28 CFR 802.23 - Use and disclosure of social security numbers.
(a) In general. An individual shall not be denied any right, benefit, or privilege provided by law because of such individual's refusal to disclose his or her social security number.
(b) Exceptions. The provisions of paragraph (a) of this section do not apply with respect to:
(1) Any disclosure which is required by Federal statute, or
(2) The disclosure of a social security number to any Federal, State, or local agency maintaining a system of records in existence and operating before January 1, 1975, if such disclosure was required under statute or regulation adopted prior to such date to verify the identity of an individual.
(c) Requests for disclosure of social security number. If the Agency requests an individual to disclose his or her social security account number, we shall inform that individual whether:
(1) Disclosure is mandatory or voluntary.
(2) By what statutory or other authority such number is solicited, and
(3) What uses will be made of it.