National Identification Number - Austria - Social Security Number

Social Security Number

The Austrian Social Security Number (SSN) is a well-established identifier, and would identify in theory every Austrian citizen. Its format is a 3-digit serial number, a checksum digit and the birth date in an DDMMYY-notation. Because it contains the birth date, it is considered a privacy-sensitive number. For that reason, its use is restricted by law to certain areas of health care, social security, taxes, education and other administrative areas. That makes it unusable as a general person identifier, but pervasive enough to make it a threat to data privacy.

These numbers would have lasted for 800 people a day in theory. Practically there were other countries than Austria where birth was registered months after the real birthdate. These children got 1 January or 1 July as birthday. So sometimes there were months in the past where 800 was not enough. So fictional months were created like the 13, 14 or 15. So there are valid SSN like "1788011550" existing.

There are some practical disadvantages, too. It is being assigned without proper legitimating hence there are duplicates. It does not cover people without social security, although these are few in Austria. Some immigrants without papers from their homeland have their birth date changed (after understanding the pros and cons of being under a certain age). In general the SSN is a quite reliable identifier, but not good enough for classes of application that require qualified identification.