Idaho Code § 67-503
When a bill has passed both houses of the legislature, and is returned by the governor without his signature and with objections thereto, and upon a reconsideration passes both houses by a two-thirds (2/3) vote, it must be authenticated as having become a law by a certificate indorsed thereon, or attached thereto, in the following form:
"This bill having been returned by the governor with his objections thereto, and after reconsideration having passed both houses, by a two-thirds vote, it has become a law this .... day of ...., ....," which indorsement, signed by the president of the senate and speaker of the house, is a sufficient authentication thereof. Such bill must then be deposited with the laws, in the office of the secretary of state.
Idaho Code § 67-503