The story of the social security number.

The use of the Social Security number (SSN) has expanded significantly since its inception in 1936. Created merely to keep track of the earnings history of U.S. workers for Social Security entitlement and benefit computation purposes, it has come to be used as a nearly universal identifier. Assigned at birth, the SSN enables government agencies to identify individuals in their records and businesses to track an individual's financial information. This article explores the history and meaning of the SSN and the Social Security card, as well as the Social Security Administration's (SSA's) SSN master file, generally known as the Numident. The article also traces the historical expansion of SSN use and the steps SSA has taken to enhance SSN integrity.