Cyber-Physical Systems Security—A Survey <s> 4) Explicit Trust: <s> A power grid is a complex system connecting electric power generators to consumers through power transmission and distribution networks across a large geographical area. System monitoring is necessary to ensure the reliable operation of power grids, and state estimation is used in system monitoring to best estimate the power grid state through analysis of meter measurements and power system models. Various techniques have been developed to detect and identify bad measurements, including interacting bad measurements introduced by arbitrary, nonrandom causes. At first glance, it seems that these techniques can also defeat malicious measurements injected by attackers. In this article, we expose an unknown vulnerability of existing bad measurement detection algorithms by presenting and analyzing a new class of attacks, called false data injection attacks, against state estimation in electric power grids. Under the assumption that the attacker can access the current power system configuration information and manipulate the measurements of meters at physically protected locations such as substations, such attacks can introduce arbitrary errors into certain state variables without being detected by existing algorithms. Moreover, we look at two scenarios, where the attacker is either constrained to specific meters or limited in the resources required to compromise meters. We show that the attacker can systematically and efficiently construct attack vectors in both scenarios to change the results of state estimation in arbitrary ways. We also extend these attacks to generalized false data injection attacks, which can further increase the impact by exploiting measurement errors typically tolerated in state estimation. We demonstrate the success of these attacks through simulation using IEEE test systems, and also discuss the practicality of these attacks and the real-world constraints that limit their effectiveness. <s> BIB001 </s> Cyber-Physical Systems Security—A Survey <s> 4) Explicit Trust: <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> BIB002 </s> Cyber-Physical Systems Security—A Survey <s> 4) Explicit Trust: <s> Many people think of the Smart Grid as a power distribution group built on advanced smart metering-but that's just one aspect of a much larger and more complex system. The "Smart Grid" requires new technologies throughout energy generation, transmission and distribution, and even the homes and businesses being served by the grid. This also represents new information paths between these new systems and services, all of which represents risk, requiring a more thorough approach to where and how cyber security controls are implemented. ::: ::: This insight provides a detailed architecture of the entire Smart Grid, with recommended cyber security measures for everything from the supply chain to the consumer. ::: ::: ::: ::: Discover the potential of the Smart Grid ::: Learn in depth about its systems ::: See its vulnerabilities and how best to protect it ::: ::: Table of Contents ::: ::: ::: Introduction ::: ::: Chapter 1: What is the Smart Grid? ::: ::: Chapter 2:?Smart Grid Network Architecture ::: ::: Chapter 3: Hacking the Smart Grid ::: ::: Chapter 4: Privacy Concerns with the Smart Grid ::: ::: Chapter 5: Security Models for SCADA, ICS and Smart Grid ::: ::: Chapter 6: Securing the Smart Grid ::: ::: Chapter 7: Securing the Supply Chain ::: ::: Chapter 8: The Future of the Grid ::: ::: Appendix A: Reference Models and Architectures ::: ::: Appendix B: Continued Reading ::: ::: Glossary <s> BIB003
Sensed data and sent commands should not be explicitly trusted. Instead, new mechanisms are needed to detect false data and unauthorized commands  . With the large size of smart grids, it becomes difficult to detect FDI attacks by relying on algorithms that have been designed to only detect faults BIB001 . 5) Comprehensive Security: Security measures and tools mainly exist at higher levels in smart grids and their effectiveness decreases toward lower levels. In other words, the sophistication of security measures decreases in lower levels due to the limited capabilities in low-level devices. Hence, security needs to be involved in every part of smart grids, starting from the lowest levels, i.e., field devices and their protocols, to high levels, e.g., control centers. Implementing security at lower levels might have some performance costs. Therefore, lightweight solutions are desired BIB003 . The use of encryption is necessary to provide confidentiality and integrity at all levels of smart grids. However, the challenge is not in deploying it, rather, it is in doing it cost-effectively in low level components. 6) Change Management: Managing changes in smart grids is no less challenging than it is in ICS. Smart grids are certainly more diverse and have more stakeholders than ICS applications, and yet its change management capabilities are limited BIB002 . This makes change management an immensely desired requirement for more secure smart grids.