Patent ID: 8416949

Claim:
An actor node capable of mutually communicating with a sensor node arranged in a predetermined region divided into a plurality of blocks, the actor node obtaining data generated by the sensor node from the sensor node arranged in a block covered by the actor node, the actor node comprising: a key acquisition unit for obtaining, from a predetermined device, key information including a key used for communication with another actor node, key generation information for generating a key used for communication with the sensor node arranged in a coverage block, and a hash chain having a predetermined length unique to the coverage block; and a dynamic change unit for temporarily changing the coverage block in which data are obtained from the sensor node and temporarily causing the another actor node to obtain, on behalf of the actor node, data from the sensor node arranged in a partial region of at least a portion of the coverage blocks, wherein the key acquisition unit and the dynamic change unit are implemented by a central processing unit (CPU), and wherein the dynamic change unit obtains identification information unique to the another actor node from the another actor node, the dynamic change unit notifies, to the sensor node arranged in the partial region, the identification information unique to the another actor node and an identifier indicating temporary change of the actor node performing data collection, the dynamic change unit notifies, to the another actor node, a portion of the hash chain and a temporary key generated using the identification information unique to the another actor node and the key used for communication with the sensor node arranged in the partial region.