Fuente: Wipo "IOT" The invention relates to a communication method for IoT nodes (110) in a local network (100) which is connected to the Internet (200) solely via a computer (130). The local network (100) has an ethernet network or a single pair ethernet network. The IoT node is designed to be display-free and operating element-free and has a first interface for a communication with other IoT nodes in the local network (120). Each IoT node has a first public key and a first private key. The first private key is stored in advance or is generated by the IoT node itself. IoT nodes are authenticated by the process of transmitting a request for a root certificate to a root certificate server (210) by means of the computer, said root certificate server having at least one root certificate of the manufacturer of the IoT nodes, receiving and storing the root certificate, and checking whether the IoT nodes are original and unmodified devices using the received root certificate. The root certificate (Z) links the first public key of the IoT nodes to unique address information of the IoT node, said address information being valid solely in the local network. The computer checks whether the public key of the IoT node is signed by the manufacturer of the IoT node using the stored root certificate (Z), and the first key is checked on the basis of a cryptographic method.