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Xue, Nan, Wu, Xiaofan, Gumussoy, Suat, Muenz, Ulrich, Mesanovic, Amer, Dong, Zerui, Bharati, Guna, Chakraborty, Sudipta, Electric, Hawaiian.  2021.  Dynamic Security Optimization for N-1 Secure Operation of Power Systems with 100% Non-Synchronous Generation: First experiences from Hawai'i Island. 2021 IEEE Power Energy Society General Meeting (PESGM). :1—5.

This paper presents some of our first experiences and findings in the ARPA-E project ReNew100, which is to develop an operator support system to enable stable operation of power system with 100% non-synchronous (NS) generation. The key to 100% NS system, as found in many recent studies, is to establish the grid frequency reference using grid-forming (GFM) inverters. In this paper, we demonstrate in Electro-Magnetic-Transient (EMT) simulations, based on Hawai'i big island system with 100% NS capacity, that a system can be operated stably with the help of GFM inverters and appropriate controller parameters for the inverters. The dynamic security optimization (DSO) is introduced for optimizing the inverter control parameters to improve stability of the system towards N-1 contingencies. DSO is verified for five critical N-1 contingencies of big island system identified by Hawaiian Electric. The simulation results show significant stability improvement from DSO. The results in this paper share some insight, and provide a promising solution for operating grid in general with high penetration or 100% of NS generation.

Li, Luo, Li, Wen, Li, Xing.  2021.  A Power Grid Planning Method Considering Dynamic Limit of Renewable Energy Security Constraints. 2021 IEEE 5th Conference on Energy Internet and Energy System Integration (EI2). :1101—1105.

This paper puts forward a dynamic reduction method of renewable energy based on N-1 safety standard of power system, which is suitable for high-voltage distribution network and can reduce the abandoned amount of renewable energy to an ideal level. On the basis of AC sensitivity coefficient, the optimization method of distribution factor suitable for single line or multi-line disconnection is proposed. Finally, taking an actual high-voltage distribution network in Germany as an example, the simulation results show that the proposed method can effectively limit the line load, and can greatly reduce the line load with less RES reduction.

Fattakhov, Ruslan, Loginov, Sergey.  2021.  Discrete-nonlinear Colpitts oscillator based communication security increasing of the OFDM systems. 2021 International Conference on Electrotechnical Complexes and Systems (ICOECS). :253—256.

This article reports results about the development of the algorithm that allows to increase the information security of OFDM communication system based on the discrete-nonlinear Colpitts system with dynamic chaos. Proposed system works on two layers: information and transport. In the first one, Arnold Transform was applied. The second one, transport level security was provided by QAM constellation mixing. Correlation coefficients, Shannon's entropy and peak-to-average power ratio (PAPR) were estimated.

Mukherjee, Sayak, Adetola, Veronica.  2021.  A Secure Learning Control Strategy via Dynamic Camouflaging for Unknown Dynamical Systems under Attacks. 2021 IEEE Conference on Control Technology and Applications (CCTA). :905—910.

This paper presents a secure reinforcement learning (RL) based control method for unknown linear time-invariant cyber-physical systems (CPSs) that are subjected to compositional attacks such as eavesdropping and covert attack. We consider the attack scenario where the attacker learns about the dynamic model during the exploration phase of the learning conducted by the designer to learn a linear quadratic regulator (LQR), and thereafter, use such information to conduct a covert attack on the dynamic system, which we refer to as doubly learning-based control and attack (DLCA) framework. We propose a dynamic camouflaging based attack-resilient reinforcement learning (ARRL) algorithm which can learn the desired optimal controller for the dynamic system, and at the same time, can inject sufficient misinformation in the estimation of system dynamics by the attacker. The algorithm is accompanied by theoretical guarantees and extensive numerical experiments on a consensus multi-agent system and on a benchmark power grid model.

Han, Weiheng, Cai, Weiwei, Zhang, Guangjia, Yu, Weiguo, Pan, Junjun, Xiang, Longyun, Ning, Tao.  2021.  Cyclic Verification Method of Security Control System Strategy Table Based on Constraint Conditions and Whole Process Dynamic Simulation. 2021 IEEE/IAS Industrial and Commercial Power System Asia (I CPS Asia). :698—703.

