Biblio

Found 328 results

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2022-06-06
Matsushita, Haruka, Sato, Kaito, Sakura, Mamoru, Sawada, Kenji, Shin, Seiichi, Inoue, Masaki.  2020.  Rear-wheel steering control reflecting driver personality via Human-In-The-Loop System. 2020 IEEE International Conference on Systems, Man, and Cybernetics (SMC). :356–362.
One of the typical autonomous driving systems is a human-machine cooperative system that intervenes in the driver operation. The autonomous driving needs to make consideration of the driver individuality in addition to safety. This paper considers a human-machine cooperative system balancing safety with the driver individuality using the Human-In-The-Loop System (HITLS) for rear-wheel steering control. This paper assumes that it is safe for HITLS to follow the target side-slip angle and target angular velocity without conflicts between the controller and driver operations. We propose HITLS using the primal-dual algorithm and the internal model control (IMC) type I-PD controller. In HITLS, the signal expander delimits the human-selectable operating range and the controller cooperates stably the human operation and automated control in that range. The primal-dual algorithm realizes the driver and the signal expander. Our outcomes are the making of the rear-wheel steering system which converges to the target value while reflecting the driver individuality.
2021-10-12
Remlein, Piotr, Rogacki, Mikołaj, Stachowiak, Urszula.  2020.  Tamarin software – the tool for protocols verification security. 2020 Baltic URSI Symposium (URSI). :118–123.
In order to develop safety-reliable standards for IoT (Internet of Things) networks, appropriate tools for their verification are needed. Among them there is a group of tools based on automated symbolic analysis. Such a tool is Tamarin software. Its usage for creating formal proofs of security protocols correctness has been presented in this paper using the simple example of an exchange of messages with asynchronous encryption between two agents. This model can be used in sensor networks or IoT e.g. in TLS protocol to provide a mechanism for secure cryptographic key exchange.
2021-04-27
Xie, J., She, H., Chen, X., Zhang, H., Niu, Y..  2020.  Test Method for Automatic Detection Capability of Civil Aviation Security Equipment Using Bayesian Estimation. 2020 IEEE 2nd International Conference on Civil Aviation Safety and Information Technology (ICCASIT. :831–835.
There are a lot of emerging security equipment required to be tested on detection rate (DR) and false alarm rate (FAR) for prohibited items. This article imports Bayesian approach to accept or reject DR and FAR. The detailed quantitative predictions can be made through the posterior distribution obtained by Markov chain Monte Carlo method. Based on this, HDI + ROPE decision rule is established. For the tests that need to make early decision, HDI + ROPE stopping rule is presented with biased estimate value, and criterial precision rule is presented with unbiased estimate value. Choosing the stopping rule according to the test purpose can achieve the balance of efficiency and accuracy.
2021-07-08
Su, Yishan, Zhang, Ting, Jin, Zhigang, Guo, Lei.  2020.  An Anti-Attack Trust Mechanism Based on Collaborative Spectrum Sensing for Underwater Acoustic Sensor Networks. Global Oceans 2020: Singapore – U.S. Gulf Coast. :1—5.
The main method for long-distance underwater communication is underwater acoustic communication(UAC). The bandwidth of UAC channel is narrow and the frequency band resources are scarce. Therefore, it is important to improve the frequency band utilization of UAC system. Cognitive underwater acoustic (CUA) technology is an important method. CUA network can share spectrum resources with the primary network. Spectrum sensing (SS) technology is the premise of realizing CUA. Therefore, improving the accuracy of spectral sensing is the main purpose of this paper. However, the realization of underwater SS technology still faces many difficulties. First, underwater energy supplies are scarce, making it difficult to apply complex algorithms. Second, and more seriously, CUA network can sometimes be attacked and exploited by hostile forces, which will not only lead to data leakage, but also greatly affect the accuracy of SS. In order to improve the utilization of underwater spectrum and avoid attack, an underwater spectrum sensing model based on the two-threshold energy detection method and K of M fusion decision method is established. Then, the trust mechanism based on beta function and XOR operation are proposed to combat individual attack and multi-user joint attack (MUJA) respectively. Finally, simulation result shows the effectiveness of these methods.
2021-10-04
Yadav, Mohini, Shankar, Deepak, Jose, Tom.  2020.  Functional Safety for Braking System through ISO 26262, Operating System Security and DO 254. 2020 AIAA/IEEE 39th Digital Avionics Systems Conference (DASC). :1–8.
