Research On Modeling And Optimization Of System Attack-defense Game Based On Reliability

The system reliability is an important foundation for improving the quality of Chinese products and services.The external operation environment of systems is more complex due to the development of new technology.In recent years,some serious system security incidents such as the illegal intrusion of the Israel's State Grid in 2017 and the global outbreak of “Wannacry” ransomware virus in 2017 show that the security and the reliability of a system is in the risk of external intentional attacks.Therefore,it is of great practical significance to study the defense of systems against external intentional attacks in order to enhance the security and reliability of systems.The external intentional attack is usually strategic and the intentional attacker always chooses the most harmful strategies to maximize the destruction of the system.It is challenging to defend the system against intentional attackers since they are strategic.This thesis studies the defense of systems against external intentional attacks.Different cases are included such as the defense of a system against an attacker with multiple and intelligence attack measures,the defense of a system against sequential unintentional and intentional attacks and multiple defenders defend a system against multiple attackers.The problem is modelled as a defense-attack game.The joint optimization problem of defense resource allocation is solved and the optimal defense strategy is studied.This thesis also applies the defense-attack game modelling and optimization theory to defend the distributed data storage system and the energy system.The main research contents include the following aspects:First,the modelling and optimization of the defense-attack game of defending a system against an attacker with multiple and intelligence attack measures are studied.In order to defend a system against an attacker with multiple and intelligence attack measures,this thesis proposes to apply the defense measures such as the overarching protection,the individual protection,redundant and the disinformation to defend the system.According to different system structures,the defense-attack games are modelled respectively.The joint optimization problem of defense resource allocation is solved and the optimal defense strategy is studied.Second,the modelling and optimization of the defense-attack game of defending a system against sequential unintentional and intentional attacks are studied.The defense-attack games are modelled respectively when the intentional attack occurs first and when the unintentional attack occurs first.The corresponding optimal defense strategies are solved.Moreover,the defense-attack game is modelled when the defender can provide supplemental protection after the first attack.The efficient of providing supplemental protection is analyzed in different scenarios.Third,the modelling and optimization of the defense-attack game between defenders and attackers are studied.In the defense-attack game,the risk attitudes of all the defenders and all the attackers are incorporated.The defense-attack game using the static game model and the dynamic game model are analyzed.In the static model,the attackers move simultaneously,and the attackers move sequentially in the dynamic model.The optimal defense resources allocation of each defender and the optimal offensive resources allocation of each attacker are solved.Moreover,the effect of the attackers' sequence of move on the optimal defense strategy is also studied.Finally,the defense-attack game modelling and optimization theory are applied to defend practical systems.In addition to theoretical research,this thesis also applies the defense-attack game modelling and optimization theory to defend the distributed data storage system and the energy system.For the distributed data storage system,the defense-attack game is modelled and the joint optimization of defense resources allocation and the computer protection is solved.Some management insights are gained for the decision maker.For the energy system,two different evaluation criterions including the system reliability and the expected system loss are considered when modelling the defense-attack game.The joint optimization of system configuration and defense resources allocation is solved to enhance the system reliability or reduce the expected system loss without additional cost.