A New Efficient Key Management Protocol for Wireless Sensor and Actor Networks

Yunho Lee , Soojin Lee Department of Computer & Information Science, Korea National Defense University, Seoul, South Korea

Abstract—Research on sensor networks has become much more active and is currently being applied to many different fields. However since sensor networks are limited to only collecting and reporting information regarding a certain event, and requires human intervention with that given information, it is often difficult to react to an event or situation immediately and proactively. To overcome this kind of limitation, Wireless Sensor and Actor Networks (WSANs) with immediate-response actor nodes have been proposed which adds greater mobility and activity to the existing sensor networks. Although WSANs share many common grounds with sensor networks, it is difficult to apply existing security technologies due to the fact that WSANs contain actor nodes that are resource-independent and mobile. Therefore, this research seeks to demonstrate ways to provide security, integrity, and authentication services for WSAN’s secure operation, by separating networks into hierarchical structure by each node’s abilities and provides different encryption key-based secure protocols for each level of hierarchy: Pair-wise key, node key, and region key for sensor levels, and public key for actor Keywords ; Wireless Sensor and Actor Network(WSAN), Key management Protocol I. INTRODUCTION
Sensor networks, which have gained interests with the advancement of wireless communication technologies and embedded computing, are being widely adapted into many applications and many active researches on related subject are being carried out. A sensor network utilizes multitudes of sensor nodes within or neighboring the area of event to collect integrate, process, and relay the information regarding the event through sink node. Due to this inherent structure, this system requires additional special efforts in order to enable immediate and on-time response to the events based on those processed information.
WSANs(Wireless Sensor and Actor Networks) are proposed to overcome the limitations of traditional sensor networks. It includes mobile and resource-efficient actors within the network and enables these actors to respond appropriately based on the information collected by sensor nodes. This is in fact a very useful and applicable type of network that can be used in applications such as Forrest-fire monitoring, home intrusion prevention or military surveillance and operations [1]. WSANs share many similarities with sensor networks as they are networks without infrastructure and they use wireless communication technologies. Therefore WSANs require many existing applied technologies in their deployment. Unlike traditional sensor networks whose nodes share the same authority and power, actor-based WSANs require a different approach in implementing these technologies. Especially, WSN only consists of sensor nodes which are resource dependent. And the network structure of WSNs is very simple. Considering both the resource limitation of sensor nodes and the structural simplicity of WSNs, most key management protocols have researched by symmetric encryption approach. But WSANs have not only sensor nodes but also actor nodes which are resource independent. Thus, the structural feature of WSANs has to be considered. Due to the facts, existing protocols for the WSNs are not suitable for WSANs. Therefore, in this paper, we propose a new efficient key management protocol for the WSAN. The major contributions are summarized as follows:
a) Our proposed protocol splits the WSAN into two layers, the upper (sink-actor) layer and the lower (actor- sensor) layer. In the lower layer, we use symmetric approach by adopting the key management concept of the LEAP. But, especially to achieve the energy efficiency, we reduce the number of the key and simplify the procedure of the key establishment, and then reduce the amount of memory required and communication cost comparing with LEAP. In the upper layer, we use asymmetric encryption mechanism to provide the high degree of security.
b) When replacing the existing actor node with the new actor node, it is not efficient that again establish the node key and region key between the new actor node and sensor nodes. So we employ the binding table in the actor and sink node.
This paper examines the communication structure and security requirement for WSANs, and proposes a new efficient key-management protocol to ensure security in routing, transmission, and authentication of data. Performance analysis of the proposed protocol will follow and demonstrate its security and efficiency. The remainder of this paper is organized as follows. S

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