T10-R4 in five minutes
Wikipedia's personal-data page says personally identifiable information is information related to an identifiable person, and that legal definitions differ by place.
That page quotes NIST SP 800-122: information that can distinguish or trace an identity, and other information that is linked or linkable.
It says information that might not count as PII under HIPAA can still be personal data under the GDPR. One definition is not universal.
Replacing a name and leaving a unique account number is not finished. A linked field can still identify.
This page is not a redaction product and not legal advice.
Masking is a learning habit: find every field that can pick out the person, not only the name. Confirm the definition that applies before you rely on it.
Sources and go deeper
- Personal data — Wikipedia wikipedia The page title is Personal data. last checked 2026-10