Research On Security Risk Assessment Based Cognitive Technology In Space Information Networks

Space information networks is a highly open distributed wireless network. It can be used in many applications and it is very important for national economy and military applications. Space information networks has many characteristics, such as node diversity, topology change and large, but these inherent characteristics make it vulnerable to security risks. Comparing to traditional terrestrial networks, it is more vulnerable to its environment and security threats. At the same time, the space information networks play an important role in the national economy and military applications, it puts forward high demands on network security. Risk assessment can predict and diagnose the network security threats, provide decision-making basis for security policy and counter measures. It become an important part of network security protection system.In order to improve the security of space information networks, a model based on cognitive of space information network security risk assessment is proposed and this model consists of multi-domain cognition module and safety risk assessment module. Cognitive wireless network technology is used in multi-domain cognition module. The network architecture and node cognitive structure were designed to access to network information. Then it dealt with the raw data and used the extracted information to the risk assessment module. Security risk assessment module compute nodes, subnets and the whole network risk. By analyzing the severity, priority and asset of the attack, the threat level is assessed and node value at risk is acquired. Subnet security risk assessment using hidden markov model which is based on network nodes’ connection, it not only considered the attacks on the immediate impact of each node, but also considered the indirect risks from the relationship between the nodes. Finally, the whole network central node united asset and risk of subnet to get overall network risk.In this thesis, using NS2 simulation platform simulate the algorithm. Simulation analysis showed that the node, subnet and the entire network security risk assessment method is applicable to space information networks. the algorithm can accurately assessed the network security risk condition.