A method for updating firmware on a control module of a modular assembly system is provided. Information related to noise sampled from the control module is obtained. A first encryption key is calculated based on the information. Firmware to be updated on the control module is received from a host of the modular assembly system. The firmware is encrypted based on at least a second encryption key. In response to determining that the received firmware can be decrypted, the decrypted firmware is loaded into the control module. At least one of the obtaining, calculating, receiving, determining, and loading is performed by the control module.