Cyber-Physical Systems Security—A Survey <s> B. Cyber Controls 1) ICS Controls: a) Encryption and key management: <s> Supervisory control and data-acquisition (SCADA) systems are control systems for many national infrastructures. In the past, SCADA systems were designed without security functionality because of the closed operating environment. However, the security of SCADA systems has become an issue with connection to open networks becoming more common. Any damage to the SCADA system can have a widespread negative effect to society. In this paper, we review constraints and security requirements for SCADA systems and then investigate whether the existing key-management protocols for the SCADA systems satisfy these requirements. Afterward, we propose an advanced key-management architecture fitted for secure SCADA communications. The contributions of our work are two-fold. First, our scheme supports both message broadcasting and secure communication. Second, by evenly spreading much of the total amount of computation across high power nodes (MTU or SUB-MTU), our protocol avoids any potential performance bottleneck of the system while keeping the burden on low power nodes (RTU) at minimal. <s> BIB001 </s> Cyber-Physical Systems Security—A Survey <s> B. Cyber Controls 1) ICS Controls: a) Encryption and key management: <s> Global electrical grids are verging on the largest technological transformation since the introduction of electricity into the home. The antiquated infrastructure that delivers power to our homes and businesses is being replaced with a collection of digital systems called the smart grid. This grid is the modernization of the existing electrical system that enhances customers' and utilities' ability to monitor, control, and predict energy use. <s> BIB002 </s> Cyber-Physical Systems Security—A Survey <s> B. Cyber Controls 1) ICS Controls: a) Encryption and key management: <s> SCADA systems run silently in the background of our power generation plants, manufacturing facilities, and many other critical infrastructure resources. Even though these SCADA systems are critical in nature, the IT community often poorly understands them. As a result, security of SCADA systems has been neglected, even though companies have improved their security posture to meet regulatory demands. This paper will explore some of the weaknesses in SCADA based system security and the effectiveness of current security techniques. In addition, new methods and tools will be proposed to augment SCADA system security strategies. <s> BIB003 </s> Cyber-Physical Systems Security—A Survey <s> B. Cyber Controls 1) ICS Controls: a) Encryption and key management: <s> Cyber security of Supervisory Control And Data Acquisition (SCADA) systems has become very important. SCADA systems are vital for operation and control of critical infrastructures, such as the electrical power system. Therefore, a number of standards and guidelines have been developed to support electric power utilities in their cyber security efforts. <s> BIB004 </s> Cyber-Physical Systems Security—A Survey <s> B. Cyber Controls 1) ICS Controls: a) Encryption and key management: <s> The purpose of this document is to provide guidance for securing industrial control systems (ICS), including supervisory control and data acquisition (SCADA) systems, distributed control systems (DCS), and other systems performing control functions. The document provides an overview of ICS and typical system topologies, identifies typical threats and vulnerabilities to these systems, and provides recommended security countermeasures to mitigate the associated risks. Because there are many different types of ICS with varying levels of potential risk and impact, the document provides a list of many different methods and techniques for securing ICS. The document should not be used purely as a checklist to secure a specific system. Readers are encouraged to perform a risk-based assessment on their systems and to tailor the recommended guidelines and solutions to meet their specific security, business and operational requirements. The scope of this document includes ICS that are typically used in the electric, water and wastewater, oil and natural gas, chemical, pharmaceutical, pulp and paper, food and beverage, and discrete manufacturing (automotive, aerospace, and durable goods) industries. <s> BIB005 </s> Cyber-Physical Systems Security—A Survey <s> B. Cyber Controls 1) ICS Controls: a) Encryption and key management: <s> Recent studies have revealed security vulnerabilities in implantable medical devices (IMDs). Security design for IMDs is complicated by the requirement that IMDs remain operable in an emergency when appropriate security credentials may be unavailable. In this paper, we introduce IMDGuard, a comprehensive security scheme for heart-related IMDs to fulfill this requirement. IMDGuard incorporates two techniques tailored to provide desirable protections for IMDs. One is an ECG based key establishment without prior shared secrets, and the other is an access control mechanism resilient to adversary spoofing attacks. The security and performance of IMDGuard are evaluated on our prototype implementation. <s> BIB006 </s> Cyber-Physical Systems Security—A Survey <s> B. Cyber Controls 1) ICS Controls: a) Encryption and key management: <s> Wireless communication has become an intrinsic part of modern implantable medical devices (IMDs). Recent work, however, has demonstrated that wireless connectivity can be exploited to compromise the confidentiality of IMDs' transmitted data or to send unauthorized commands to IMDs---even commands that cause the device to deliver an electric shock to the patient. The key challenge in addressing these attacks stems from the difficulty of modifying or replacing already-implanted IMDs. Thus, in this paper, we explore the feasibility of protecting an implantable device from such attacks without modifying the device itself. We present a physical-layer solution that delegates the security of an IMD to a personal base station