Every United States citizen is required to hold a Social Security number, since it identifies you for tax and national insurance purposes. But that number, even more than other types of personal identification, is very personal and should be kept confidential to prevent identity crimes. You should not seek access to SSNs of living third parties, or use a number you come across in any way, since you might be committing a crime. On the other hand, if someone is deceased, you can use his SSN to find out his date of birth by searching the Social Security Death Index.

The Social Security system provides a national insurance program for working Americans and their families. It offers both retirement benefits and disability and death benefits to someone who has met the number of required work years. Family members, including spouse and children, also can be covered by this protection if they meet the requirements.

Social Security is a pay-as-you-go system. Working Americans pay a Social Security tax that is deposited into the Social Security Trust Fund, which is used to pay out benefits to those entitled to them. Up to a certain point, the more you pay, the larger benefits you or qualified family members are entitled to.

To keep track of how much each person pays into the system, an individual is issued a nine-digit Social Security number. This number is a prerequisite to employment as well as to applications for benefits. It is also used as a core identification for financial transactions. The government urges you to keep your SSN very private and confidential, since someone holding the number may try to take out loans or get credit in your name, or even assume your identity.

It's a crime to use another person's SSN, so if you happen across a third-party SSN, you should not attempt to use it to determine the person's date of birth. However, if the person is deceased, you can access the Social Security Death Index and obtain information about them, including their date of birth.

The Social Security Death Index (SSDI) is a database of death records. It was created by the Social Security Administration from the agency's Death Master File Extract. It includes the names of the persons with SSNs whose deaths were reported to the SSA from 1936 through the present. However, in 2014, a law was passed that imposed a three-year-post-death delay on releasing death information. The index provides information on the deceased person, including date of birth and date of death.

You can access the SSDI online at Ancestry.com, if you become a member. Free online access is available at GeneologyBank.com or FamilySearch.com. Simply fill out the name and any information you have, including the SSN. In this way, if someone is deceased, you can use the SSDI to find a birthday with a Social Security number.