Indiana Constitution Article 11 Section 3
If the General Assembly shall enact a general banking law, such law shall provide for the registry and countersigning, by an officer of State, of all paper credit designed to be circulated as money; and ample collateral security, readily convertible into specie, for the redemption of the same in gold or silver, shall be required; which collateral security shall be under the control of the proper officer or officers of State.