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Salmani, Hassan, Hoque, Tamzidul, Bhunia, Swarup, Yasin, Muhammad, Rajendran, Jeyavijayan JV, Karimi, Naghmeh.  2019.  Special Session: Countering IP Security Threats in Supply Chain. 2019 IEEE 37th VLSI Test Symposium (VTS). :1–9.

The continuing decrease in feature size of integrated circuits, and the increase of the complexity and cost of design and fabrication has led to outsourcing the design and fabrication of integrated circuits to third parties across the globe, and in turn has introduced several security vulnerabilities. The adversaries in the supply chain can pirate integrated circuits, overproduce these circuits, perform reverse engineering, and/or insert hardware Trojans in these circuits. Developing countermeasures against such security threats is highly crucial. Accordingly, this paper first develops a learning-based trust verification framework to detect hardware Trojans. To tackle Trojan insertion, IP piracy and overproduction, logic locking schemes and in particular stripped functionality logic locking is discussed and its resiliency against the state-of-the-art attacks is investigated.

Samaila, Musa G., Sequeiros, João B. F., Freire, Mário M., Inácio, Pedro R. M..  2018.  Security Threats and Possible Countermeasures in IoT Applications Covering Different Industry Domains. Proceedings of the 13th International Conference on Availability, Reliability and Security. :16:1-16:9.

The world is witnessing the emerging role of Internet of Things (IoT) as a technology that is transforming different industries, global community and its economy. Currently a plethora of interconnected smart devices have been deployed for diverse pervasive applications and services, and billions more are expected to be connected to the Internet in the near future. The potential benefits of IoT include improved quality of life, convenience, enhanced energy efficiency, and more productivity. Alongside these potential benefits, however, come increased security risks and potential for abuse. Arguably, this is partly because many IoT start-ups and electronics hobbyists lack security expertise, and some established companies do not make security a priority in their designs, and hence they produce IoT devices that are often ill-equipped in terms of security. In this paper, we discuss different IoT application areas, and identify security threats in IoT architecture. We consider security requirements and present typical security threats for each of the application domains. Finally, we present several possible security countermeasures, and introduce the IoT Hardware Platform Security Advisor (IoT-HarPSecA) framework, which is still under development. IoT-HarPSecA is aimed at facilitating the design and prototyping of secure IoT devices.

Samaniego, M., Deters, R..  2018.  Zero-Trust Hierarchical Management in IoT. 2018 IEEE International Congress on Internet of Things (ICIOT). :88-95.

Internet of Things (IoT) is experiencing exponential scalability. This scalability introduces new challenges regarding management of IoT networks. The question that emerges is how we can trust the constrained infrastructure that shortly is expected to be formed by millions of 'things.' The answer is not to trust. This research introduces Amatista, a blockchain-based middleware for management in IoT. Amatista presents a novel zero-trust hierarchical mining process that allows validating the infrastructure and transactions at different levels of trust. This research evaluates Amatista on Edison Arduino Boards.

