A node device in a network system includes a memory and a processor. The node device is identified with a first value related to a first element and a second value related to a second element. The memory stores a first key corresponding to the first value, a second key corresponding to the second value, first information on a first range of values and second information on a second range of values, at least one of the first key and the second key being shared by at least three or more node devices in the network system. The processor communicates with one of at least three or more node devices indicated by the first value related to the first element and the second value related to the second element using one of the first key and the second key.