The principal of and interest on any bonds issued by the authority shall be secured by a pledge of the revenues, rentals, and receipts out of which the same shall be made payable and may be secured by a trust indenture or mortgage or deed of trust (including assignment of leases or other contract rights of the authority thereunder) covering all or any part of the facilities from which the revenues, rentals, or receipts so pledged may be derived, including any enlargements of and additions to any such facilities thereafter made.
SDCL 1-16A-43