Research On Group Key Management Schemes For Wireless Sensor Networks

Wireless sensor networks (WSN) consist of low-cost, low power tiny sensor nodes which can communicate with each other to perform sensing and data processing cooperatively in ad-hoc manner. Due to the characteristic of wireless sensor network, it has a very wide range of applications, especially in recently years, it has a very rapid development.However, with an overall improvement in technology, the application conditions of wireless sensor networks are becoming more sophisticated, also the security issues become essential.Many applications of wireless sensor networks are built on the pattern of group communication, so the confidentiality and integrity of information is achieved with the group key, which needs to be updated upon group members changing. Therefore, how to manage group key effectively and securely is a very valuable topic.The thesis reviews the historical context, applications of wireless sensor networks, and discusses security problems and means of defense and then focuses on two types of group key management scheme of wireless sensor network, i.e. KDC-based group key management mechanisms and predis- tribution mechanism based group key management scheme for a detailed analysis and research. Based on research and analysis of existing schemes,the paper presents an group key management scheme whose basic schemes are based on the ideas proposed by Blundo appeared in the paper“Polynomial based key predistribution scheme”.The phase of key distribution utilizes shared polynomial and symmetric encryption system to achieve the group key’s distribution and management, and based on it,the paper also gives a comprehensive scheme to address the problem of group key update upon adding and deleting nodes. The analysis shows it can achieve forward and backward security; meanwhile it has a great advantage on storage overhead, communication overhead and computational overhead.To make the group key management scheme more resistances against collusion, the paper also propose an improved scheme which bases on the idea of secret sharing: when a node is captured, polynomial share of each member should be updated before updating the group key, in order to reduce the workload of the cluster head,the base station is responsible for updating the polynomial share of each member and furthermore the cluster head employ Lagrange algorithm to update the polynomial used for key distribution with cooperating with a certain number of nodes. Security analysis shows that this scheme improves the capbility of collusion of group key management scheme.