Sámano-Robles, Ramiro.  2019.  MAC-PRY Cross-Layer Design for Secure Wireless Avionics Intra-Communications. 2019 Eighth International Conference on Emerging Security Technologies (EST). :1–7.
This paper presents a framework for medium access control (MAC) and physical (PRY) cross-layer security design of wireless avionics intra-communications (WAICs). The paper explores the different options based on the latest results of MAC-PRY cross-layer design and the available standard technologies for WAICs. Particular emphasis is given to solutions based on multiple-input multiple-output (MIMO) systems and recent developments towards a wireless technology with ultra-low latency and high reliability in the context of 5G and machine-type traffic support. One major objective is to improve WAICs technology and thus match the real-time, reliability and safety critical performance of the internal aeronautics bus technologies (e.g., ARINC 664). The main identified vulnerabilities and potential solutions are explored, as well as their impact on system design complexity and feasibility for wireless networks on-board aircraft. The solutions are presented in the context of the European project SCOTT (secure connected trustable things) using the recently released reference architecture for trusted IoT systems. Other aspects of SCOTT such as trust, privacy, security classes, and safety are also discussed here for the aeronautics domain.
Samanta, P., Kelly, E., Bashir, A., Debroy, S..  2018.  Collaborative Adversarial Modeling for Spectrum Aware IoT Communications. 2018 International Conference on Computing, Networking and Communications (ICNC). :447–451.
In order to cater the growing spectrum demands of large scale future 5G Internet of Things (IoT) applications, Dynamic Spectrum Access (DSA) based networks are being proposed as a high-throughput and cost-effective solution. However the lack of understanding of DSA paradigm's inherent security vulnerabilities on IoT networks might become a roadblock towards realizing such spectrum aware 5G vision. In this paper, we make an attempt to understand how such inherent DSA vulnerabilities in particular Spectrum Sensing Data Falsification (SSDF) attacks can be exploited by collaborative group of selfish adversaries and how that can impact the performance of spectrum aware IoT applications. We design a utility based selfish adversarial model mimicking collaborative SSDF attack in a cooperative spectrum sensing scenario where IoT networks use dedicated environmental sensing capability (ESC) for spectrum availability estimation. We model the interactions between the IoT system and collaborative selfish adversaries using a leader-follower game and investigate the existence of equilibrium. Using simulation results, we show the nature of adversarial and system utility components against system variables. We also explore Pareto-optimal adversarial strategy design that maximizes the attacker utility for varied system strategy spaces.
Samantray, Om Prakash, Tripathy, Satya Narayan, Das, Susanta Kumar.  2019.  A study to Understand Malware Behavior through Malware Analysis. 2019 IEEE International Conference on System, Computation, Automation and Networking (ICSCAN). :1–5.
Most of the malware detection techniques use malware signatures for detection. It is easy to detect known malicious program in a system but the problem arises when the malware is unknown. Because, unknown malware cannot be detected by using available known malware signatures. Signature based detection techniques fails to detect unknown and zero-day attacks. A novel approach is required to represent malware features effectively to detect obfuscated, unknown, and mutated malware. This paper emphasizes malware behavior, characteristics and properties extracted by different analytic techniques and to decide whether to include them to create behavioral based malware signature. We have made an attempt to understand the malware behavior using a few openly available tools for malware analysis.
Sambasivan, Raja R., Shafer, Ilari, Mace, Jonathan, Sigelman, Benjamin H., Fonseca, Rodrigo, Ganger, Gregory R..  2016.  Principled Workflow-centric Tracing of Distributed Systems. Proceedings of the Seventh ACM Symposium on Cloud Computing. :401–414.

Workflow-centric tracing captures the workflow of causally-related events (e.g., work done to process a request) within and among the components of a distributed system. As distributed systems grow in scale and complexity, such tracing is becoming a critical tool for understanding distributed system behavior. Yet, there is a fundamental lack of clarity about how such infrastructures should be designed to provide maximum benefit for important management tasks, such as resource accounting and diagnosis. Without research into this important issue, there is a danger that workflow-centric tracing will not reach its full potential. To help, this paper distills the design space of workflow-centric tracing and describes key design choices that can help or hinder a tracing infrastructures utility for important tasks. Our design space and the design choices we suggest are based on our experiences developing several previous workflow-centric tracing infrastructures.

Samet, Saeed, Ishraque, Mohd Tazim, Sharma, Anupam.  2018.  Privacy-Preserving Personal Health Record (P3HR): A Secure Android Application. Proceedings of the 7th International Conference on Software and Information Engineering. :22–26.

In contrast to the Electronic Medical Record (EMR) and Electronic Health Record (EHR) systems that are created to maintain and manage patient data by health professionals and organizations, Personal Health Record (PHR) systems are operated and managed by patients. Therefore, it necessitates increased attention to the importance of security and privacy challenges, as patients are most often unfamiliar with the potential security threats that can result from release of their health data. On the other hand, the use of PHR systems is increasingly becoming an important part of the healthcare system by sharing patient information among their circle of care. To have a system with a more favorable interface and a high level of security, it is crucial to provide a mobile application for PHR that fulfills six important features: (1) ease the usage for various patient demographics and their delegates, (2) security, (3) quickly transfer patient data to their health professionals, (4) give the ability of access revocation to the patient, (5) provide ease of interaction between patients and their circle of care, and (6) inform patients about any instances of access to their data by their circle of care. In this work, we propose an implementation of a Privacy-Preserving PHR system (P3HR) for Android devices to fulfill the above six characteristics, using a Ciphertext Policy Attribute Based Encryption to enhance security and privacy of the system, as well as providing access revocation in a hierarchical scheme of the health professionals and organizations involved. Using this application, patients can securely store their health data, share the records, and receive feedback and recommendations from their circle of care.

