Requirements, governance and enterprise review
Trust and data-handling boundaries
Trust zones and what may cross them: classification per zone, and the explicit gates between zones.
ddn@1New DDN source
Why use it?
Security reviews fail on unstated boundaries; the diagram forces every crossing to have a name.
When it helps
Threat modeling, compliance reviews, or designing data flows across trust levels.
How to read it
- Zones carry classification labels; every arrow crossing a zone edge is a gate with a rule.
- Inside a zone, flows are routine; between zones, they are decisions.
What you need
- The zones and their classifications
- The gates and their rules
- What data may never cross
Things to check
- Do not mark a boundary as trusted because it is inconvenient to gate.
- Do not let a "temporary" bridge become the permanent path.
Scope of this diagram
Boundary documentation; no security evaluation or certification is implied.
Work with the converted example
- Open the viewer and select
diagram. Inspect the rendered view and its source. - Open the designer. Keep the selected profile and inspect its legal palette and property controls.
- Change one displayed title or an appropriate data value. Apply the edit and check the resulting diagram.
- Run the verifier and review its diagnostics before moving complete content into review.
- Download your edited DDN source to retain the change.
The example uses the indentation-based ddn-next-1 dialect. The language guide explains reusable definitions, dotted data rows and explicit property blocks.