An access control system for a people conveyor control system, includes an authentication proving device adapted to communicate with a people conveyor control system. The authentication proving device has a central processor unit and a read protected memory protected from read and write access by external applications. The authentication proving device stores in its read protected memory program code to carry out a verification procedure in response to a verification request from the people conveyor control system, and sends a verification signal to the people conveyor control system. The people conveyor control system in response to the verification signal selectively allows or denies access to at least one of specific sections of said people conveyor control system or specific functions implemented in the people conveyor control system.