The method of operating control network system and control network

A control network system connected with a node having a unique identifier includes a KDC4B for distributing a first key to the node for cryptographic communication, a PS4B for supplying a function name and a second key corresponding to the unique identifier to the node by the cryptographic communication using the first key, and a PS for supplying the node with setting information used for the cryptographic communication using the second key in response to a request using the function name.