called the shield. The shield uses a novel radio design that can act as a jammer-cum-receiver. This design allows it to jam the IMD's messages, preventing others from decoding them while being able to decode them itself. It also allows the shield to jam unauthorized commands---even those that try to alter the shield's own transmissions. We implement our design in a software radio and evaluate it with commercial IMDs. We find that it effectively provides confidentiality for private data and protects the IMD from unauthorized commands. <s> BIB007 </s> Cyber-Physical Systems Security—A Survey <s> B. Cyber Controls 1) ICS Controls: a) Encryption and key management: <s> Wearable and implantable medical devices are being increasingly deployed to improve diagnosis, monitoring, and therapy for a range of medical conditions. Unlike other classes of electronics and computing systems, security attacks on these devices have extreme consequences and must, therefore, be analyzed and prevented with utmost effort. Yet, very little work exists on this important topic and the security vulnerabilities of such systems are not well understood. We demonstrate security attacks that we have implemented in the laboratory on a popular glucose monitoring and insulin delivery system available on the market, and also propose defenses against such attacks. Continuous glucose monitoring and insulin delivery systems are becoming increasingly popular among patients with diabetes. These systems utilize wireless communication links, which are frequently utilized as a portal to launch security attacks. Our study shows that both passive attacks (eavesdropping of the wireless communication) and active attacks (impersonation and control of the medical devices to alter the intended therapy) can be successfully launched using public-domain information and widely available off-the-shelf hardware. The proposed attacks can compromise both the privacy and safety of patients. We propose two possible defenses against such attacks. One is based on rolling-code cryptographic protocols, and the other is based on body-coupled communication. Our security analysis shows that the proposed defenses have the potential to mitigate the security risks associated with personal healthcare systems. <s> BIB008 </s> Cyber-Physical Systems Security—A Survey <s> B. Cyber Controls 1) ICS Controls: a) Encryption and key management: <s> Supervisory Control and Data Acquisition (SCADA) systems are deployed worldwide in many critical infrastructures ranging from power generation, over public transport to industrial manufacturing systems. Whilst contemporary research has identified the need for protecting SCADA systems, these information are disparate and do not provide a coherent view of the threats and the risks resulting from the tendency to integrate these once isolated systems into corporate networks that are prone to cyber attacks. This paper surveys ongoing research and provides a coherent overview of the threats, risks and mitigation strategies in the area of SCADA security. <s> BIB009 </s> Cyber-Physical Systems Security—A Survey <s> B. Cyber Controls 1) ICS Controls: a) Encryption and key management: <s> The development of a trustworthy smart grid requires a deeper understanding of potential impacts resulting from successful cyber attacks. Estimating feasible attack impact requires an evaluation of the grid's dependency on its cyber infrastructure and its ability to tolerate potential failures. A further exploration of the cyber-physical relationships within the smart grid and a specific review of possible attack vectors is necessary to determine the adequacy of cybersecurity efforts. This paper highlights the significance of cyber infrastructure security in conjunction with power application security to prevent, mitigate, and tolerate cyber attacks. A layered approach is introduced to evaluating risk based on the security of both the physical power applications and the supporting cyber infrastructure. A classification is presented to highlight dependencies between the cyber-physical controls required to support the smart grid and the communication and computations that must be protected from cyber attack. The paper then presents current research efforts aimed at enhancing the smart grid's application and infrastructure security. Finally, current challenges are identified to facilitate future research efforts. <s> BIB010 </s> Cyber-Physical Systems Security—A Survey <s> B. Cyber Controls 1) ICS Controls: a) Encryption and key management: <s> The Smart Grid, regarded as the next generation power grid, uses two-way flows of electricity and information to create a widely distributed automated energy delivery network. In this article, we survey the literature till 2011 on the enabling technologies for the Smart Grid. We explore three major systems, namely the smart infrastructure system, the smart management system, and the smart protection system. We also propose possible future directions in each system. colorred{Specifically, for the smart infrastructure system, we explore the smart energy subsystem, the smart information subsystem, and the smart communication subsystem.