Social Security number

A social security number is a nine digit number resembling "123-00-1234" which is issued to an individual by the Social Security Administration of the government of the United States.

Table of contents

1 Purpose and use 2 Structure 3 External Links

Purpose and use

The original purpose of this number was to administer the Social Security program, but it has come to be used as also been used as a "primary key" (a de facto national ID number) for individuals within the United States. Payroll, university student records, credit records, and driver's licenses are frequently indexed by Social Security number and hence disclosure and processing of these numbers is of major concern to privacy advocates.

Structure

The nine-digit Social Security number is divided into three parts.

• The first three digits are the area number. If the Social Security number was assigned before 1973 (when Social Security cards were issued by local offices) the area number reflects the State where the Social Security number was applied for. Since 1973, social security numbers have been issued through a central office. The first three digits of a social security number are determined by the ZIP code of the mailing address shown on the application for a social security number.

• The middle two digits are the group number. They have no special geographic or data significance but merely serve to break the number into conveniently sized blocks for orderly issuance.

• The last four digits are serial numbers. They represent a straight numerical sequence of digits from 0001-9999 within the group.

The British equivalent is a National Insurance number, generally called a NI Number, although it is generally only used to administer state benefits, and has not gained the ubiquity of its US equalalent.

External Links

• Social Security Administration
• Frequently Asked Questions on SSNs and Privacy
• The Woolworth Card - The SSN 078-05-1120 has been claimed by thousands of people since the late 1930s