Gotchas and Limits

No detector catches everything

Deterministic redaction is excellent for structured identifiers. It is not a universal privacy classifier. Free-form names, ambiguous addresses, and context-dependent secrets may need custom rules, NER, or upstream data minimisation.

Important limits:

  • regex heuristics can create false positives on address and phone-like text;
  • NER can miss entities and is allowed to fail open;
  • drop can alter sentence meaning;
  • token maps are recoverable PII;
  • salt rotation invalidates old hash and token joins;
  • overlap resolution intentionally discards later overlapping detections.