The correctness of security control system strategy is very important to ensure the stability of power system. Aiming at the problem that the current security control strategy verification method is not enough to match the increasingly complex large power grid, this paper proposes a cyclic verification method of security control system strategy table based on constraints and whole process dynamic simulation. Firstly, the method is improved based on the traditional security control strategy model to make the strategy model meet certain generalization ability; And on the basis of this model, the cyclic dynamic verification of the strategy table is realized based on the constraint conditions and the whole process dynamic simulation, which not only ensures the high accuracy of strategy verification for the security control strategy of complex large power grid, but also ensures that the power system is stable and controllable. Finally, based on a certain regional power system, the optimal verification of strategy table verification experiment is realized. The experimental results show that the average processing time of the proposed method is 10.32s, and it can effectively guarantee the controllability and stability of power grid.

Wang, Qibing, Du, Xin, Zhang, Kai, Pan, Junjun, Yu, Weiguo, Gao, Xiaoquan, Lin, Rihong.  2021.  Reliability Test Method of Power Grid Security Control System Based on BP Neural Network and Dynamic Group Simulation. 2021 IEEE/IAS Industrial and Commercial Power System Asia (I CPS Asia). :680—685.

Aiming at the problems of imperfect dynamic verification of power grid security and stability control strategy and high test cost, a reliability test method of power grid security control system based on BP neural network and dynamic group simulation is proposed. Firstly, the fault simulation results of real-time digital simulation system (RTDS) software are taken as the data source, and the dynamic test data are obtained with the help of the existing dispatching data network, wireless virtual private network, global positioning system and other communication resources; Secondly, the important test items are selected through the minimum redundancy maximum correlation algorithm, and the test items are used to form a feature set, and then the BP neural network model is used to predict the test results. Finally, the dynamic remote test platform is tested by the dynamic whole group simulation of the security and stability control system. Compared with the traditional test methods, the proposed method reduces the test cost by more than 50%. Experimental results show that the proposed method can effectively complete the reliability test of power grid security control system based on dynamic group simulation, and reduce the test cost.

Raab, Alexander, Mehlmann, Gert, Luther, Matthias, Sennewald, Tom, Schlegel, Steffen, Westermann, Dirk.  2021.  Steady-State and Dynamic Security Assessment for System Operation. 2021 International Conference on Smart Energy Systems and Technologies (SEST). :1—6.

This contribution provides the implementation of a holistic operational security assessment process for both steady-state security and dynamic stability. The merging of steady-state and dynamic security assessment as a sequential process is presented. A steady-state and dynamic modeling of a VSC-HVDC was performed including curative and stabilizing measures as remedial actions. The assessment process was validated by a case study on a modified version of the Nordic 32 system. Simulation results showed that measure selection based on purely steady-state contingency analysis can lead to loss of stability in time domain. A subsequent selection of measures on the basis of the dynamic security assessment was able to guarantee the operational security for the stationary N-1 scenario as well as the power system stability.

Gainutdinov, Ilyas, Loginov, Sergey.  2021.  Increasing information security of a communication system with OFDM based on a discrete-nonlinear Duffing system with dynamic chaos. 2021 International Conference on Electrotechnical Complexes and Systems (ICOECS). :249—252.

In this work, the algorithm of increasing the information security of a communication system with Orthogonal Frequency Division Multiplexing (OFDM) was achieved by using a discrete-nonlinear Duffing system with dynamic chaos. The main idea of increasing information security is based on scrambling input information on three levels. The first one is mixing up data order, the second is scrambling data values and the final is mixing symbols at the Quadrature Amplitude Modulation (QAM) plot constellation. Each level's activities were made with the use of pseudorandom numbers set, generated by the discrete-nonlinear Duffing system with dynamic chaos.

