S.D. Codified Laws § 33A-1-21

The contents of, and all files, records, reports, papers, and documents pertaining to, any claim for the benefits of this chapter, or chapters 33A-2 to 33A-5, inclusive, whether pending or adjudicated, are confidential and privileged except to the veteran, a veteran's dependents or their duly authorized agents. However, investigatory material compiled solely for the purpose of determining suitability, eligibility, or qualifications for the benefits of this chapter, or chapters 33A-2 to 33A-5, inclusive, are exempt from release to the extent that the disclosure of the material would reveal the identity of the source who furnished information to the department under an express promise that the identity of the source would be held in confidence, or, prior to July 1, 1985, under an implied promise that the identity of the source would be held in confidence.