Samir, Nagham, Gamal, Yousef, El-Zeiny, Ahmed N., Mahmoud, Omar, Shawky, Ahmed, Saeed, AbdelRahman, Mostafa, Hassan.  2019.  Energy-Adaptive Lightweight Hardware Security Module using Partial Dynamic Reconfiguration for Energy Limited Internet of Things Applications. 2019 IEEE International Symposium on Circuits and Systems (ISCAS). :1—4.
Data security is the main challenge in Internet of Things (IoT) applications. Security strength and the immunity to security attacks depend mainly on the available power budget. The power-security level trade-off is the main challenge for low power IoT applications, especially, energy limited IoT applications. In this paper, multiple encryption modes that provide different power consumption and security level values are hardware implemented. In other words, some modes provide high security levels at the expense of high power consumption and other modes provide low power consumption with low security level. Dynamic Partial Reconfiguration (DPR) is utilized to adaptively configure the hardware security module based on the available power budget. For example, for a given power constraint, the DPR controller configures the security module with the security mode that meets the available power constraint. ZC702 evaluation board is utilized to implement the proposed encryption modes using DPR. A Lightweight Authenticated Cipher (ACORN) is the most suitable encryption mode for low power IoT applications as it consumes the minimum power and area among the selected candidates at the expense of low throughput. The whole DPR system is tested with a maximum dynamic power dissipation of 10.08 mW. The suggested DPR system saves about 59.9% of the utilized LUTs compared to the individual implementation of the selected encryption modes.
Samira Tasharofi, University of Illinois at Urbana-Champaign, Peter Dinges, University of Illinois at Urbana-Champaign, Ralph E. Johnson, University of Illinois at Urbana-Champaign.  2013.  Why Do Scala Developers Mix the Actor Model with other Concurrency Models?

Mixing the actor model with other concurrency models in a single program can break the actor abstraction. This increases the chance of creating deadlocks and data races—two mistakes that are hard to make with actors. Furthermore, it prevents the use of many advanced testing, modeling, and verification tools for actors, as these require pure actor programs. This study is the first to point out the phenomenon of mixing concurrency models by Scala developers and to systematically identify the factors leading to it. We studied 15 large, mature, and actively maintained actor programs written in Scala and found that 80% of them mix the actor model with another concurrency model. Consequently, a large part of real-world actor programs does not use actors to their fullest advantage. Inspection of the programs and discussion with the developers reveal two reasons for mixing that can be influenced by researchers and library-builders: weaknesses in the actor library implementations, and shortcomings of the actor model itself.

Sammoud, A., Chalouf, M. A., Hamdi, O., Montavont, N., Bouallegue, A..  2020.  A secure three-factor authentication and biometrics-based key agreement scheme for TMIS with user anonymity. 2020 International Wireless Communications and Mobile Computing (IWCMC). :1916—1921.

E- Health systems, specifically, Telecare Medical Information Systems (TMIS), are deployed in order to provide patients with specific diseases with healthcare services that are usually based on remote monitoring. Therefore, making an efficient, convenient and secure connection between users and medical servers over insecure channels within medical services is a rather major issue. In this context, because of the biometrics' characteristics, many biometrics-based three factor user authentication schemes have been proposed in the literature to secure user/server communication within medical services. In this paper, we make a brief study of the most interesting proposals. Then, we propose a new three-factor authentication and key agreement scheme for TMIS. Our scheme tends not only to fix the security drawbacks of some studied related work, but also, offers additional significant features while minimizing resource consumption. In addition, we perform a formal verification using the widely accepted formal security verification tool AVISPA to demonstrate that our proposed scheme is secure. Also, our comparative performance analysis reveals that our proposed scheme provides a lower resource consumption compared to other related work's proposals.

Samotyja, Jacek, Lemke-Rust, Kerstin.  2016.  Practical Results of ECC Side Channel Countermeasures on an ARM Cortex M3 Processor.

