Internet of Things (IoT) systems are complex systems that can manage mission-critical, costly operations or the collection, storage, and processing of sensitive data. Therefore, security represents a primary concern that should be considered when engineering IoT systems. Additionally, several challenges need to be addressed, including the following ones. IoT systems’ environments are dynamic and uncertain. For instance, IoT devices can be mobile or might run out of batteries, so they can become suddenly unavailable. To cope with such environments, IoT systems can be engineered as goal-driven and self-adaptive systems. A goal-driven IoT system is composed of a dynamic set of IoT devices and services that temporarily connect and cooperate to achieve a specific goal. Several approaches have been proposed to engineer goal-driven and self-adaptive IoT systems. However, none of the existing approaches enable goal-driven IoT systems to automatically detect security threats and autonomously adapt to mitigate them. Toward bridging these gaps, this paper proposes a distributed architectural Approach for engineering goal-driven IoT Systems that can autonomously SElf-adapt to secuRity Threats in their environments (ASSERT). ASSERT exploits techniques and adopts notions, such as agents, federated learning, feedback loops, and blockchain, for maintaining the systems’ security and enhancing the trustworthiness of the adaptations they perform. The results of the experiments that we conducted to validate the approach’s feasibility show that it performs and scales well when detecting security threats, performing autonomous security adaptations to mitigate the threats and enabling systems’ constituents to learn about security threats in their environments collaboratively.

Blockchain has introduced new opportunities with the potential to enhance systems and services across diverse application domains. Fundamental characteristics of blockchains such as immutability, decentralisation, transparency and traceability have a profound role in this. However, integration with contemporary systems and among disparate blockchain-based applications is a non-trivial challenge primarily due to differences with respect to platforms, consensus mechanism, and governance. Although this challenge has received some attention from the research community, it requires careful analysis to analyse existing work and ascertain gaps to achieve effective and efficient solution to this challenge. This article presents a thorough systematic review of existing research within blockchain interoperability highlighting significant contributions. Leveraging this analysis, the article presents an internet-inspired framework (Chain-Net) to facilitate interoperability within blockchain-based systems whereby two systems within independent Blockchain networks can securely exchange data with each other. This is achieved by using gateway module at each network. This module is a lightweight node registered by the Blockchain network, equipped with discovery service to lookup a target blockchain, and is responsible for forwarding cross-chain transactions to gateway module at the target blockchain. Gateway module plays a vital role in the Chain-Net model, as it holds a cross-chain transaction in a pending state until a confirmation is received from the target blockchain, thus maintaining the record integrity between the two chains. The article presents our efforts to evaluate the proposed blockchain interoperability framework against success criteria based on our analysis of the blockchain interoperability challenge.

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