S.D. Codified Laws § 12-4-5.5
At the time voter registration information is transmitted from a county to the statewide voter registration file, the secretary of state shall verify the authenticity of the driver license number or the South Dakota nondriver identification number with the driver license database. If the last four digits of the person's social security number have been provided, the secretary of state shall review the social security database to determine that the number, name, and date of birth are accurate and that this information belongs to the person. If any of this information is reported as not being accurate, the county auditor must withdraw the voter registration and attempt to get the correct information with the process provided in § 12-4-5.3. The State Board of Elections shall promulgate rules, pursuant to chapter 1-26, determining technical parameters for the driver license and social security database verification.
SDCL 12-4-5.5