This paper presents implementation results of several side channel countermeasures for protecting the scalar multiplication of ECC (Elliptic Curve Cryptography) implemented on an ARM Cortex M3 processor that is used in security sensitive wireless sensor nodes. Our implementation was done for the ECC curves P-256, brainpool256r1, and Ed25519. Investigated countermeasures include Double-And-Add Always, Montgomery Ladder, Scalar Randomization, Randomized Scalar Splitting, Coordinate Randomization, and Randomized Sliding Window. Practical side channel tests for SEMA (Simple Electromagnetic Analysis) and MESD (Multiple Exponent, Single Data) are included. Though more advanced side channel attacks are not evaluated, yet, our results show that an appropriate level of resistance against the most relevant attacks can be reached.

Sampigethaya, K., Kopardekar, P., Davis, J..  2018.  Cyber Security of Unmanned Aircraft System Traffic Management (UTM). 2018 Integrated Communications, Navigation, Surveillance Conference (ICNS). :1C1–1–1C1–15.

Millions of small Unmanned Aircraft System (sUAS) aircraft of various shapes and capabilities will soon fly at low altitudes in urban environments for ambitious applications. It is critical to ensure these remotely piloted aircraft fly safely, predictably, and efficiently in this challenging airspace, without endangering themselves and other occupants sharing that airspace or in proximity. Concepts, technologies, processes, and policies to solve this hard problem of UAS Traffic Management (UTM) are being explored. But, cyber security considerations are largely missing. This paper bridges this gap and addresses UTM cyber security needs and issues. It contributes a comprehensive framework to understand, identify, classify, and assess security threats to UTM, including those resulting from sUAS vulnerabilities. Promising threat mitigations, major challenges, and research directions are discussed to secure UTM.

Samriya, Jitendra Kumar, Kumar, Narander.  2020.  Fuzzy Ant Bee Colony For Security And Resource Optimization In Cloud Computing. 2020 5th International Conference on Computing, Communication and Security (ICCCS). :1—5.

Cloud computing (CC) systems prevail to be the widespread computational paradigms for offering immense scalable and elastic services. Computing resources in cloud environment should be scheduled to facilitate the providers to utilize the resources moreover the users could get low cost applications. The most prominent need in job scheduling is to ensure Quality of service (QoS) to the user. In the boundary of the third party the scheduling takes place hence it is a significant condition for assuring its security. The main objective of our work is to offer QoS i.e. cost, makespan, minimized migration of task with security enforcement moreover the proposed algorithm guarantees that the admitted requests are executed without violating service level agreement (SLA). These objectives are attained by the proposed Fuzzy Ant Bee Colony algorithm. The experimental outcome confirms that secured job scheduling objective with assured QoS is attained by the proposed algorithm.

Samson, A., Gopalan, N. P..  2016.  Software Defined Networking: Identification of Pathways for Security Threats. Proceedings of the International Conference on Informatics and Analytics. :16:1–16:6.
As Industries and Data Center plan to implement Software Defined Networking (SDN), the main concern is the anxiety about security. The Industries and Data Centers are curious to know how a SDN product will support them that their data, supporting applications and built in infrastructure are not vulnerable to threats. The initiation of SDN, will demand new pathways for securing control plane traffic. The traditional networks usually trust switching intelligence to implement various defense mechanisms besides known attacks. Many attacks which distress traditional networks also affect SDNs, partially due to SDN architecture complexities and most prominent among them is DoS. This paper identifies the pathways of threats to SDN systems and discuss methods to ways to mitigate them.
Samudrala, A. N., Blum, R. S..  2017.  Asymptotic Analysis of a New Low Complexity Encryption Approach for the Internet of Things, Smart Cities and Smart Grid. 2017 IEEE International Conference on Smart Grid and Smart Cities (ICSGSC). :200–204.

Parameter estimation in wireless sensor networks (WSN) using encrypted non-binary quantized data is studied. In a WSN, sensors transmit their observations to a fusion center through a wireless medium where the observations are susceptible to unauthorized eavesdropping. Encryption approaches for WSNs with fixed threshold binary quantization were previously explored. However, fixed threshold binary quantization limits parameter estimation to scalar parameters. In this paper, we propose a stochastic encryption approach for WSNs that can operate on non-binary quantized observations and has the capability for vector parameter estimation. We extend a binary stochastic encryption approach proposed previously, to a non-binary generalized case. Sensor outputs are quantized using a quantizer with R + 1 levels, where R $ε$ 1, 2, 3,..., encrypted by flipping them with certain flipping probabilities, and then transmitted. Optimal estimators using maximum-likelihood estimation are derived for both a legitimate fusion center (LFC) and a third party fusion center (TPFC) perspectives. We assume the TPFC is unaware of the encryption. Asymptotic analysis of the estimators is performed by deriving the Cramer-Rao lower bound for LFC estimation, and the asymptotic bias and variance for TPFC estimation. Numerical results validating the asymptotic analysis are presented.

