A remote digital firing system includes a firing circuit operative to fire remote mission payloads, a firing control panel linked to the firing circuit, and a digital code plug configured to communicate with the firing circuit and firing control panel. The firing circuit can generate, write and store one-time random session variables to the digital code plug. The firing circuit validates digital messages received from the firing control panel by comparing one-time random session variables embodied in the messages with the stored one-time random session variables, before firing the payload.