11. Security Considerations

The notation is a markup language for archival text; processing untrusted input nonetheless warrants care.

11.1 Resource exhaustion

Constructs nest (containers, §7.3) and forward references scan preceding text (§7.5). A naive look-back that rescans from the document start for every reference is quadratic in the number of references; a deeply nested or highly pathological document can drive memory and time up. A processor SHOULD bound look-back cost (e.g. an index of candidate targets) and SHOULD bound nesting depth, degrading gracefully (a generic annotation) rather than consuming unbounded resources.

11.2 Reserved-code-point confusion

A processor that uses private-use code points as internal markers (§3.4) MUST neutralize any such code point appearing in the source (§4.4) and report source-contains-pua; otherwise crafted input could forge internal markers and corrupt the placeholder mapping, mis-attributing or mis-rendering spans.

11.3 Encoding confusion

Input may be Shift_JIS or UTF-8 (§3.1). Mis-detecting the encoding can change which bytes form a delimiter and therefore which constructs are recognized. A processor SHOULD obtain the encoding out of band where possible, and MUST replace undecodable bytes with U+FFFD rather than guessing a delimiter.

11.4 Output-context injection

The reference HTML (§8) escapes the five HTML-significant ASCII characters. A processor emitting HTML (or any other structured output) MUST escape for its output context; gaiji descriptions, annotation bodies, and resolved targets are author-controlled text and MUST NOT be emitted into markup unescaped.

11.5 Gaiji table trust

Gaiji resolution (§6.4, Annex B) maps men-ku-ten and descriptions to Unicode via data tables. A processor SHOULD treat those tables as a trusted, versioned input; a wrong mapping silently substitutes a different glyph. Unresolved references degrade visibly (unresolved-gaiji) rather than guessing.