Gets or sets what opening the document with the user password permits. The default is All.
public PdfPermissions Permissions { get; set; }
ISO 32000-2 §7.6.4.2, Table 22: written as the P entry, with the reserved bits set and bit 10 set (PDF 2.0 writers shall
set it), and bit 13 set unless IntegrityProtection requires a MAC (ISO/TS 32004 §5.1.2). Values outside
All are ignored. Readers are expected to respect the permissions; nothing in PDF enforces them (§7.6.4.1).