Biblio

Wireless Mesh Networks (WMNs) are being considered as most adequate for deployment in the Neighborhood Area Network (NAN) domain of the smart grid infrastructure because their features such as self-organizing, scalability and cost-efficiency complement the NAN requirements. To enhance the security of the WMNs, the key refreshment strategy for the Simultaneous Authentication of Equals (SAE) or the Efficient Mesh Security Association (EMSA) protocols is an efficient way to make the network more resilient against the cyber-attacks. However, a security vulnerability is discovered in the EMSA protocol when using the key refreshment strategy. The first message of the Mesh Key Holder Security Handshake (MKHSH) can be forged and replayed back in the next cycles of the key refreshment leading to a Denial of Service (DoS) attack. In this paper, a simple one-way hash function based scheme is proposed to prevent the unprotected message from being replayed together with an enhancement to the key refreshment scheme to improve the resilience of the MKHSH. The Protocol Composition Logic (PCL) is used to verify the logical correctness of the proposed scheme, while the Process Analysis Toolkit (PAT) is used to evaluate the security functionality against the malicious attacks.

Distributed mesh sensor networks provide cost-effective communications for deployment in various smart grid domains, such as home area networks (HAN), neighborhood area networks (NAN), and substation/plant-generation local area networks. This paper introduces a dynamically updating key distribution strategy to enhance mesh network security against cyber attack. The scheme has been applied to two security protocols known as simultaneous authentication of equals (SAE) and efficient mesh security association (EMSA). Since both protocols utilize 4-way handshaking, we propose a Merkle-tree based handshaking scheme, which is capable of improving the resiliency of the network in a situation where an intruder carries a denial of service attack. Finally, by developing a denial of service attack model, we can then evaluate the security of the proposed schemes against cyber attack, as well as network performance in terms of delay and overhead.

In the security protocols of Efficient Mesh Security Association(EMSA), the key updating strategy is an effective method to ensure the security of communication. For the existing strategy of periodic automatic key updating, the PTK(Pairwise Transit Key) is updated through the complex 4-way handshake to produce each time. Once the update frequency of the PTK is faster, it will have a greater impact on throughput and delay of the network. On this basis, we propose a new strategy of dynamic key updating to ensure the safety and performance of wireless mesh networks. In the new strategy, mesh point(MP) and mesh authenticator(MA) negotiate a random function at the initial certification, and use the PTK which is generated by the 4-way handshake as the initial seed. When the PTK updating cycle comes, both sides generate the new keys using the random function, which do not have to generate a new PTK by complex 4-way handshake. The analysis of performance compared with existing strategies showed that the dynamic key updating strategy proposed in this paper have a larger increase in delay and throughput of the network.