Indonesian resident identity number, the NIK on the KTP card: sixteen digits, a two digit province code and four more digits of region, then the birth date as DDMMYY where a female holder has forty added to the day, then a four digit serial. Purview documents the province code, the four digits and the DDMMYY date; the plus forty rule for women is why the day range runs to seventy one. Cloudflare publishes 3203012503770011 as its sample. Reproduced collision: sixteen digits sits inside the CREDIT_CARD window of thirteen to nineteen digits, so every NIK is also a candidate card number and only the Luhn check or a keyword tells them apart.
Label: ID_NIK
(?<!\w)\d{6}(?:0[1-9]|[12]\d|3[01]|4[1-9]|[56]\d|7[01])(?:0[1-9]|1[0-2])\d{6}(?!\w)The KTP number 3203012503770011 is printed on the card. → 3203012503770011NIK 1271016512880002 adds forty to the day for a female holder. → 1271016512880002320301250377001320301350377001132030125037700111Tags: id, government-id, identity