外僑居留證 / 台灣地區居留證

Detects 外僑居留證 / 台灣地區居留證 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

tw

Frameworks

ISO 27001, ISO 27701

Data categories

pii, government-id

Scope

narrow

Risk rating

9

Platform compatibility

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

Pattern

\b[A-Z][A-D]\d{8}\b

Corroborative evidence keywords

ARC, TARC, resident certificate, 居留證, ID number, identification, ID card, license, permit, registration, certificate, field, column, row, entry, record, value, form, register, database (+20 more)

Proximity: 300 characters

Should match

• AA12345678 — ARC with region A, type A
• BC98765432 — ARC with region B, type C
• FD45678901 — ARC with region F, type D

Should not match

• AE12345678 — Invalid second letter (E)
• A123456789 — Digit in second position instead of A-D
• template example placeholder record identifier — Template/sample context should be excluded even when anchor words are present

Known false positives

• Two letters followed by eight digits may match some reference codes, but the A-D constraint on the second letter reduces false positives. Mitigation: The structured format with limited second-letter range 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

• Taiwan Resident Certificate (ARC/TARC) entity definition - Microsoft Learn