So far, none of the machines have passed the Nevada Gaming Commissions inspections. That would be the minimum criteria. Machines that don't at least pass this

So far, none of the machines have passed the Nevada Gaming Commissions inspections. That would be the minimum criteria. Machines that don't at least pass this level of scrutiny (all of them) are not something you can trust. That commission has long experience inspecting devices to ensure that they are fair and impervious to unobservable tampering. Once someone actually manufactures such a machine, then it needs to be used in a system that can detect fraudulent behavior, just like banks do. The system must require an official id, and must ensure voting privacy (sorry - mail-in ballots fail on both of these). It does no good to have a great machine if it will be subject to adulterated or coerced input.