Samuel, C., Alvarez, B. M., Ribera, E. Garcia, Ioulianou, P. P., Vassilakis, V. G..  2020.  Performance Evaluation of a Wormhole Detection Method using Round-Trip Times and Hop Counts in RPL-Based 6LoWPAN Networks. 2020 12th International Symposium on Communication Systems, Networks and Digital Signal Processing (CSNDSP). :1–6.
The IPv6 over Low-power Wireless Personal Area Network (6LoWPAN) has been standardized to support IP over lossy networks. RPL (Routing Protocol for Low-Power and Lossy Networks) is the common routing protocol for 6LoWPAN. Among various attacks on RPL-based networks, the wormhole attack may cause severe network disruption and is one of the hardest to detect. We have designed and implemented in ContikiOS a wormhole detection technique for 6LoWPAN, that uses round-trip times and hop counts. In addition, the performance of this technique has been evaluated in terms of power, CPU, memory, and communication overhead.
Samuel, J., Aalab, K., Jaskolka, J..  2020.  Evaluating the Soundness of Security Metrics from Vulnerability Scoring Frameworks. 2020 IEEE 19th International Conference on Trust, Security and Privacy in Computing and Communications (TrustCom). :442—449.

Over the years, a number of vulnerability scoring frameworks have been proposed to characterize the severity of known vulnerabilities in software-dependent systems. These frameworks provide security metrics to support decision-making in system development and security evaluation and assurance activities. When used in this context, it is imperative that these security metrics be sound, meaning that they can be consistently measured in a reproducible, objective, and unbiased fashion while providing contextually relevant, actionable information for decision makers. In this paper, we evaluate the soundness of the security metrics obtained via several vulnerability scoring frameworks. The evaluation is based on the Method for DesigningSound Security Metrics (MDSSM). We also present several recommendations to improve vulnerability scoring frameworks to yield more sound security metrics to support the development of secure software-dependent systems.

Samwel, Niels, Daemen, Joan.  2017.  DPA on Hardware Implementations of Ascon and Keyak. Proceedings of the Computing Frontiers Conference. :415–424.

This work applies side channel analysis on hardware implementations of two CAESAR candidates, Keyak and Ascon. Both algorithms are cryptographic sponges with an iterated permutation. The algorithms share an s-box so attacks on the non-linear step of the permutation are similar. This work presents the first results of a DPA attack on Keyak using traces generated by an FPGA. A new attack is crafted for a larger sensitive variable to reduce the number of traces. It also presents and applies the first CPA attack on Ascon. Using a toy-sized threshold implementation of Ascon we try to give insight in the order of the steps of a permutation.

Sanandaji, B.M., Bitar, E., Poolla, K., Vincent, T.L..  2014.  An abrupt change detection heuristic with applications to cyber data attacks on power systems. American Control Conference (ACC), 2014. :5056-5061.

We present an analysis of a heuristic for abrupt change detection of systems with bounded state variations. The proposed analysis is based on the Singular Value Decomposition (SVD) of a history matrix built from system observations. We show that monitoring the largest singular value of the history matrix can be used as a heuristic for detecting abrupt changes in the system outputs. We provide sufficient detectability conditions for the proposed heuristic. As an application, we consider detecting malicious cyber data attacks on power systems and test our proposed heuristic on the IEEE 39-bus testbed.
 

Sanchez-Rola, Iskander, Balzarotti, Davide, Santos, Igor.  2017.  The Onions Have Eyes: A Comprehensive Structure and Privacy Analysis of Tor Hidden Services. Proceedings of the 26th International Conference on World Wide Web. :1251–1260.

