# PII Redaction

Detect and remove personal data before it reaches the model, logs, or downstream systems that don't need it.

## Why the CCAR-P exam tests this

The exam tests whether you minimize exposure of personal data across prompts, logs, and outputs rather than trusting the model to keep it safe.

## Definition

**PII redaction** is detecting **personally identifiable information** — names, emails, government IDs, card numbers, health data — and removing or masking it at the boundaries where it isn't needed. It is a concrete expression of **data minimization**: the less sensitive data flows through a component, the less can leak from it.

Redaction applies at multiple points and connects to **guardrail placement**: scrub PII on **input** before it enters the prompt or is sent to a third-party model, scrub it from **logs and traces** so debugging data isn't a breach waiting to happen, and screen **output** so the model can't emit PII to an unauthorized recipient. Where the model genuinely needs an identifier, prefer **tokenization** (a reversible placeholder) so the raw value never travels further than required.

Redaction is a **named control** in the register — with an owner and evidence (detection coverage, test results) — and it should **fail closed**: if the detector errors on a field, treat the data as sensitive rather than passing it through in the clear.

## Exam trap

"We log full prompts and responses for debugging" is the trap — unredacted logs quietly become the largest PII exposure surface in the system.

## Commonly confused with

- **guardrail-placement** — Redaction is a control that runs at the input/output/log boundaries that guardrail placement defines.
- **least-privilege** — Least-privilege limits who can access data; redaction removes the data from where it isn't needed at all.

## Related

- guardrail-placement
- least-privilege
- compliance-control-register
- fail-closed-vs-fail-open

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Source: Claude Cert Prep — an independent, unofficial CCAR-P study resource (domain P5). Not affiliated with Anthropic.