PdfDocument doc = new PdfDocument();

doc.SecuritySettings.DocumentSecurityLevel = PdfDocumentSecurityLevel.None;

doc.SecurityHandler.OwnerPassword = "XXX";
doc.SecuritySettings.OwnerPassword = "XXX";

doc.SecuritySettings.PermitAccessibilityExtractContent = false;
doc.SecuritySettings.PermitAnnotations = false;
doc.SecuritySettings.PermitAssembleDocument = false;
doc.SecuritySettings.PermitExtractContent = false;
doc.SecuritySettings.PermitFormsFill = false;
doc.SecuritySettings.PermitModifyDocument = false;

doc.SecuritySettings.PermitPrint = true;
doc.SecuritySettings.PermitFullQualityPrint = true;