This paper presents an introduction to functional safety through ISO 26262 focusing on system, software and hardware possible failures that bring security threats and discussion on DO 254. It discusses the approach to bridge the gap between different other hazard level and system ability to identify the particular fault and resolve it minimum time span possible. Results are analyzed by designing models to check and avoid all the failures, loophole prior development.
2021-06-30
Solomon Doss, J. Kingsleen, Kamalakkannan, S..  2020.  IoT System Accomplishment using BlockChain in Validating and Data Security with Cloud. 2020 Fourth International Conference on I-SMAC (IoT in Social, Mobile, Analytics and Cloud) (I-SMAC). :60—64.
In a block channel IoT system, sensitive details can be leaked by means of the proof of work or address check, as data or application Validation data is applied on the blockchain. In this, the zero-knowledge evidence is applied to a smart metering system to show how to improve the anonymity of the blockchain for privacy safety without disclosing information as a public key. Within this article, a blockchain has been implemented to deter security risks such as data counterfeiting by utilizing intelligent meters. Zero-Knowledge Proof, an anonymity blockchain technology, has been implemented through block inquiry to prevent threats to security like personal information infringement. It was suggested that intelligent contracts would be used to avoid falsification of intelligent meter data and abuse of personal details.
2021-04-27
Altarawneh, A., Skjellum, A..  2020.  The Security Ingredients for Correct and Byzantine Fault-tolerant Blockchain Consensus Algorithms. 2020 International Symposium on Networks, Computers and Communications (ISNCC). :1—9.

The blockchain technology revolution and the use of blockchains in various applications have resulted in many companies and programmers developing and customizing specific fit-for-purpose consensus algorithms. Security and performance are determined by the chosen consensus algorithm; hence, the reliability and security of these algorithms must be assured and tested, which requires an understanding of all the security assumptions that make such algorithms correct and byzantine fault-tolerant.This paper studies the "security ingredients" that enable a given consensus algorithm to achieve safety, liveness, and byzantine fault tolerance (BFT) in both permissioned and permissionless blockchain systems. The key contributions of this paper are the organization of these requirements and a new taxonomy that describes the requirements for security. The CAP Theorem is utilized to explain important tradeoffs between consistency and availability in consensus algorithm design, which are crucial depending on the specific application of a given algorithm. This topic has also been explored previously by De Angelis. However, this paper expands that prior explanation and dilemma of consistency vs. availability and then combines this with Buterin's Trilemma to complete the overall exposition of tradeoffs.

2021-02-03
Rehan, S., Singh, R..  2020.  Industrial and Home Automation, Control, Safety and Security System using Bolt IoT Platform. 2020 International Conference on Smart Electronics and Communication (ICOSEC). :787—793.
This paper describes a system that comprises of control, safety and security subsystem for industries and homes. The entire system is based on the Bolt IoT platform. Using this system, the user can control the devices such as LEDs, speed of the fan or DC motor, monitor the temperature of the premises with an alert sub-system for critical temperatures through SMS and call, monitor the presence of anyone inside the premises with an alert sub-system about any intrusion through SMS and call. If the system is used specifically in any industry then instead of monitoring the temperature any other physical quantity, which is critical for that industry, can be monitored using suitable sensors. In addition, the cloud connectivity is provided to the system using the Bolt IoT module and temperature data is sent to the cloud where using machine-learning algorithm the future temperature is predicted to avoid any accidents in the future.
2021-09-01
Hardin, David S..  2020.  Verified Hardware/Software Co-Assurance: Enhancing Safety and Security for Critical Systems. 2020 IEEE International Systems Conference (SysCon). :1—6.
