Minn. Stat. § 574.01: BONDS, REQUISITES AND EXECUTION.

Save when otherwise specially provided by statute, every bond, recognizance, or undertaking required or permitted to be made, given, tendered, or filed for the security or protection of the state, or of any person, corporation, municipality, or department thereof, or any other organization whatever and conditioned for the doing or not doing of anything in such instrument of security specified, shall be signed by one or more sureties, who shall justify as provided in section 574.12. Every bond or recognizance shall also be signed by the principal, and every bond shall be acknowledged by the principal and sureties.