Securing network access in wireless sensor networks

In wireless sensor networks, it is critical to restrict the network access only to eligible sensor nodes, while messages from outsiders will not be forwarded in the networks. In this paper, we present the design, implementation, and evaluation of a secure network access system for wireless sensor networks. This paper makes three contributions: First, it develops a network admission control subsystem using Elliptic Curve public key cryptosystem to add new sensor nodes into a sensor network. The admission control subsystem employs a polynomial-based weak authentication scheme to mitigate Denial of Service (DoS) attacks against the public key cryptographic operations. Second, it implements an interface in TinyOS to provide symmetric key cryptography using the hardware security support in IEEE 802.15.4 radio components (e.g., CC2420). The hardware security can satisfy both message authentication and timely delivery requirements in real-time applications. The third contribution is an implementation of a stateless group key update scheme to update a network-wide secret key in a sensor network. We implement all the proposed techniques on Imote2 sensor platform running TinyOS and conduct an evaluation through field experiments.