Experienced developers of safety-critical and security-critical systems have long emphasized the importance of applying the highest degree of scrutiny to a system's I/O boundaries. From a safety perspective, input validation is a traditional “best practice.” For security-critical architecture and design, identification of the attack surface has emerged as a primary analysis technique. One of our current research focus areas concerns the identification of and mitigation against attacks along that surface, using mathematically-based tools. We are motivated in these efforts by emerging application areas, such as assured autonomy, that feature a high degree of network connectivity, require sophisticated algorithms and data structures, are subject to stringent accreditation/certification, and encourage hardware/software co-design approaches. We have conducted several experiments employing a state-of-the-art toolchain, due to Russinoff and O'Leary, and originally designed for use in floating-point hardware verification, to determine its suitability for the creation of safety-critical/security-critical input filters. We focus first on software implementation, but extending to hardware as well as hardware/software co-designs. We have implemented a high-assurance filter for JSON-formatted data used in an Unmanned Aerial Vehicle (UAV) application. Our JSON filter is built using a table-driven lexer/parser, supported by mathematically-proven lexer and parser table generation technology, as well as verified data structures. Filter behavior is expressed in a subset of Algorithmic C, which defines a set of C++ header files providing support for hardware design, including the peculiar bit widths utilized in that discipline, and enables compilation to both hardware and software platforms. The Russinoff-O'Leary Restricted Algorithmic C (RAC) toolchain translates Algorithmic C source to the Common Lisp subset supported by the ACL2 theorem prover; once in ACL2, filter behavior can be mathematically verified. We describe how we utilize RAC to translate our JSON filter to ACL2, present proofs of correctness for its associated data types, and describe validation and performance results obtained through the use of concrete test vectors.
2021-02-03
Razin, Y. S., Feigh, K. M..  2020.  Hitting the Road: Exploring Human-Robot Trust for Self-Driving Vehicles. 2020 IEEE International Conference on Human-Machine Systems (ICHMS). :1—6.

With self-driving cars making their way on to our roads, we ask not what it would take for them to gain acceptance among consumers, but what impact they may have on other drivers. How they will be perceived and whether they will be trusted will likely have a major effect on traffic flow and vehicular safety. This work first undertakes an exploratory factor analysis to validate a trust scale for human-robot interaction and shows how previously validated metrics and general trust theory support a more complete model of trust that has increased applicability in the driving domain. We experimentally test this expanded model in the context of human-automation interaction during simulated driving, revealing how using these dimensions uncovers significant biases within human-robot trust that may have particularly deleterious effects when it comes to sharing our future roads with automated vehicles.

2020-03-09
Perner, Cora, Kinkelin, Holger, Carle, Georg.  2019.  Adaptive Network Management for Safety-Critical Systems. 2019 IFIP/IEEE Symposium on Integrated Network and Service Management (IM). :25–30.
Present networks within safety-critical systems rely on complex and inflexible network configurations. New technologies such as software-defined networking are more dynamic and offer more flexibility, but due care needs to be exercised to ensure that safety and security are not compromised by incorrect configurations. To this end, this paper proposes the use of pre-generated and optimized configuration templates. These provide alternate routes for traffic considering availability, resilience and timing constraints where network components fail due to attacks or faults.To obtain these templates, two heuristics based on Dijkstra's algorithm and an optimization algorithm providing the maximum resilience were investigated. While the configurations obtained through optimization yield appropriate templates, the heuristics investigated are not suitable to obtain configuration templates, since they cannot fulfill all requirements.
2019-08-05
Ahmad, F., Adnane, A., KURUGOLLU, F., Hussain, R..  2019.  A Comparative Analysis of Trust Models for Safety Applications in IoT-Enabled Vehicular Networks. 2019 Wireless Days (WD). :1-8.
Vehicular Ad-hoc NETwork (VANET) is a vital transportation technology that facilitates the vehicles to share sensitive information (such as steep-curve warnings and black ice on the road) with each other and with the surrounding infrastructure in real-time to avoid accidents and enable comfortable driving experience.To achieve these goals, VANET requires a secure environment for authentic, reliable and trusted information dissemination among the network entities. However, VANET is prone to different attacks resulting in the dissemination of compromised/false information among network nodes. One way to manage a secure and trusted network is to introduce trust among the vehicular nodes. To this end, various Trust Models (TMs) are developed for VANET and can be broadly categorized into three classes, Entity-oriented Trust Models (ETM), Data oriented Trust Models (DTM) and Hybrid Trust Models (HTM). These TMs evaluate trust based on the received information (data), the vehicle (entity) or both through different mechanisms. In this paper, we present a comparative study of the three TMs. Furthermore, we evaluate these TMs against the different trust, security and quality-of-service related benchmarks. Simulation results revealed that all these TMs have deficiencies in terms of end-to-end delays, event detection probabilities and false positive rates. This study can be used as a guideline for researchers to design new efficient and effective TMs for VANET.
2020-06-22
Van, Luu Xuan, Hong Dung, Luu.  2019.  Constructing a Digital Signature Algorithm Based on the Difficulty of Some Expanded Root Problems. 2019 6th NAFOSTED Conference on Information and Computer Science (NICS). :190–195.
