S.D. Codified Laws § 19-19-507

A person has a privilege, which may be claimed by him or his agent or employee, to refuse to disclose and to prevent other persons from disclosing a trade secret owned by him, if the allowance of the privilege will not tend to conceal fraud or otherwise work injustice. If disclosure is directed, the court shall take such protective measures as the interest of the holder of the privilege and of the parties and the interest of justice require.