Key Management Protocol for Wireless Sensor Networks

Key management is a prerequisite for many security services such as au- thentication and encryption. In wireless sensor networks (WSNs), key management becomes more crucial because they can be deployed in hos- tile environments. The unique challenges of wireless sensor networks and constraints in power, processing and storage, impede the use of traditional security mechanisms, such as public key cryptography, to be applied in WSNs. Therefore, symmetric key cryptography with key pre-distribution is more suitable for large-scale WSNs. However, designing an efficient key management protocol for WSNs is a difficult task. To be robust and adaptable to many applications, the key management protocol should also support both pair-wise and group wise communication. Many previous works have focused on developing efficient pair-wise key management protocols in WSNs. Very few works, however, have addressed the pair- wise and group wise key management together using same pre-distributed secret. Moreover, key revocation, key material refresh, and new node addi- tion issues have received less attention. In this paper, we propose a new key management protocol that provides support for both pair-wise and group wise key management with the same pre-distributed secrets. The purpose of the protocol is to minimize key management redesign effort for different applications. Our protocol is very efficient in terms of communication and storage overhead. It can update both the keys to support key revocation, key refresh and new node addition.