This paper presents the proposed method of building a digital signature algorithm which is based on the difficulty of solving root problem and some expanded root problems on Zp. The expanded root problem is a new form of difficult problem without the solution, also originally proposed and applied to build digital signature algorithms. This proposed method enable to build a high-security digital signature platform for practical applications.
2020-02-17
Papakonstantinou, Nikolaos, Linnosmaa, Joonas, Alanen, Jarmo, Bashir, Ahmed Z., O'Halloran, Bryan, Van Bossuyt, Douglas L..  2019.  Early Hybrid Safety and Security Risk Assessment Based on Interdisciplinary Dependency Models. 2019 Annual Reliability and Maintainability Symposium (RAMS). :1–7.
Safety and security of complex critical infrastructures are very important for economic, environmental and social reasons. The complexity of these systems introduces difficulties in the identification of safety and security risks that emerge from interdisciplinary interactions and dependencies. The discovery of safety and security design weaknesses late in the design process and during system operation can lead to increased costs, additional system complexity, delays and possibly undesirable compromises to address safety and security weaknesses.
2020-09-28
Evans, David, Calvo, Daniel, Arroyo, Adrian, Manilla, Alejandro, Gómez, David.  2019.  End-to-end security assessment framework for connected vehicles. 2019 22nd International Symposium on Wireless Personal Multimedia Communications (WPMC). :1–6.
To increase security and to offer user experiences according to the requirements of a hyper-connected world, modern vehicles are integrating complex electronic systems, being transformed into systems of Cyber-Physical Systems (CPS). While a great diversity of heterogeneous hardware and software components must work together and control in real-time crucial functionalities, cybersecurity for the automotive sector is still in its infancy. This paper provides an analysis of the most common vulnerabilities and risks of connected vehicles, using a real example based on industrial and market-ready technologies. Several components have been implemented to inject and simulate multiple attacks, which enable security services and mitigation actions to be developed and validated.
2020-07-27
Liem, Clifford, Murdock, Dan, Williams, Andrew, Soukup, Martin.  2019.  Highly Available, Self-Defending, and Malicious Fault-Tolerant Systems for Automotive Cybersecurity. 2019 IEEE 19th International Conference on Software Quality, Reliability and Security Companion (QRS-C). :24–27.
With the growing number of electronic features in cars and their connections to the cloud, smartphones, road-side equipment, and neighboring cars the need for effective cybersecurity is paramount. Beyond the concern of brand degradation, warranty fraud, and recalls, what keeps manufacturers up at night is the threat of malicious attacks which can affect the safety of vehicles on the road. Would any single protection technique provide the security needed over the long lifetime of a vehicle? We present a new methodology for automotive cybersecurity where the designs are made to withstand attacks in the future based on the concepts of high availability and malicious fault-tolerance through self-defending techniques. When a system has an intrusion, self-defending technologies work to contain the breach using integrity verification, self-healing, and fail-over techniques to keep the system running.
2020-03-02
Zheng, Zhengfan, Zheng, Bo, Wu, Yuechao, Chen, Shangui.  2019.  An Integrated Safety Management System Based on Ubiquitous Internet of Things in Electricity for Smart Pumped-storage Power Stations. 2019 4th International Conference on Intelligent Green Building and Smart Grid (IGBSG). :548–551.
The safety management is an important and fundamental task in the construction and operation of pumped-storage power stations. However, because of the traditional technical framework, the relevant systems are separated from each other, leading to a lot of disadvantages in application and performance. In order to meet the requirements of smart pumped-storage power stations, an integrated safety management system (ISMS) based on ubiquitous internet of things in electricity is proposed in this paper. The ISMS is divided into five layers including data display layer, data manipulation layer, data processing layer, data transmission layer and data acquisition layer. It consists of six modules, i.e., central control module, cave access control and personnel location module, video and security monitoring module, emergency broadcasting and communication module, geological warning module, and fall protection module. All modules are integrated into a unified information platform.
2022-04-20
Venkataramanan, Venkatesh, Srivastava, Anurag K., Hahn, Adam, Zonouz, Saman.  2019.  Measuring and Enhancing Microgrid Resiliency Against Cyber Threats. IEEE Transactions on Industry Applications. 55:6303—6312.
