Towards a science of security games

Abstract. Security is a critical concern around the world. In many domains from counter-terrorism to sustainability, limited security resources prevent complete security coverage at all times. Instead, these limited resources must be scheduled (or allocated or deployed), while simultaneously taking into account the impor-tance of different targets, the responses of the adversaries to the security posture, and the potential uncertainties in adversary payoffs and observations, etc. Com-putational game theory can help generate such security schedules. Indeed, casting the problem as a Stackelberg game, we have developed new algorithms that are now deployed over multiple years in multiple applications for scheduling of secu-rity resources. These applications are leading to real-world use-inspired research in the emerging research area of “security games”. The research challenges posed by these applications include scaling up security games to real-world sized prob-lems, handling multiple types of uncertainty, and dealing with bounded rationality of human adversaries.

Reinforcement Learning and Game Theory for Smart Grid Security

This dissertation focuses on one of the most critical and complicated challenges facing electric power transmission and distribution systems which is their vulnerability against failure and attacks. Large scale power outages in Australia (2016), Ukraine (2015), India (2013), Nigeria (2018), and the United States (2011, 2003) have demonstrated the vulnerability of power grids to cyber and physical attacks and failures. These incidents clearly indicate the necessity of extensive research efforts to protect the power system from external intrusion and to reduce the damages from post-attack effects. We analyze the vulnerability of smart power grids to cyber and physical attacks and failures, design different gametheoretic approaches to identify the critical components vulnerable to attack and propose their associated defense strategy, and utilizes machine learning techniques to solve the game-theoretic problems in adversarial and collaborative adversarial power grid environment. Our contributions can be divided into three major parts:Vulnerability identification: Power grid outages have disastrous impacts on almost every aspect of modern life. Despite their inevitability, the effects of failures on power grids’ performance can be limited if the system operator can predict and identify the vulnerable elements of power grids. To enable these capabilities we study machine learning algorithms to identify critical power system elements adopting a cascaded failure simulator as a threat and attack model. We use generation loss, time to reach a certain percentage of line outage/generation loss, number of line outages, etc. as evaluation metrics to evaluate the consequences of threat and attacks on the smart power grid.Adversarial gaming in power system: With the advancement of the technologies, the smart attackers are deploying different techniques to supersede the existing protection scheme. In order to defend the power grid from these smart attackers, we introduce an adversarial gaming environment using machine learning techniques which is capable of replicating the complex interaction between the attacker and the power system operators. The numerical results show that a learned defender successfully narrows down the attackers’ attack window and reduce damages. The results also show that considering some crucial factors, the players can independently execute actions without detailed information about each other.Deep learning for adversarial gaming: The learning and gaming techniques to identify vulnerable components in the power grid become computationally expensive for large scale power systems. The power system operator needs to have the advanced skills to deal with the large dimensionality of the problem. In order to aid the power system operator in finding and analyzing vulnerability for large scale power systems, we study a deep learning technique for adversary game which is capable of dealing with high dimensional power system state space with less computational time and increased computational efficiency. Overall, the results provided in this dissertation advance power grids’ resilience and security by providing a better understanding of the systems’ vulnerability and by developing efficient algorithms to identify vulnerable components and appropriate defensive strategies to reduce the damages of the attack

Approaches to the Security Analysis of Power Systems: Defence Strategies Against Malicious Threats

This report is intended to provide a conceptual framework for assessing the security risk to power systems assets and operations related to malicious attacks. The problem is analysed with reference to all the actors involved and the possible targets. The specific nature of the malicious attacks is discussed and representations in terms of strategic interaction are proposed. Models based on Game Theory and Multi Agent Systems techniques specifically developed for the representation of malicious attacks against power systems are presented and illustrated with reference to applications to small-scale test systems.JRC.G.6-Sensors, radar technologies and cybersecurit

A Framework for the Game-theoretic Analysis of Censorship Resistance

We present a game-theoretic analysis of optimal solutions for interactions between censors and censorship resistance systems (CRSs) by focusing on the data channel used by the CRS to smuggle clients’ data past the censors. This analysis leverages the inherent errors (false positives and negatives) made by the censor when trying to classify traffic as either non-circumvention traffic or as CRS traffic, as well as the underlying rate of CRS traffic. We identify Nash equilibrium solutions for several simple censorship scenarios and then extend those findings to more complex scenarios where we find that the deployment of a censorship apparatus does not qualitatively change the equilibrium solutions, but rather only affects the amount of traffic a CRS can support before being blocked. By leveraging these findings, we describe a general framework for exploring and identifying optimal strategies for the censorship circumventor, in order to maximize the amount of CRS traffic not blocked by the censor. We use this framework to analyze several scenarios with multiple data-channel protocols used as cover for the CRS. We show that it is possible to gain insights through this framework even without perfect knowledge of the censor’s (secret) values for the parameters in their utility function

Modelling Telecommunications Operators and Adversaries using Game Theory

Telecommunications systems being inherently distributed and collaborative in nature present a plurality of attack surfaces to malicious entities and hence vulnerable to many potential attacks even indirectly demanding a need in prioritising security. The choice of security implementations depends upon the currently understood threats, future possible threat vectors, and the dependencies between systems. Executing these choices while contemplating the financial aspects is exceptionally difficult. It is thus critical to have a perceptible decision support framework for better security decision-making. This thesis studies the strategic nature of the interaction between the Telecoms operators and attackers utilising game theory to understand their strategic decision-making characteristics strengthening security decisions. To understand the security investment decision-making criteria of operators, this thesis utilises static security investment games. Through these games, we study the effects of security investment decision of an operator on other operators' behaviour. We determine conditions supporting the security investment decisions and propose strategic recommendations supplementing the dependency conditions. We then study attackers' behaviour considering them with strategic incentives in contrary to their strictly-bounded rationality in traditional game-theoretic modelling approaches. We utilise a behavioural approach and design a decision-flow model capturing the choices of attackers in the attack process. An outcome of this work is a generalised attack framework. Moreover, using this framework, we derive attack strategies optimising attackers' effort. Through this work, we are probing the foundations for drawing inferences about attackers' strategic characteristics from a cybersecurity perspective