Wang, Lei, Manchester, Ian R., Trumpf, Jochen, Shi, Guodong.  2020.  Initial-Value Privacy of Linear Dynamical Systems. 2020 59th IEEE Conference on Decision and Control (CDC). :3108—3113.
This paper studies initial-value privacy problems of linear dynamical systems. We consider a standard linear time-invariant system with random process and measurement noises. For such a system, eavesdroppers having access to system output trajectories may infer the system initial states, leading to initial-value privacy risks. When a finite number of output trajectories are eavesdropped, we consider a requirement that any guess about the initial values can be plausibly denied. When an infinite number of output trajectories are eavesdropped, we consider a requirement that the initial values should not be uniquely recoverable. In view of these two privacy requirements, we define differential initial-value privacy and intrinsic initial-value privacy, respectively, for the system as metrics of privacy risks. First of all, we prove that the intrinsic initial-value privacy is equivalent to unobservability, while the differential initial-value privacy can be achieved for a privacy budget depending on an extended observability matrix of the system and the covariance of the noises. Next, the inherent network nature of the considered linear system is explored, where each individual state corresponds to a node and the state and output matrices induce interaction and sensing graphs, leading to a network system. Under this network system perspective, we allow the initial states at some nodes to be public, and investigate the resulting intrinsic initial- value privacy of each individual node. We establish necessary and sufficient conditions for such individual node initial-value privacy, and also prove that the intrinsic initial-value privacy of individual nodes is generically determined by the network structure.
Murguia, Carlos, Tabuada, Paulo.  2020.  Privacy Against Adversarial Classification in Cyber-Physical Systems. 2020 59th IEEE Conference on Decision and Control (CDC). :5483–5488.
For a class of Cyber-Physical Systems (CPSs), we address the problem of performing computations over the cloud without revealing private information about the structure and operation of the system. We model CPSs as a collection of input-output dynamical systems (the system operation modes). Depending on the mode the system is operating on, the output trajectory is generated by one of these systems in response to driving inputs. Output measurements and driving inputs are sent to the cloud for processing purposes. We capture this "processing" through some function (of the input-output trajectory) that we require the cloud to compute accurately - referred here as the trajectory utility. However, for privacy reasons, we would like to keep the mode private, i.e., we do not want the cloud to correctly identify what mode of the CPS produced a given trajectory. To this end, we distort trajectories before transmission and send the corrupted data to the cloud. We provide mathematical tools (based on output-regulation techniques) to properly design distorting mechanisms so that: 1) the original and distorted trajectories lead to the same utility; and the distorted data leads the cloud to misclassify the mode.
Ramasubramanian, Bhaskar, Niu, Luyao, Clark, Andrew, Bushnell, Linda, Poovendran, Radha.  2020.  Privacy-Preserving Resilience of Cyber-Physical Systems to Adversaries. 2020 59th IEEE Conference on Decision and Control (CDC). :3785–3792.

A cyber-physical system (CPS) is expected to be resilient to more than one type of adversary. In this paper, we consider a CPS that has to satisfy a linear temporal logic (LTL) objective in the presence of two kinds of adversaries. The first adversary has the ability to tamper with inputs to the CPS to influence satisfaction of the LTL objective. The interaction of the CPS with this adversary is modeled as a stochastic game. We synthesize a controller for the CPS to maximize the probability of satisfying the LTL objective under any policy of this adversary. The second adversary is an eavesdropper who can observe labeled trajectories of the CPS generated from the previous step. It could then use this information to launch other kinds of attacks. A labeled trajectory is a sequence of labels, where a label is associated to a state and is linked to the satisfaction of the LTL objective at that state. We use differential privacy to quantify the indistinguishability between states that are related to each other when the eavesdropper sees a labeled trajectory. Two trajectories of equal length will be differentially private if they are differentially private at each state along the respective trajectories. We use a skewed Kantorovich metric to compute distances between probability distributions over states resulting from actions chosen according to policies from related states in order to quantify differential privacy. Moreover, we do this in a manner that does not affect the satisfaction probability of the LTL objective. We validate our approach on a simulation of a UAV that has to satisfy an LTL objective in an adversarial environment.

Ramos, E. de Almeida, Filho, J. C. B., Reis, R..  2019.  Cryptography by Synchronization of Hopfield Neural Networks that Simulate Chaotic Signals Generated by the Human Body. 2019 17th IEEE International New Circuits and Systems Conference (NEWCAS). :1–4.

In this work, an asymmetric cryptography method for information security was developed, inspired by the fact that the human body generates chaotic signals, and these signals can be used to create sequences of random numbers. Encryption circuit was implemented in a Reconfigurable Hardware (FPGA). To encode and decode an image, the chaotic synchronization between two dynamic systems, such as Hopfield neural networks (HNNs), was used to simulate chaotic signals. The notion of Homotopy, an argument of topological nature, was used for the synchronization. The results show efficiency when compared to state of the art, in terms of image correlation, histogram analysis and hardware implementation.

