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A Norwegian fødselsnummer or D-number — two valid mod-11 check digits and a plausible date — appears in the free text.
What it looks at#
An 11-digit DDMMYY + 3-digit individual number + 2 check digits, where both chained
mod-11 checksums (the standard fødselsnummer algorithm) verify. A D-number (issued to
people without a Norwegian fødselsnummer, e.g. some foreign workers) uses the same shape
with the day of birth offset by +40 — a day of 41-71 is treated as exactly as valid as
01-31.
Why it matters#
Norway’s national identity number is used across banking, healthcare, tax and government services — high severity for the same reason as the Swedish personnummer: paired with a name, it’s often sufficient for identity fraud.
What to do#
High severity. Redact before storing or forwarding.