Biblio
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.
Safety and security of complex critical infrastructures is very important for economic, environmental and social reasons. The interdisciplinary and inter-system dependencies within these infrastructures introduce difficulties in the safety and security design. Late discovery of safety and security design weaknesses can lead to increased costs, additional system complexity, ineffective mitigation measures and delays to the deployment of the systems. Traditionally, safety and security assessments are handled using different methods and tools, although some concepts are very similar, by specialized experts in different disciplines and are performed at different system design life-cycle phases.The methodology proposed in this paper supports a concurrent safety and security Defense in Depth (DiD) assessment at an early design phase and it is designed to handle safety and security at a high level and not focus on specific practical technologies. It is assumed that regardless of the perceived level of security defenses in place, a determined (motivated, capable and/or well-funded) attacker can find a way to penetrate a layer of defense. While traditional security research focuses on removing vulnerabilities and increasing the difficulty to exploit weaknesses, our higher-level approach focuses on how the attacker's reach can be limited and to increase the system's capability for detection, identification, mitigation and tracking. The proposed method can assess basic safety and security DiD design principles like Redundancy, Physical separation, Functional isolation, Facility functions, Diversity, Defense lines/Facility and Computer Security zones, Safety classes/Security Levels, Safety divisions and physical gates/conduits (as defined by the International Atomic Energy Agency (IAEA) and international standards) concurrently and provide early feedback to the system engineer. A prototype tool is developed that can parse the exported project file of the interdisciplinary model. Based on a set of safety and security attributes, the tool is able to assess aspects of the safety and security DiD capabilities of the design. Its results can be used to identify errors, improve the design and cut costs before a formal human expert inspection. The tool is demonstrated on a case study of an early conceptual design of a complex system of a nuclear power plant.
Remote patient monitoring is a system that focuses on patients care and attention with the advent of the Internet of Things (IoT). The technology makes it easier to track distance, but also to diagnose and provide critical attention and service on demand so that billions of people are safer and more safe. Skincare monitoring is one of the growing fields of medical care which requires IoT monitoring, because there is an increasing number of patients, but cures are restricted to the number of available dermatologists. The IoT-based skin monitoring system produces and store volumes of private medical data at the cloud from which the skin experts can access it at remote locations. Such large-scale data are highly vulnerable and otherwise have catastrophic results for privacy and security mechanisms. Medical organizations currently do not concentrate much on maintaining safety and privacy, which are of major importance in the field. This paper provides an IoT based skin surveillance system based on a blockchain data protection and safety mechanism. A secure data transmission mechanism for IoT devices used in a distributed architecture is proposed. Privacy is assured through a unique key to identify each user when he registers. The principle of blockchain also addresses security issues through the generation of hash functions on every transaction variable. We use blockchain consortiums that meet our criteria in a decentralized environment for controlled access. The solutions proposed allow IoT based skin surveillance systems to privately and securely store and share medical data over the network without disturbance.
Heterogeneous system-on-chip platforms with multiple processing cores are becoming increasingly common in safety-and security-critical embedded systems. To facilitate a logical isolation of physically connected on-chip components, internal communication links of such platforms are often equipped with dedicated access protection units. When performed manually, however, the configuration of these units can be both time-consuming and error-prone. To resolve this issue, we present a formal model and a corresponding design methodology that allows developers to specify access permissions and information flow requirements for embedded systems in a mostly platform-independent manner. As part of the methodology, the consistency between the permissions and the requirements is automatically verified and an extensible generation framework is used to transform the abstract permission declarations into configuration code for individual access protection units. We present a prototypical implementation of this approach and validate it by generating configuration code for the access protection unit of a commercially available multiprocessor system-on-chip.
The next generation of dependable embedded systems feature autonomy and higher levels of interconnection. Autonomy is commonly achieved with the support of artificial intelligence algorithms that pose high computing demands on the hardware platform, reaching a high performance scale. This involves a dramatic increase in software and hardware complexity, fact that together with the novelty of the technology, raises serious concerns regarding system dependability. Traditional approaches for certification require to demonstrate that the system will be acceptably safe to operate before it is deployed into service. The nature of autonomous systems, with potentially infinite scenarios, configurations and unanticipated interactions, makes it increasingly difficult to support such claim at design time. In this context, the extended networking technologies can be exploited to collect post-deployment evidence that serve to oversee whether safety assumptions are preserved during operation and to continuously improve the system through regular software updates. These software updates are not only convenient for critical bug fixing but also necessary for keeping the interconnected system resilient against security threats. However, such approach requires a recondition of the traditional certification practices.