Hale, Matthew, Jones, Austin, Leahy, Kevin.  2018.  Privacy in Feedback: The Differentially Private LQG. 2018 Annual American Control Conference (ACC). :3386–3391.
Information communicated within cyber-physical systems (CPSs) is often used in determining the physical states of such systems, and malicious adversaries may intercept these communications in order to infer future states of a CPS or its components. Accordingly, there arises a need to protect the state values of a system. Recently, the notion of differential privacy has been used to protect state trajectories in dynamical systems, and it is this notion of privacy that we use here to protect the state trajectories of CPSs. We incorporate a cloud computer to coordinate the agents comprising the CPSs of interest, and the cloud offers the ability to remotely coordinate many agents, rapidly perform computations, and broadcast the results, making it a natural fit for systems with many interacting agents or components. Striving for broad applicability, we solve infinite-horizon linear-quadratic-regulator (LQR) problems, and each agent protects its own state trajectory by adding noise to its states before they are sent to the cloud. The cloud then uses these state values to generate optimal inputs for the agents. As a result, private data are fed into feedback loops at each iteration, and each noisy term affects every future state of every agent. In this paper, we show that the differentially private LQR problem can be related to the well-studied linear-quadratic-Gaussian (LQG) problem, and we provide bounds on how agents' privacy requirements affect the cloud's ability to generate optimal feedback control values for the agents. These results are illustrated in numerical simulations.
de Almeida Ramos, Elias, Filho, João Carlos Britto, Reis, Ricardo.  2019.  Cryptography by Synchronization of Hopfield Neural Networks that Simulate Chaotic Signals Generated by the Human Body. 2019 17th IEEE International New Circuits and Systems Conference (NEWCAS). :1–4.
In this work, an asymmetric cryptography method for information security was developed, inspired by the fact that the human body generates chaotic signals, and these signals can be used to create sequences of random numbers. Encryption circuit was implemented in a Reconfigurable Hardware (FPGA). To encode and decode an image, the chaotic synchronization between two dynamic systems, such as Hopfield neural networks (HNNs), was used to simulate chaotic signals. The notion of Homotopy, an argument of topological nature, was used for the synchronization. The results show efficiency when compared to state of the art, in terms of image correlation, histogram analysis and hardware implementation.
Wang, Manxi, Liu, Bingjie, Xu, Haitao.  2019.  Resource Allocation for Threat Defense in Cyber-security IoT system. 2019 28th Wireless and Optical Communications Conference (WOCC). :1—3.
In this paper, we design a model for resource allocation in IoT system considering the cyber security, to achieve optimal resource allocation when defend the attack and threat. The resource allocation problem is constructed as a dynamic game, where the threat level is the state and the defend cost is the objective function. Open loop solution and feedback solutions are both given to the defender as the optimal control variables under different solutions situations. The optimal allocated resource and the optimal threat level for the defender is simulated through the numerical simulations.
Chen, Jianfeng, Liu, Jie, Sun, Zhi, Li, Chunlin, Hu, Chunhui.  2019.  An Intelligent Cyberspace Defense Architecture Based on Elastic Resource Infrastructure and Dynamic Container Orchestration. 2019 International Conference on Networking and Network Applications (NaNA). :235–240.

The borderless, dynamic, high dimensional and virtual natures of cyberspace have brought unprecedented hard situation for defenders. To fight uncertain challenges in versatile cyberspace, a security framework based on the cloud computing platform that facilitates containerization technology to create a security capability pool to generate and distribute security payload according to system needs. Composed by four subsystems of the security decision center, the image and container library, the decision rule base and the security event database, this framework distills structured knowledge from aggregated security events and then deliver security load to the managed network or terminal nodes directed by the decision center. By introducing such unified and standardized top-level security framework that is decomposable, combinable and configurable in a service-oriented manner, it could offer flexibility and effectiveness in reconstructing security resource allocation and usage to reach higher efficiency.

Goncharov, Nikita, Dushkin, Alexander, Goncharov, Igor.  2019.  Mathematical Modeling of the Security Management Process of an Information System in Conditions of Unauthorized External Influences. 2019 1st International Conference on Control Systems, Mathematical Modelling, Automation and Energy Efficiency (SUMMA). :77–82.