Recent cyber attacks on the power grid have been of increasing complexity and sophistication. In order to understand the impact of cyber-attacks on the power system resiliency, it is important to consider an holistic cyber-physical system specially with increasing industrial automation. In this study, device-level resilience properties of the various controllers and their impact on the microgrid resiliency is studied. In addition, a cyber-physical resiliency metric considering vulnerabilities, system model, and device-level properties is proposed. Resiliency is defined as the system ability to provide energy to critical loads even in extreme contingencies and depends on system ability to withstand, predict, and recover. A use case is presented inspired by the recent Ukraine cyber-attack. A use case has been presented to demonstrate application of the developed cyber-physical resiliency metric to enhance situational awareness of the operator, and enable better proactive or remedial control actions to improve resiliency.
2020-07-06
Brezhniev, Yevhen.  2019.  Multilevel Fuzzy Logic-Based Approach for Critical Energy Infrastructure’s Cyber Resilience Assessment. 2019 10th International Conference on Dependable Systems, Services and Technologies (DESSERT). :213–217.
This paper presents approach for critical energy infrastructure's (CEI) cyber resilience assessment. The CEI is the vital physical system of systems, whose accidents and failures lead to damage of economy, environment, impact on health and lives of people. The analysis of cyber incidents with Ukrainian CEI confirms the importance of the task of increasing its cyber resilience to external hostile influences and keeping of the appropriate level of functionality, safety and reliability. This paper is devoted to development of approach for CEI's cyber resilience assessment considering the important capacities of its systems (adaptivity, restoration, absorbability, preventive) and interdependencies between them. This approach is based on application of multilevel fuzzy logic models (called as logic-linguistic models, LLM) taking into consideration the data available from expert's knowledge. The comparison between risk management and resilience assurance is performed. The new risk-oriented definition of resiliency is suggested.
2020-03-16
Lin, Kuo-Sui.  2019.  A New Evaluation Model for Information Security Risk Management of SCADA Systems. 2019 IEEE International Conference on Industrial Cyber Physical Systems (ICPS). :757–762.
Supervisory control and data acquisition (SCADA) systems are becoming increasingly susceptible to cyber-physical attacks on both physical and cyber layers of critical information infrastructure. Failure Mode and Effects Analysis (FMEA) have been widely used as a structured method to prioritize all possible vulnerable areas (failure modes) for design review of security of information systems. However, traditional RPN based FMEA has some inherent problems. Besides, there is a lacking of application of FMEA for security in SCADAs under vague and uncertain environment. Thus, the main purpose of this study was to propose a new evaluation model, which not only intends to recover above mentioned problems, but also intends to evaluate, prioritize and correct security risk of SCADA system's threat modes. A numerical case study was also conducted to demonstrate that the proposed new evaluation model is not only capable of addressing FMEA's inherent problems but also is best suited for a semi-quantitative high level analysis of a secure SCADA's failure modes in the early design phases.
2022-04-20
Ratasich, Denise, Khalid, Faiq, Geissler, Florian, Grosu, Radu, Shafique, Muhammad, Bartocci, Ezio.  2019.  A Roadmap Toward the Resilient Internet of Things for Cyber-Physical Systems. IEEE Access. 7:13260–13283.
The Internet of Things (IoT) is a ubiquitous system connecting many different devices - the things - which can be accessed from the distance. The cyber-physical systems (CPSs) monitor and control the things from the distance. As a result, the concepts of dependability and security get deeply intertwined. The increasing level of dynamicity, heterogeneity, and complexity adds to the system's vulnerability, and challenges its ability to react to faults. This paper summarizes the state of the art of existing work on anomaly detection, fault-tolerance, and self-healing, and adds a number of other methods applicable to achieve resilience in an IoT. We particularly focus on non-intrusive methods ensuring data integrity in the network. Furthermore, this paper presents the main challenges in building a resilient IoT for the CPS, which is crucial in the era of smart CPS with enhanced connectivity (an excellent example of such a system is connected autonomous vehicles). It further summarizes our solutions, work-in-progress and future work to this topic to enable ``Trustworthy IoT for CPS''. Finally, this framework is illustrated on a selected use case: a smart sensor infrastructure in the transport domain.
Conference Name: IEEE Access
2020-07-24
Chen, Jun, Zhu, Huijun, Chen, Zhixin, Cai, Xiaobo, Yang, Linnan.  2019.  A Security Evaluation Model Based on Fuzzy Hierarchy Analysis for Industrial Cyber-Physical Control Systems. 2019 IEEE International Conference on Industrial Internet (ICII). :62—65.
