Method for securely authenticating a sensor or an actuator of a home automation system in a home by means of a computer network outside the home using a first communication apparatus for establishing a wireless network connection, the sensor or actuator - being equipped with or being able to be connected to a second apparatus for establishing an at least partially wireless network connection and, for logging onto the computer network, - comprising an address of the computer network and identification data which are stored in storage elements, and the first communication apparatus - comprising application software (App) which is implemented in a storage element and is intended to access access and identification data relating to a network connection of the first communication apparatus, having the following steps: (a) establishing an at least partially wireless network connection between the sensor or actuator and the computer network, (b) establishing a wireless network connection between the first communication apparatus and a computer network by means of the application software, characterized in that the method also comprises the following steps: (c) producing two substantially identical digital data strings, digital signals from the first communication apparatus being used to produce a first digital data string, and digital signals from the sensor or actuator being used to produce the second digital data string, (d) first transmission of an item of information in the form of the first digital data string from the first communication apparatus to the computer network via the wireless network connection, (e) second transmission of the information in the form of the second digital data string from the sensor or actuator to the computer network via the at least partially wireless network connection, (f) comparing the first digital data string and the second digital data string in the computer network, (g) authenticating the sensor or actuator in the event of a positive result of the comparison, a match between the first and second data strings being required in order to achieve a positive result of the comparison. - being equipped with or being able to be connected to a second apparatus for establishing an at least partially wireless network connection and, for logging onto the computer network, - comprising an address of the computer network and identification data which are stored in storage elements, and - comprising application software (App) which is implemented in a storage element and is intended to access access and identification data relating to a network connection of the first communication apparatus, (a) establishing an at least partially wireless network connection between the sensor or actuator and the computer network, (b) establishing a wireless network connection between the first communication apparatus and a computer network by means of the application software, (c) producing two substantially identical digital data strings, digital signals from the first communication apparatus being used to produce a first digital data string, and digital signals from the sensor or actuator being used to produce the second digital data string, (d) first transmission of an item of information in the form of the first digital data string from the first communication apparatus to the computer network via the wireless network connection, (e) second transmission of the information in the form of the second digital data string from the sensor or actuator to the computer network via the at least partially wireless network connection, (f) comparing the first digital data string and the second digital data string in the computer network, (g) authenticating the sensor or actuator in the event of a positive result of the comparison, a match between the first and second data strings being required in order to achieve a positive result of the comparison.