Secure power supply for an industrial control system

A control system includes an electrical power source and an alternating current (AC) power supply electrically coupled with the electrical power source. An uninterruptable power supply is electrically coupled with the AC power supply for storing and returning electrical energy supplied by the AC power supply. The uninterruptable power supply includes multiple battery modules. Each battery module includes a battery cell and a battery monitor configured to monitor the battery cell. Each battery module also includes a controller operatively coupled with the battery modules. The controller is configured to receive diagnostic information from the battery modules. The uninterruptable power supply can also include one or more authentication modules to participate in an authentication sequence between two or more of a battery module, the controller, a device to be coupled with the uninterruptable power supply, an action originator in the control system, and so forth.