Research On Network Topology Security Of Complex Information Systems Based On Complex Networks

Recently the rapid development of computer technology and network technology makes information systems assume an increasingly important role in human society. People’s ever growing needs for information systems makes traditional information systems gradually transformed to complex information systems. Complex information systems have been integrated into all aspects of social life, and its security becomes particularly important. Therefore, improving the security of complex information systems has become a common goal of researchers and administrators. The security of complex information systems is closely related to the security of network topology. As a result, the research on the security issues from the perspective of network topology is one of the most important research fields in complex information system security.Complex information system has large scale and high complexity, and its network topology forms a large-scale network, showing the complex network characteristics. This thesis analyzes the network topology security of complex information systems based on complex networks theory, studies on the security risk propagation characteristics in complex information system network topology and the cascading failures behavior characteristics in complex information system network topology. And a series of models and novel methods are proposed. Then this work studies the influence of various network topology factors on the dynamics in complex networks, and on this basis, the network topology security of complex information systems is analyzed. The main innovation points in this paper are as follows:(1) The model of Complex Information System based on the relevance of physical level and logical level is proposed and the security threats and security risk characteristics of Complex Information System are analyzed. Current research on information systems are usually launched from physical level and logical level respectively, without establishing the relationship between each other. As the system evolved into a complex information system, the complexity makes the linear or reticular relationships of two levels can not be accurately established. This paper presents a complex information system model based on the relevance of physical level and logical level, and can describe the relationship between physical devices and businesses. Complex Information System model proposed in this paper makes up for the current lack of Complex Information System model. And security risk characteristics of Complex Information System proposed in this article is instructive on the network topology security research of complex information systems.(2) Analysis of the network topology static security of complex information system based on security risk propagation. Model of complex information system security risk propagation is proposed in this paper based on cellular automata, and the probabilistic behaviors of security risk propagation in complex information systems are investigated by running the proposed model on four kinds of networks respectively. By researching on the propagation threshold of security risks and the evolutionary trends of security risk propagation, the key factors affecting the security risk propagation are analyzed in this paper. And the comprehensive analysis method of network topology static security is proposed, providing guidance for the control of security risk propagation in complex information systems and for the research on network topology static security of complex information systems.(3) Analysis of the network topology dynamic security of complex information system based on cascading failures. Model of cascading failures in complex networks with network efficiency and node failure probability, model of cascading failures with network efficiency and edge failure probability, and model of cascading failures with large load value are proposed in this paper and the cascading dynamics are investigated by running the proposed models on four kinds of networks respectively. The new concept of the efficiency of networks is defined. And the effects of the parameters on the network efficiency and failure rate are investigated. The comprehensive analysis method of network topology dynamic security is proposed. All these results can help analyze the cascading dynamics in complex networks, and can provide the guidance for the control of cascading failures and being protected against them in real-life complex networks. And the work can provide guidance for the research on network topology dynamics security of complex information systems as well.(4) Research on the network topology security of complex information systems with security measures. The main security measure against static network topology security issues is to establish security risk immune mechanisms, and the main security measure against dynamic network topology security issues is to establish emergency recovery mechanisms. Models of complex information system security risk propagation with immune mechanisms and models of cascading failures in complex networks with an emergency recovery mechanism are proposed. By researching on the evolutionary trends of security risk propagation, the relationship between the heterogeneity of degree distribution and the effect of the immune mechanism on controlling security risk propagation is pointed out. And the research results on these models demonstrate that the increasing of the emergency recovery probability reduces the network efficiency reducing speed and the failure rate growing speed, and also improves the resilience of the network. The work in this paper also analyzes the protective effects of the security measures, and can provide guidance for the research on network topology security of complex information systems with security measures.