Indiana Code Title 3. Elections § 3-11-15-37

Sec. 37. Ballot card voting systems must rely on the retention of ballots as a redundant means of verifying election results. As a means of assuring accuracy in electronic voting systems, the unit must incorporate multiple memories in the machine itself and in the unit's programmable memory devices. To attain a measure of integrity over the process, an electronic voting system must also maintain images of each ballot that is cast so that records of individual ballots are maintained by a subsystem independent and distinct from the main vote detection, diagnostic, processing, and reporting path.