Secure data transmission between an input device and both industrial controllers in a high-availability system utilizes a secure connection established between the primary industrial controller and the input device. Data required to establish the secure connection is stored on the primary controller as part of the connection data corresponding to the secure connection. The input device transmits data to the primary controller over the secure connection according to the desired level of security. The primary controller transmits the connection data defining the secure connection to the secondary controller. If a failure occurs in the primary controller, the secondary controller establishes a connection to the input device using the connection data for the secure connection, such that the secondary controller may assume responsibility for the controller end of the secure connection. The primary controller transmits the input signals to the secondary controller via the dedicated connection between controllers.