A small program for reading PESEL numbers.
This very small piece of software decodes PESEL numbers (think SSNs for Polish citizens) into C structs. The following information is encoded in a PESEL number (11 digits long; the positions are zero-indexed):
Date of Birth (positions 0-5)
Gender (position 9)
Checksum (position 10)
The PESEL Reader is based on the official specification, as published by the Ministry of the Interior of the Republic of Poland.