} For the smart management system, we explore various management objectives, such as improving energy efficiency, profiling demand, maximizing utility, reducing cost, and controlling emission. We also explore various management methods to achieve these objectives. For the smart protection system, we explore various failure protection mechanisms which improve the reliability of the Smart Grid, and explore the security and privacy issues in the Smart Grid. <s> BIB011 </s> Cyber-Physical Systems Security—A Survey <s> B. Cyber Controls 1) ICS Controls: a) Encryption and key management: <s> Networked critical infrastructures improve our lives, but they are attractive targets for adversaries. In such infrastructures, to secure sensitive data is vital, as the information system is a foundation of today?s critical infrastructures, and data security is a main concern in such systems. Cryptography is an approach for data security, but this method should be altered according to various features of infrastructure networks. Since complex and distributed critical infrastructures usually spread over large geographic areas, different parts of those infrastructures have different levels of perimeter defense. Devices in weakly protected zones are more likely to be captured than those in well protected zones. If an adversary captures devices, s/he can bypass cyber security measures and obtain secret information directly. Such a threat requires a layered security mechanism that can prevent adversaries from invading the whole infrastructure network from these weak zones. In this article, we propose a layered encryption mechanism based on hash chain technology for protecting sensitive data. Besides showing the layered defense, the mechanism is also lightweight and has convenient key management. It can be used independently or as a supplement to existing security measures. We evaluate performance of the proposed mechanism over different kinds of devices. <s> BIB012 </s> Cyber-Physical Systems Security—A Survey <s> B. Cyber Controls 1) ICS Controls: a) Encryption and key management: <s> The Smart Grid, generally referred to as the next-generation power system, is considered as a revolutionary and evolutionary regime of existing power grids. More importantly, with the integration of advanced computing and communication technologies, the Smart Grid is expected to greatly enhance efficiency and reliability of future power systems with renewable energy resources, as well as distributed intelligence and demand response. Along with the silent features of the Smart Grid, cyber security emerges to be a critical issue because millions of electronic devices are inter-connected via communication networks throughout critical power facilities, which has an immediate impact on reliability of such a widespread infrastructure. In this paper, we present a comprehensive survey of cyber security issues for the Smart Grid. Specifically, we focus on reviewing and discussing security requirements, network vulnerabilities, attack countermeasures, secure communication protocols and architectures in the Smart Grid. We aim to provide a deep understanding of security vulnerabilities and solutions in the Smart Grid and shed light on future research directions for Smart Grid security. <s> BIB013 </s> Cyber-Physical Systems Security—A Survey <s> B. Cyber Controls 1) ICS Controls: a) Encryption and key management: <s> Utilities are rapidly deploying smart meters that measure electricity usage in real-time. Unfortunately, smart meters indirectly leak sensitive information about a home’s occupancy, which is easy to detect because it highly correlates with simple statistical metrics, such as power’s mean, variance, and range. To prevent occupancy detection, we propose using the thermal energy storage of electric water heaters already present in many homes. In essence, our approach, which we call combined heat and privacy (CHPr), modulates a water heater’s power usage to make it look like someone is always home. We design a CHPr-enabled water heater that regulates its energy usage to thwart a variety of occupancy detection attacks without violating its objective—to provide hot water on demand—and evaluate it in simulation using real data. Our results show that a standard 50-gal CHPr-enabled water heater prevents a wide range of state-of-the-art occupancy detection attacks. <s> BIB014 </s> Cyber-Physical Systems Security—A Survey <s> B. Cyber Controls 1) ICS Controls: a) Encryption and key management: <s> In Cyber-Physical Networked Systems (CPNS), attackers could inject false measurements to the controller through compromised sensor nodes, which not only threaten the security of the system, but also consumes network resources. To deal with this issue, a number of en-route filtering schemes have been designed for wireless sensor networks. However, these schemes either lack resilience to the number of compromised nodes or depend on the statically configured routes and node localization, which are not suitable for CPNS. In this paper, we propose a Polynomial-based Compromised-Resilient En-route Filtering scheme (PCREF), which can filter false injected data effectively and achieve a high resilience to the number of compromised nodes without relying on static routes and node localization. Particularly, PCREF adopts polynomials instead of MACs (message authentication codes) for endorsing measurement reports to achieve the resilience to attacks. Each node stores two types of polynomials: authentication polynomial and check polynomial derived from the primitive polynomial, and used for endorsing and verifying the measurement reports. Via extensive theoretical analysis and simulation experiments, our data show that PCREF achieves better filtering capacity and resilience to the large number of compromised nodes in comparison to the existing schemes. <s> BIB015
There is undoubtedly a need for encryption in ICS networks. One of the associated problems with encryption is the delay, which is not desirable in time-sensitive environments. Choi et al. BIB001 proposed an ICS-specific key management solution that does not cause delay. In addition, Cao et al. BIB012 proposed a layered approach aiming to protect sensitive data in the widespread ICS environments. Their technique relies on hash chains to provide: 1) layered protection such that ICS is split into two zones: a) high and b) low security levels and 2) a lightweight key management mechanism. Thanks to the layered approach, an attacker with full control of a device in the low security level cannot intercept data from higher security level zones. b) Software controls: Regular patching of security vulnerabilities in operating systems and their applications is a vital security practice. Windows released Stuxnet-related security patches, without which, Stuxnet would have still been present  . However, vendors of ICS applications must also keep up with the patching