The Keys Distribution Algorithms In WSN And Their Applications In Secure Routing Protocols

Because wireless sensor network(WSN) has large-scale of nodes, limted hardware capability, complexity of working environment and other constrains, the security of WSN is challenged by many issues. This thesis focus on the research of keys distribution and routing security protocols in WSN aiming to desing new and more secure algorithms and protocols.The characteristics of architecture, the security requirements, the common routing attacks and counter measures for a WSN are outlined in this thesis. With a detailed introduction of classic routing protocols, this thesis analyzes and summarizes the efficiency and the security performance for some typical protocols.Further firstly, a combinatorial key distribution algorithm based on the reputation mechanism is proposed. All nodes in a WSN can be divided into different types like secure nodes, insecure nodes and blacklist nodes according to the repudiating values. Using different algorithms to combine the hypercube-based key distribution algorithm and the location based key distribution algorithm, this thesis proposes two new algorithms of key distribution. Secure nodes work in mode 1 with higher ability of connectivity and lower ability of resistance to capture while, at the same time, insecure nodes work in mode 2 with lower ability of connectivity and higher ability of resistance to capture. This thesis describes the setup phase, direct key establishment phase and path key establishment phase in detail. The simulation results show that, the connectivity, the average length path of key establishment and the resistance are dynamic. The more secure networks have higher connectivity and the efficiency of communication is improved. On the contrary, with more nodes captured, the network reduces its ability of connectivity and increases its ability of resistance.The original GAF protocol is compromised to spoofed routing attack, selective forwarding attack and sybil attack. To prevent the spoofed routing attack, the combination of the “hybrid keys managing mechanism based on the node’s reputation evaluation” and the GAF, and the encryption and the authentication operations for routing information is proposed. To against the selective forwarding attack, a new cluster election algorithm is designed. To defend the sybil attack, the one-way hash function is suggested to be used for information authentication to counteract the forgery node. The modified SGAF could be in certain of a solution for resisting the three attacks. The simulation results show that the energy increasing portion for a SGAG is 8.3% times of the GAF cost and thus is acceptable.