On the one hand, KNX Secure extends the KNX IP protocol to ensure reliable protection of transmitted data (KNX IP Secure). On the other hand, KNX Secure protects the traditional KNX protocol by means of encryption and authentication. The safety mechanisms are already in place during the protected start-up of the KNX system via the ETS. Subsequently, during operation, data communication, e.g. between actuators and sensors, is effectively protected against unauthorised access, manipulation and eavesdropping.