Secret Sharing Scheme and Key Sharing Scheme Suitable for Clustered Sensor Networks

A clustered sensor network collects two or more nodes and makes a cluster from them. Generally a cluster head (CH) has all the encryption keys of the nodes in a cluster and performs encrypted communication. However, this type of network has a problem in that the keys are revealed if the CH is analyzed every time after key sharing. Moreover, when all the nodes are set to CH, another problem arises, which is the need for large storage for holding the keys of all the nodes in a cluster. In this paper, we propose the first key sharing scheme that carries out key sharing with the CH and each node in a cluster and that realizes information theoretical security using a secret sharing scheme, even if the CH is analyzed except for the time of encryption communication. Next, we propose the second key sharing scheme in which additional storage for the CH for saving the keys of all the nodes in a cluster is not needed. In order to realize it, the secret sharing scheme is improved and the security is evaluated. In addition, we present the third key sharing scheme in which none of the keys are revealed at all even if CH or all the child nodes are analyzed.