications to the PDF document are allowed.
- Only modifications to the form fields are allowed.
- Only modifications to the form fields and comments are allowed.
- Modifications to the PDF document are not allowed.