Key Management Scheme in WSN Based on Property of Circle

In view of the situation that wireless sensor networks have some features like limited resources, the vulnerability, the frequent changes in network topology, this paper puts forward a designed key management in WSN which is based on the geometric properties of circle. This scheme can guarantee that without changing the information stored in the nodes, it is possible to update the key. And compared with the existed WSN key management scheme ,the program is simple, convenient and efficient; it has greater advantages in storage overhead, computation overhead, communication overhead and the dynamic topology.