Editing National identification number (section)

=== Czech Republic and Slovakia ===
[[Czech Republic]] and [[Slovakia]] uses a system called Birth Number (Czech/Slovak: rodné číslo (RČ)). The system was introduced in the former [[Czechoslovakia]].

The form is YYXXDD/SSSC, where XX=MM (month of birth) for male (numbers 01–12) and XX=MM+50 for female (numbers 51–62), SSS is a serial number separating persons born on the same date and C is a check digit, but for people born before 1 January 1954 the form is without the check digit - YYXXDD/SSS. This enables the system to work until the year 2054. The whole number is usually divisible by 11.<ref>{{Cite web |url=https://phpfashion.com/jak-overit-platne-ic-a-rodne-cislo |title=Jak ověřit platné IČ a rodné číslo? |access-date=2023-05-14 |archive-date=2023-05-14 |archive-url=https://web.archive.org/web/20230514005717/https://phpfashion.com/jak-overit-platne-ic-a-rodne-cislo |url-status=live }}</ref>

The system is raising privacy concerns, since the age and the sex of the bearer can be decoded from the number. Therefore, the birth number is considered a sensitive piece of personal information.

In a law that took place in the year 2004, a failsafe system has been implemented, where in case all valid serial numbers get depleted for a day, the number 20 gets added to the value of XX. This means that XX can get up to 32 for males, and 82 for females.