Forty-five days from discovery
Section 24-4.9-3-3 requires disclosure "without unreasonable delay, but not more than forty-five (45) days after the discovery of the breach." The 45-day limit was added by a 2022 amendment, P.L.171-2022.
The section treats a delay as reasonable if it is necessary to restore the integrity of the computer system, necessary to discover the scope of the breach, or requested by the attorney general or a law enforcement agency because disclosure would impede a criminal or civil investigation or jeopardize national security. Once that reason ends, disclosure must follow as soon as possible. The section does not say whether such a delay can run past the 45 days.