A Key Management Protocol for Multiphase Hierarchical Wireless Sensor Networks

The security of Wireless Sensor Networks (WSNs) has a direct reliance on secure and efficient key management. This leaves key management as a fundamental research topic in the field of WSNs security. Among the proposed key management schemes for WSNs security, LEAP (Localized Encryption and Authentication Protocol) has been regarded as an efficient protocol over the last years. LEAP supports the establishment of four types of keys. The security of these keys is under the assumption that the initial deployment phase is secure and the initial key is erased from sensor nodes after the initialization phase. However, the initial key is used again for node addition after the initialization phase whereas the new node can be compromised before erasing the key. A time-based key management scheme rethought the security of LEAP. We show the deficiency of the time-based key management scheme and proposed a key management scheme for multi-phase WSNs in this paper. The proposed scheme disperses the damage resulting from the disclosure of the initial key. We show it has better resilience and higher key connectivity probability through the analysis.