In this paper, we consider one of the approaches to the study of the characteristics of an information system that is under the influence of various factors, and their management using neural networks and wavelet transforms based on determining the relationship between the modified state of the information system and the possibility of dynamic analysis of effects. At the same time, the process of influencing the information system includes the following components: impact on the components providing the functions of the information system; determination of the result of exposure; analysis of the result of exposure; response to the result of exposure. As an input signal, the characteristics of the means that affect are taken. The system includes an adaptive response unit, the input of which receives signals about the prerequisites for changes, and at the output, this unit generates signals for the inclusion of appropriate means to eliminate or compensate for these prerequisites or directly the changes in the information system.

Jalilian, Maisam, Ahmadi, Arash, Ahmadi, Majid.  2018.  Hardware Implementation of A Chaotic Pseudo Random Number Generator Based on 3D Chaotic System without Equilibrium. 2018 25th IEEE International Conference on Electronics, Circuits and Systems (ICECS). :741–744.
Deterministic chaotic systems have been studied and developed in various fields of research. Dynamical systems with chaotic dynamics have different applications in communication, security and computation. Chaotic behaviors can be created by even simple nonlinear systems which can be implemented on low-cost hardware platforms. This paper presents a high-speed and low-cost hardware of three-dimensional chaotic flows without equilibrium. The proposed chaotic hardware is able to reproduce the main mechanism and dynamical behavior of the 3D chaotic flows observed in simulation, then a Chaotic Pseudo Random Number Generator is designed based on a 3D chaotic system. The proposed hardware is implemented with low computational overhead on an FPGA board, as a proof of concept. This low-cost chaotic hardware can be utilized in embedded and lightweight systems for a variety of chaotic based digital systems such as digital communication systems, and cryptography systems based on chaos theory for Security and IoT applications.
Mili, S., Nguyen, N., Chelouah, R..  2018.  Attack Modeling and Verification for Connected System Security. 2018 13th Annual Conference on System of Systems Engineering (SoSE). :157–162.

In the development process of critical systems, one of the main challenges is to provide early system validation and verification against vulnerabilities in order to reduce cost caused by late error detection. We propose in this paper an approach that, firstly allows formally describe system security specifications, thanks to our suggested extended attack tree. Secondly, static and dynamic system modeling by using a SysML connectivity profile to model error propagation is introduced. Finally, a model checker has been used in order to validate system specifications.

Enoch, S. Yusuf, Hong, J. B., Kim, D. S..  2018.  Time Independent Security Analysis for Dynamic Networks Using Graphical Security Models. 2018 17th IEEE International Conference On Trust, Security And Privacy In Computing And Communications/ 12th IEEE International Conference On Big Data Science And Engineering (TrustCom/BigDataSE). :588–595.

It is technically challenging to conduct a security analysis of a dynamic network, due to the lack of methods and techniques to capture different security postures as the network changes. Graphical Security Models (e.g., Attack Graph) are used to assess the security of network systems, but it typically captures a snapshot of a network state to carry out the security analysis. To address this issue, we propose a new Graphical Security Model named Time-independent Hierarchical Attack Representation Model (Ti-HARM) that captures security of multiple network states by taking into account the time duration of each network state and the visibility of network components (e.g., hosts, edges) in each state. By incorporating the changes, we can analyse the security of dynamic networks taking into account all the threats appearing in different network states. Our experimental results show that the Ti-HARM can effectively capture and assess the security of dynamic networks which were not possible using existing graphical security models.

Naik, N., Shang, C., Shen, Q., Jenkins, P..  2018.  Vigilant Dynamic Honeypot Assisted by Dynamic Fuzzy Rule Interpolation. 2018 IEEE Symposium Series on Computational Intelligence (SSCI). :1731–1738.

Dynamic Fuzzy Rule Interpolation (D-FRI) offers a dynamic rule base for fuzzy systems which is especially useful for systems with changing requirements and limited prior knowledge. This suggests a possible application of D-FRI in the area of network security due to the volatility of the traffic. A honeypot is a valuable tool in the field of network security for baiting attackers and collecting their information. However, typically designed with fewer resources they are not considered as a primary security tool for use in network security. Consequently, such honeypots can be vulnerable to many security attacks. One such attack is a spoofing attack which can cause severe damage to the honeypot, making it inefficient. This paper presents a vigilant dynamic honeypot based on the D-FRI approach for use in predicting and alerting of spoofing attacks on the honeypot. First, it proposes a technique for spoofing attack identification based on the analysis of simulated attack data. Then, the paper employs the identification technique to develop a D-FRI based vigilant dynamic honeypot, allowing the honeypot to predict and alert that a spoofing attack is taking place in the absence of matching rules. The resulting system is capable of learning and maintaining a dynamic rule base for more accurate identification of potential spoofing attacks with respect to the changing traffic conditions of the network.