Tor is a well known and widely used darknet, known for its anonymity. However, while its protocol and relay security have already been extensively studied, to date there is no comprehensive analysis of the structure and privacy of its Web Hidden Service. To fill this gap, we developed a dedicated analysis platform and used it to crawl and analyze over 1.5M URLs hosted in 7257 onion domains. For each page we analyzed its links, resources, and redirections graphs, as well as the language and category distribution. According to our experiments, Tor hidden services are organized in a sparse but highly connected graph, in which around 10% of the onions sites are completely isolated. Our study also measures for the first time the tight connection that exists between Tor hidden services and the Surface Web. In fact, more than 20% of the onion domains we visited imported resources from the Surface Web, and links to the Surface Web are even more prevalent than to other onion domains. Finally, we measured for the first time the prevalence and the nature of web tracking in Tor hidden services, showing that, albeit not as widespread as in the Surface Web, tracking is notably present also in the Dark Web: more than 40% of the scripts are used for this purpose, with the 70% of them being completely new tracking scripts unknown by existing anti-tracking solutions.

Sanchez, Cristian, Martinez-Mosquera, Diana, Navarrete, Rosa.  2019.  Matlab Simulation of Algorithms for Face Detection in Video Surveillance. 2019 International Conference on Information Systems and Software Technologies (ICI2ST). :40–47.
Face detection is an application widely used in video surveillance systems and it is the first step for subsequent applications such as monitoring and recognition. For facial detection, there are a series of algorithms that allow the face to be extracted in a video image, among which are the Viola & Jones waterfall method and the method by geometric models using the Hausdorff distance. In this article, both algorithms are theoretically analyzed and the best one is determined by efficiency and resource optimization. Considering the most common problems in the detection of faces in a video surveillance system, such as the conditions of brightness and the angle of rotation of the face, tests have been carried out in 13 different scenarios with the best theoretically analyzed algorithm and its combination with another algorithm The images obtained, using a digital camera in the 13 scenarios, have been analyzed using Matlab code of the Viola & Jones and Viola & Jones algorithm combined with the Kanade-Lucas-Tomasi algorithm to add the feature of completing the tracking of a single object. This paper presents the detection percentages, false positives and false negatives for each image and for each simulation code, resulting in the scenarios with the most detection problems and the most accurate algorithm in face detection.
Sánchez, Marco, Torres, Jenny, Zambrano, Patricio, Flores, Pamela.  2018.  FraudFind: Financial fraud detection by analyzing human behavior. 2018 IEEE 8th Annual Computing and Communication Workshop and Conference (CCWC). :281–286.
Financial fraud is commonly represented by the use of illegal practices where they can intervene from senior managers until payroll employees, becoming a crime punishable by law. There are many techniques developed to analyze, detect and prevent this behavior, being the most important the fraud triangle theory associated with the classic financial audit model. In order to perform this research, a survey of the related works in the existing literature was carried out, with the purpose of establishing our own framework. In this context, this paper presents FraudFind, a conceptual framework that allows to identify and outline a group of people inside an banking organization who commit fraud, supported by the fraud triangle theory. FraudFind works in the approach of continuous audit that will be in charge of collecting information of agents installed in user's equipment. It is based on semantic techniques applied through the collection of phrases typed by the users under study for later being transferred to a repository for later analysis. This proposal encourages to contribute with the field of cybersecurity, in the reduction of cases of financial fraud.
Sandbank, Tommy, Shmueli-Scheuer, Michal, Herzig, Jonathan, Konopnicki, David, Shaul, Rottem.  2017.  EHCTool: Managing Emotional Hotspots for Conversational Agents. Proceedings of the 22Nd International Conference on Intelligent User Interfaces Companion. :125–128.

Building conversational agents is becoming easier thanks to the profusion of designated platforms. Integrating emotional intelligence in such agents contributes to positive user satisfaction. Currently, this integration is implemented using calls to an emotion analysis service. In this demonstration we present EHCTool that aims to detect and notify the conversation designer about problematic conversation states where emotions are likely to be expressed by the user. Using its exploration view, the tool assists the designer to manage and define appropriate responses in these cases.

Sandberg, H., Teixeira, A. M. H..  2016.  From control system security indices to attack identifiability. 2016 Science of Security for Cyber-Physical Systems Workshop (SOSCYPS). :1–6.

In this paper, we investigate detectability and identifiability of attacks on linear dynamical systems that are subjected to external disturbances. We generalize a concept for a security index, which was previously introduced for static systems. The index exactly quantifies the resources necessary for targeted attacks to be undetectable and unidentifiable in the presence of disturbances. This information is useful for both risk assessment and for the design of anomaly detectors. Finally, we show how techniques from the fault detection literature can be used to decouple disturbances and to identify attacks, under certain sparsity constraints.