Indiana Code Title 36. Local Government § 36-7-23-25

(1) shall be executed by the manual or facsimile signature of the chair of the board;

(2) shall be attested by the manual or facsimile signature of the secretary of the board;

(3) shall be imprinted or impressed with the seal of the authority;

(4) may be authenticated by a trustee, registrar, or paying agent;  and

(5) constitute valid and binding obligations of the authority, even if the chair, the secretary, or both, whose manual or facsimile signature appears on the bond, no longer hold those offices.