Test spreadsheet redaction beyond visible cells
A workbook can contain sensitive details outside the active sheet, and replacing a value can change a calculation. Evaluate confidentiality and analytical usefulness together before relying on a sanitized spreadsheet in an AI workflow.
For Finance operations, data owners and security evaluators
A fictional supplier-spend workbook
An analyst wants category-level trends from a synthetic workbook. Supplier contact details should be removed, while category totals and the meaning of the analysis must remain reliable.
What you are working with
- A workbook with synthetic supplier details, numeric totals, formulas and a second hidden test sheet.
- Separate test fixtures in comments and named ranges, with external references listed for review.
- An expected-results sheet maintained outside the tested workbook, showing permitted totals and required removals.
A safer approach
- Agree the exact workbook features in scope; do not treat a visible-cell result as whole-workbook coverage.
- Use fictional financial records and disable unrelated external connections before running the controlled evaluation.
- Compare outputs in the spreadsheet application used by the analyst and keep a clean original for reference.
Expected outcome: The evaluated workbook removes the agreed sensitive content without introducing unexplained calculation changes, or unsupported structures are excluded from the approved workflow.
Work through the procedure
Map where information lives
Inventory visible sheets, hidden sheets, comments, named ranges and formulas before the run. Record which locations contain synthetic fixtures and whether any values are duplicated. This map belongs in the evaluator's evidence pack; it is not a claim that the security tool inventories these features.
Define permitted calculations
Identify the questions the analyst needs answered and calculate expected totals from the original fixture. Decide which identifiers can be replaced without breaking relationships. If a formula depends on a protected value, agree whether its result should remain, be removed or require manual preparation.
Inspect the resulting workbook
Run the agreed redaction workflow and inspect the actual output where available. Unhide test sheets, review comments and search the documented fixture locations. Check cell types as well as visible values: text replacing a number may affect later analysis even when the sheet looks normal.
Recalculate and assess meaning
Open and recalculate the sanitized workbook in the chosen spreadsheet application. Compare totals, references and error values with the expected-results sheet. Review any cached or displayed results that differ, and decide whether the output is suitable for the intended AI question.
What to check before proceeding
1. Workbook content scope
- Ready when
- All agreed locations have an inspection result, including hidden content in the approved scope.
- If the check fails
- Require source preparation or exclude the unverified workbook feature before sharing.
2. Formula behavior
- Ready when
- Calculations match the approved expectation and no unexplained reference or value errors appear.
- If the check fails
- Inspect changed cell types and dependencies before accepting the output.
3. Analytical usefulness
- Ready when
- The sanitized workbook supports the original permitted question without misleading totals or groupings.
- If the check fails
- Export a purpose-built synthetic or aggregated table instead of the full workbook.
Common mistakes to avoid
- Reviewing the active tab alone and treating a workbook's hidden content as automatically protected.
- Preserving a displayed number while overlooking a broken formula that changes when the workbook recalculates.
Evaluate this workflow with Aona
Where Aona can help
Ask Aona sales and engineering to scope a workbook evaluation around your formulas, layouts and required redaction locations.
What to confirm
Confirm each spreadsheet feature separately. General Excel support does not promise hidden-sheet, formula, macro or external-link sanitization.
Evaluating a control for your organization?
Bring your target AI tool, device and acceptance criteria. Review the supported control path, the evidence you need and any limitations before deciding on a pilot.