The Industrial Internet of Things (IIoT) has been positioned as a key pillar of the Industry 4.0 revolution, which is projected to continue accelerating and realizing digital transformations. The IIoT is becoming indispensable, providing the means through which modern communication is conducted across industries and offering improved efficiency, scalability, and robustness. However, the structural and dynamic complexity introduced by the continuous integration of the IIoT has widened the scope for cyber-threats, as the processes and data generated by this integration are susceptible and vulnerable to attacks. This article presents an in-depth analysis of the state-of-the-art in the IIoT ecosystem from security and digital forensics perspectives. The dimensions of this study are twofold: first, we present an overview of the cutting-edge security of IIoT ecosystems, and second, we survey the literature on digital forensics. The key achievements, open challenges, and future directions are identified in each case. The challenges and directions for future studies that we identify will provide important guidance for cybersecurity researchers and practitioners. © 2024 Copyright held by the owner/author(s). Publication rights licensed to ACM.

The need for Renewable Energy (RE) market decentralization and its rapid growth has led to new challenges related to energy traceability and pricing. While RE has undergone remarkable growth, the traditional methods of tracking renewable energy transactions lack transparency, making it difficult to ensure the authenticity of claims related to the source and quality of energy. Blockchain has been seen as a remarkable future technology capable of being integrated across many systems on the internet. This paper proposes a blockchainenabled solution to address these challenges by providing a secure and transparent traceability and pricing model for RE. The proposed approach uses blockchain technology to record and verify all energy transactions in a decentralized and tamper-proof manner. Additionally, the approach suggests the incorporation of smart contracts and Crypto-based Arbitrage techniques to automate the pricing of RE and the exploitation of a fair and efficient pricing mechanism. The paper goes the extra mile and presents an RE-based hypothetical case scenario that illustrates the implementation of the proposed model in an RE market while highlighting the benefits of using blockchain technology for energy traceability and pricing. The culminating discussions show that the blockchain-enabled RE traceability and pricing model offers a secure, transparent, and efficient pricing solution that can enhance trust in the RE market while promoting the transition to a sustainable energy future. © 2023 IEEE.

The digital market trend is rapidly expanding due to key characteristics like decentralization, accessibility, and market diversity enabled by blockchain technology. This study proposes a Predictive Analytics System to provide simplified reporting for the three most popular cryptocurrencies with varying digits, namely ADA Cardano, Ethereum, and Binance coin, for ten days to contribute to this emerging technology. Thus, this proposed system employs a data science-based framework and six highly advanced data-driven Machine learning and Deep learning algorithms: Support Vector Regressor, Auto-Regressive Integrated Moving Average (ARIMA), Facebook Prophet, Unidirectional LSTM, Bidirectional LSTM, Stacked LSTM. Moreover, the research experiments are repeated several times to achieve the best results by employing hyperparameter tuning of each algorithm. This involves selecting an appropriate kernel and suitable data normalization technique for SVR, determining ARIMA's (p, d, q) values, and optimizing the loss function values, number of neurons, hidden layers, and epochs in LSTM models. For the model validation, we utilize widely used evaluation techniques: Mean Absolute Error, Root Mean Squared Error, Mean Absolute Percentage Error, and R-squared. Results demonstrate that ARIMA outperforms the other models in all cases, accurately projecting the price variability within the actual price range. Conversely, Facebook Prophet exhibits good performance to some extent. The paper suggests that the ARIMA technique offers practical implications for market analysts, enabling them to make well-informed decisions based on accurate price projections. © 2013 IEEE.

The aim of this thesis is to advance the knowledge on the efficient design and evaluation of distributed marketplaces with an emphasis on trust and privacy. Distributed systems are an integral part of today's computing infrastructures, enabling multiple nodes to work towards a common goal. Although distributed, most of today's computational systems are still built with a centralized architecture, which assumes complete governance by a single organization. In the case of centralized marketplaces, the correct trade execution guarantees, \ie digital trust, and data privacy are provided centrally, containing all processes and operations within a single organization's boundaries. This puts the marketplace operator in a prime position to govern trade settlement conditions. However, trust issues are raised if more than one organization has to govern the marketplace. In such a case, trust and privacy are decentralized, and control is distributed among all organizations which are part of the marketplace system. Thus, a decentralized marketplace requires a robust and secure consensus mechanism, which enables digital trust while allowing organizations to process and store private data for further usage in trade settlements. 