With the increasing security threats to the information of Industrial Cyber-physical Control Systems, the quantitative assessment of security risk becomes an important basis of information security research. Based on fuzzy hierarchy analysis, this paper constructs the hierarchical model of industrial control system safety risk evaluation, and obtains the exact value of risk. Experimental results show that the proposed method can effectively quantify the control system risk, which provides a basis for industrial control system risk management decision.
2020-02-17
Zheng-gang, He, Jing-ni, Guo.  2019.  Security Risk Assessment of Multimodal Transport Network Based on WBS-RBS and PFWA Operator. 2019 4th International Conference on Intelligent Transportation Engineering (ICITE). :203–206.
In order to effectively assess the security risks in multimodal transport networks, a security risk assessment method based on WBS-RBS and Pythagorean Fuzzy Weighted Average (PFWA) operator is proposed. The risk matrix 0-1 assignment of WBS-RBS is replaced by the Pythagorean Fuzzy Number (PFLN) scored by experts. The security risk ranking values of multimodal transport network are calculated from two processes of whole-stage and phased, respectively, and the security risk assessment results are obtained. Finally, an example of railway-highway-waterway intermodal transportation process of automobile parts is given to verify the validity of the method, the results show that the railway transportation is more stable than the waterway transportation, and the highway transportation has the greatest security risk, and for different security risk factors, personnel risk has the greatest impact. The risk of goods will change with the change of the attributes of goods, and the security risk of storage facilities is the smallest.
2020-11-16
Mailloux, L. O., Span, M., Mills, R. F., Young, W..  2019.  A Top Down Approach for Eliciting Systems Security Requirements for a Notional Autonomous Space System. 2019 IEEE International Systems Conference (SysCon). :1–7.
Today's highly interconnected and technology reliant environment places great emphasis on the need for secure cyber-physical systems. This work addresses this need by detailing a top down systems security requirements analysis approach for understanding and eliciting security requirements for a notional space system. More specifically, the System-Theoretic Process Analysis approach for Security (STPA-Sec) is used to understand and elicit systems security requirements during the conceptual stage of development. This work employs STPA-Sec in a notional space system to detail the development of functional-level security requirements, design-level engineering considerations, and architectural-level security specifications early in the system life cycle when the solution trade-space is largest rather than merely examining components and adding protections during system operation, maintenance, or sustainment. Lastly, this approach employs a holistic viewpoint which aligns with the systems and software engineering processes as detailed in ISO/IEC/IEEE 152SS and NIST SP SOO-160 Volume 1. This work seeks to advance the science of systems security by providing insight into a viable systems security requirements analysis approach which results in traceable security, safety, and resiliency requirements that can be designed-for, built-to, and verified with confidence.
2020-02-10
Chechik, Marsha.  2019.  Uncertain Requirements, Assurance and Machine Learning. 2019 IEEE 27th International Requirements Engineering Conference (RE). :2–3.
From financial services platforms to social networks to vehicle control, software has come to mediate many activities of daily life. Governing bodies and standards organizations have responded to this trend by creating regulations and standards to address issues such as safety, security and privacy. In this environment, the compliance of software development to standards and regulations has emerged as a key requirement. Compliance claims and arguments are often captured in assurance cases, with linked evidence of compliance. Evidence can come from testcases, verification proofs, human judgement, or a combination of these. That is, we try to build (safety-critical) systems carefully according to well justified methods and articulate these justifications in an assurance case that is ultimately judged by a human. Yet software is deeply rooted in uncertainty making pragmatic assurance more inductive than deductive: most of complex open-world functionality is either not completely specifiable (due to uncertainty) or it is not cost-effective to do so, and deductive verification cannot happen without specification. Inductive assurance, achieved by sampling or testing, is easier but generalization from finite set of examples cannot be formally justified. And of course the recent popularity of constructing software via machine learning only worsens the problem - rather than being specified by predefined requirements, machine-learned components learn existing patterns from the available training data, and make predictions for unseen data when deployed. On the surface, this ability is extremely useful for hard-to specify concepts, e.g., the definition of a pedestrian in a pedestrian detection component of a vehicle. On the other, safety assessment and assurance of such components becomes very challenging. In this talk, I focus on two specific approaches to arguing about safety and security of software under uncertainty. The first one is a framework for managing uncertainty in assurance cases (for "conventional" and "machine-learned" systems) by systematically identifying, assessing and addressing it. The second is recent work on supporting development of requirements for machine-learned components in safety-critical domains.