Freshness Consideration of Hierarchical Key Agreement Protocol in WSNs

Wireless sensor networks (WSNs) are often deployed in potentially adverse or even hostile environment so that there are concerns on security issues in these WSNs. Sensor nodes with resource-constrained make security applications a challenging problem. Key agreement is a fundamental security service in WSNs, which enables sensor nodes to communicate securely with each other using cryptographic techniques. However, due to the resource constraints on sensor nodes, it is infeasible to use traditional key management techniques such as public key cryptography and key distribution center. Recently, Kim proposed two efficient and noninteractive hierarchical key agreements in WSNs, which have good properties including noninteractive, hierarchical, resilient, etc. However, Kim’s protocols do not support freshness of the established session key that key agreement protocol should supports. Thereby, we propose two freshness preserving hierarchical key agreement protocols over the hierarchical WSNs, named as HKAP_FP. Our two HKAP_FPs inherit advantages from Kim’s protocols and well suited to the hierarchical WSNs.