and release compatible versions of their applications. This ensures that ICS operators do not resort to older versions of vulnerable OS to be able to use the compatible ICS application BIB003 . c) Standardization: The National Institute of Standards and Technology (NIST) is one of the leading bodies in the standardization realm. Following ICS security standards like theirs, among others, should significantly contribute to securing ICS. For example, Stouffer et al. BIB005 provided a comprehensive guideline for ICS security. They provided guidelines for technical controls such as firewalls, IDS, and access control, and operational controls such as personnel security, awareness, and training. In fact, technical and operational controls must always go hand in hand, and the negligence of one leads to serious attacks. For example, lack of awareness could make employees vulnerable to social engineering attacks such as phishing. ICS-CERT reported that most of the attacks on ICS originated from phishing emails with malware-infected attachments  . In addition, security experts evaluated the security of an ICS corporation, and were able, through social engineering and phishing, to gain employees' credentials BIB009 . Sommestad et al. BIB004 conducted a comparison, based on keywords mining, and concluded that the standards focus either on technical controls, or operational controls, but not both. In addition, some standards somewhat neglect ICS-specific properties and focus on IT security countermeasures alone. 2) Smart Grids Controls: a) DoS controls: Attacks on communication components should be prevented or, at least, detected. On the one hand, at the network layer, prevention of attacks like DoS is usually achieved by rate-limiting, filtering malicious packets, and reconfiguration of network architecture. The first two are possible in smart grids, while the last might be difficult due to its relatively static nature. Furthermore, techniques at the physical layer aim at preventing attacks of the nature of wireless jamming. On the other hand, DoS detection techniques are categorized into four types: 1) signal-based; 2) packet-based; 3) proactive; and 4) hybrid detection BIB013 . b) Privacy-preserving controls: Lack of confidentiality in data aggregation protocols (DAPs) might result in privacy invasion of consumers' private information such as billing information and usage patterns BIB002 , while the lack of integrity could result in disruption in state estimation and consumption reports BIB010 . Therefore, a number of privacypreserving techniques have emerged to provide aggregated data with confidentiality and integrity when in transit between smart meters and control centers BIB011 , BIB013 . Another privacy concern that might affect safety or finance is the ability to detect the (in)occupancy of a house to break in. Chen et al. BIB014 proposed combined heat and privacy mechanism such that it makes the poser usage data always looks like the house is occupied and, therefore, tricks occupancy detection techniques. c) False data injection controls: Yang et al. BIB015 proposed a polynomial-based compromise-resilient en-route filtering scheme. They aimed to filter prevent FDI attacks by filtering the false data effectively and achieving a high resilience to the number of compromised nodes without relying on static routes and node localization. d) Standardization: A number of bodies, such as the IEC and NIST, have developed a set of standards for securing smart grids' communications. For example, IEC's have developed standards TC57 and 6235  , while NIST has developed guidelines for smart grids in report 7628  . 3) Medical Devices Controls: a) Shifting security to wearable devices: Incorporating security into the current IMDs and wearable devices has its own risks and challenges. One of which is the health risk associated with IMDs' surgical extraction from a patient in order to update or replace an IMD with more secure one. In fact, even if we assume that there are no health risks for extracting IMDs, the cryptographic operations required for any secure system are still expensive in terms of computational, memory, and battery resources. Therefore, the intuitive solution is to add another device built specifically to add security. Several proposals that deploy some cryptographic and antijamming-attack mechanisms utilize external wearable devices to realize such mechanisms. For example, Xu et al. BIB006 proposed IMDGuard to defend against jamming and spoofing attacks. In addition, Gollakota et al. BIB007 proposed an external wearable device, the shield, to detect and prevent any unauthorized commands sent to an IMD. They evaluated the shield on two modern IMDs, i.e., ICD and cardiac resynchronization therapy device. This device jams any signals initiated by unauthorized party. b) Cross-domain solutions: Li et al. BIB008 proposed the adoption of the rolling code encryption mechanism used in RKE in cars. Smart cars and medical devices both share similar features in terms of computation limitations, power, and data bandwidth constraints. Therefore, using rolling code encryption should be an effective solution to prevent eavesdropping and replay attacks. c) Standardization and recommendations: The Food and Drug Administration (FDA) is the leading body in medical devices' standardization. It has issued a number of standards and guidelines for the manufacturers of medical devices. For example, in 2005, the FDA highlighted that potential vulnerabilities might result from using COTS software equipped with remote access capabilities  . Another recommendation was published in 2014 about cybersecurity in medical devices  . However, the recommendations are not detailed enough nor mandatory, rather "nonbinding recommendations." Therefore, manufacturers have the liberty to choose not to follow them, which certainly would contribute to the production of less secure medical devices. In addition, IEEE 802.15.6 is the latest BAN standard that provides security services such as authentication and encryption  .