Cartão de Cidadão

Detects Cartão de Cidadão patterns. This pattern is based on a Microsoft Purview built-in sensitive information type. Users already running Purview may prefer to enable the built-in SIT directly, or use this version as a starting point for customisation.

Type

regex

Engine

universal

Confidence

high

Confidence justification

High confidence: pattern has strong structural constraints (specific format, prefix, or character class restrictions) that significantly reduce false positive rates. Added context gating and exclusion rules improve precision and reduce incidental matches.

Detection quality

Verified

Jurisdictions

eu, pt

Regulations

BDSG, CNIL / LIL, GDPR

Frameworks

ISO 27001, ISO 27701

Data categories

pii, government-id

Scope

narrow

Risk rating

5

Platform compatibility

Purview: Compatible, GCP DLP: Compatible, Macie: Compatible, Zscaler: Compatible, Palo Alto: Compatible, Netskope: Compatible

Pattern

\b\d{8}\s?\d\s?[A-Z]{2}\d\b

Corroborative evidence keywords

cartão de cidadão, citizen card, bilhete de identidade, ID number, identification, ID card, license, permit, registration, certificate, field, column, row, entry, record, value, form, register, database, extract (+19 more)

Proximity: 300 characters

Should match

• 12345678 9 ZZ4 — Portuguese citizen card with spaces
• 987654321AB2 — Portuguese citizen card without spaces
• 45678901 2 CD3 — Another citizen card format

Should not match

• 1234567 9 ZZ4 — Too few digits in first group
• 12345678 9 Z4 — Only one letter
• template example placeholder record identifier — Template/sample context should be excluded even when anchor words are present

Known false positives

• The mixed alphanumeric format with specific structure is relatively distinctive. Mitigation: The structured format with embedded letters provides good validation. Keyword context further improves accuracy.
• In multiple languages, similar terminology used in formal or administrative contexts (education, professional documentation) that does not constitute sensitive data collection. Mitigation: Layer with additional contextual signals such as structured identifiers, form fields, or database column headers to distinguish sensitive records from general references.

References

• Portugal Citizen Card Number entity definition - Microsoft Learn