Borra, V. S., Debnath, K..  2018.  Dynamic programming for solving unit commitment and security problems in microgrid systems. 2018 IEEE International Conference on Innovative Research and Development (ICIRD). :1–6.

In order to meet the demand of electrical energy by consumers, utilities have to maintain the security of the system. This paper presents a design of the Microgrid Central Energy Management System (MCEMS). It will plan operation of the system one-day advance. The MCEMS will adjust itself during operation if a fault occurs anywhere in the generation system. The proposed approach uses Dynamic Programming (DP) algorithm solves the Unit Commitment (UC) problem and at the same time enhances the security of power system. A case study is performed with ten subsystems. The DP is used to manage the operation of the subsystems and determines the UC on the situation demands. Faults are applied to the system and the DP corrects the UC problem with appropriate power sources to maintain reliability supply. The MATLAB software has been used to simulate the operation of the system.

Shen, W., Liu, Y., Wu, Q., Tian, Y., Liu, Y., Peng, H..  2018.  Application of Dynamic Security Technology Architecture for Advanced Directional Attacks in Power System Information Security. 2018 International Conference on Power System Technology (POWERCON). :3042–3047.

In view of the increasingly severe network security situation of power information system, this paper draws on the experience of construction of security technology system at home and abroad, with the continuous monitoring and analysis as the core, covering the closed-loop management of defense, detection, response and prediction security as the starting point, Based on the existing defense-based static security protection architecture, a dynamic security technology architecture based on detection and response is established. Compared with the traditional PDR architecture, the architecture adds security threat prediction, strengthens behavior-based detection, and further explains the concept of dynamic defense, so that it can adapt to changes in the grid IT infrastructure and business application systems. A unified security strategy can be formed to deal with more secretive and professional advanced attacks in the future. The architecture emphasizes that network security is a cyclical confrontation process. Enterprise network security thinking should change from the past “emergency response” to “continuous response”, real-time dynamic analysis of security threats, and automatically adapt to changing networks and threat environments, and Constantly optimize its own security defense mechanism, thus effectively solving the problem of the comprehensive technology transformation and upgrading of the security technology system from the traditional passive defense to the active sensing, from the simple defense to the active confrontation, and from the independent protection to the intelligence-driven. At the same time, the paper also gives the technical evolution route of the architecture, which provides a planning basis and a landing method for the continuous fulfillment of the new requirements of the security of the power information system during the 13th Five-Year Plan period.

Yagoub, Mohammed Amine, Laouid, Abdelkader, Kazar, Okba, Bounceur, Ahcène, Euler, Reinhardt, AlShaikh, Muath.  2018.  An Adaptive and Efficient Fully Homomorphic Encryption Technique. Proceedings of the 2Nd International Conference on Future Networks and Distributed Systems. :35:1–35:6.

The huge amount of generated data offers special advantages mainly in dynamic and scalable systems. In fact, the data generator entities need to share the generated data with each other which leads to the use of cloud services. A cloud server is considered as an untrusted entity that offers many advantages such as large storing space, computation speed... etc. Hence, there is a need to cope with how to protect the stored data in the cloud server by proposing adaptive solutions. The main objective is how to provide an encryption scheme allowing the user to maintains some functions such as addition, multiplication and to preserve the order on the encrypted cloud data. Many algorithms and techniques are designed to manipulate the stored encrypted cloud data. This paper presents an adaptive and efficient fully homomorphic encryption technique to protect the user's data stored in the cloud, where the cloud server executes simple operations.

Chen, Huashan, Cho, Jin-Hee, Xu, Shouhuai.  2018.  Quantifying the Security Effectiveness of Firewalls and DMZs. Proceedings of the 5th Annual Symposium and Bootcamp on Hot Topics in the Science of Security. :9:1–9:11.

Firewalls and Demilitarized Zones (DMZs) are two mechanisms that have been widely employed to secure enterprise networks. Despite this, their security effectiveness has not been systematically quantified. In this paper, we make a first step towards filling this void by presenting a representational framework for investigating their security effectiveness in protecting enterprise networks. Through simulation experiments, we draw useful insights into the security effectiveness of firewalls and DMZs. To the best of our knowledge, these insights were not reported in the literature until now.