pii.national_id_de
A German Steuer-ID / IdNr appears near a recognisable label like "Steuer-ID" or "IdNr" in the free text.
What it looks at#
An 11-digit number, first digit non-zero, whose 11th digit matches the ISO 7064 MOD 11,10
check digit computed from the first ten, and a label — Steuer-ID, IdNr, or
Steuer(liche) Identifikationsnummer — within about 40 characters of it. A real Steuer-ID
also constrains which digit may repeat among the first ten and how; this check verifies
only the MOD 11,10 check digit, which alone accepts roughly one random 10-digit prefix in
ten — “weak” enough on its own that D-78 requires the nearby label as well.
Why it matters#
The Steuer-ID is Germany’s lifetime tax identifier, used well beyond tax filings — employers, banks and public authorities all reference it.
What to do#
High severity when it fires. Because this check requires a label nearby, a bare Steuer-ID-shaped number with no such label present will not be caught — a known gap, not a false negative in the usual sense.