Mainly, the PC inside ATM should not do anything remotely security critical. PC-based ATM platforms are actually designed around compartmentalization and in ide

Mainly, the PC inside ATM should not do anything remotely security critical. PC-based ATM platforms are actually designed around compartmentalization and in ideal case the PC should only draw UI on screen, handle some subset of input events and route encrypted messages between other components of the ATM (whether it's implemented in this way in actual deployments is another issue).