This thesis investigates both centralized and decentralized marketplace architectures applied to use cases of AI artifacts and renewable energy trading. It begins with a study of a marketplace for Artificial Intelligence (AI) artifacts where multiple organizations collaborate on AI pipeline execution. The study defines a Secure Virtual Premise, which enables AI pipeline execution in a centralized marketplace governed by a trusted third party. The thesis continues with a survey of the telecommunication services marketplaces, where both centralized and decentralized architectures are discussed. In addition, the survey provides an in-depth investigation of blockchain technology as a main trust-enabling platform, providing distributed storage and data assurance to all processes in a decentralized marketplace. Having mapped the state-of-the-art, the research shifts towards an in-depth investigation of blockchain-based decentralized renewable energy marketplaces. The main aim of such a marketplace is to incentivize the widespread adoption of renewable energy sources, resulting in the decarbonization of electricity distribution systems. The designed marketplace enables automation and trusted execution of peer-to-peer (P2P) energy trade settlements in decentralized systems while preserving users' data privacy. Furthermore, the marketplace is aligned with the data and P2P energy trade regulations. The studies provide an in-depth requirements definition, system architecture, implementation, and performance evaluation of marketplaces based on two major blockchain platforms. The final study of this thesis provides the improvements towards the renewable energy marketplace model aiming at an enhancement of trust, privacy, and scalability.

Renewable energy sources were introduced as an alternative to fossil fuel sources to make electricity generation cleaner. However, today's renewable energy markets face a number of limitations, such as inflexible pricing models and inaccurate consumption information. These limitations can be addressed with a decentralized marketplace architecture. Such architecture requires a mechanism to guarantee that all marketplace operations are executed according to predefined rules and regulations. One of the ways to establish such a mechanism is blockchain technology. This work defines a decentralized blockchain-based peer-to-peer (P2P) energy marketplace which addresses actors' privacy and the performance of consensus mechanisms. The defined marketplace utilizes private permissioned Ethereum-based blockchain client Hyperledger Besu (HB) and its smart contracts to automate the P2P trade settlement process. Also, to make the marketplace compliant with energy trade regulations, it includes the regulator actor, which manages the issue and consumption of guarantees of origin and certifies the renewable energy sources used to generate traded electricity. Finally, the proposed marketplace incorporates privacy-preserving features, allowing it to generate private transactions and store them within a designated group of actors. Performance evaluation results of HB-based marketplace with three main consensus mechanisms for private networks, i.e., Clique, IBFT 2.0, and QBFT, demonstrate a lower throughput than another popular private permissioned blockchain platform Hyperledger Fabric (HF). However, the lower throughput is a side effect of the Byzantine Fault Tolerant characteristics of HB's consensus mechanisms, i.e., IBFT 2.0 and QBFT, which provide increased security compared to HF's Crash Fault Tolerant consensus RAFT.

This work defines a decentralized blockchain-based peer-to-peer (P2P) energy marketplace which addresses actors' privacy and the performance of consensus mechanisms. The defined marketplace utilizes private permissioned Ethereum-based blockchain client Hyperledger Besu (HB) and its smart contracts to automate the P2P trade settlement process. Also, to make the marketplace compliant with energy trade regulations, it includes the regulator actor, which manages the issue and generation of guarantees of origin and certifies the renewable energy sources used to generate traded electricity. Finally, the proposed marketplace incorporates privacy-preserving features, allowing it to generate private transactions and store them within a designated group of actors. Performance evaluation results of HB-based marketplace with three main consensus mechanisms for private networks, i. e., Clique, IBFT 2.0, and QBFT, demonstrate a lower throughput than another popular private permissioned blockchain platform Hyperledger Fabric (HF). However, the lower throughput is a side effect of the Byzantine Fault Tolerant characteristics of HB's consensus mechanisms, i. e., IBFT 2.0 and QBFT, which provide increased security compared to HF's Crash Fault Tolerant consensus RAFT. © 2023 IEEE.

Renewable energy sources are becoming increasingly important as a substitute for fossil energy production. However, distributed renewable energy production faces several challenges regarding trading and management, such as inflexible pricing models and inaccurate green consumption information. A decentralized peer-to-peer (P2P) electricity marketplace may address these challenges. It enables prosumers to market their self-produced electricity. However, such a marketplace needs to guarantee that the transactions follow market rules and government regulations, cannot be manipulated, and are consistent with the generated electricity. One of the ways to provide these guarantees is to leverage blockchain technology.

This work describes a decentralized blockchain-based P2P energy marketplace addressing privacy, trust, and governance issues. It uses a private permissioned blockchain Hyperledger Fabric (HF) and its smart contracts to perform energy trading settlements. The suggested P2P marketplace includes a particular regulator actor acting as a governmental representative overseeing marketplace operations. In this way, the suggested P2P marketplace can address the governance issues needed in electricity marketplaces. Further, the proposed marketplace ensures actors’ data privacy by employing HF’s private data collections while preserving the integrity and auditability of all operations. We present an in-depth performance evaluation and provide insights into the security and privacy challenges emerging from such a marketplace. The results demonstrate that partial centralization by the applied regulator does not limit the P2P energy trade settlement execution. Blockchain technology allows for automated marketplace operations enabling better incentives for prosumer electricity production. Finally, the suggested marketplace preserves the user’s privacy when P2P energy trade settlements are conducted.

The energy distribution infrastructure is a vital part of any modern society. Thus, renewable energy sources are becoming increasingly important as a substitute for energy produced with fossil fuels. However, renewable energy production faces several challenges in the energy market and its management, such as inflexible pricing models and inaccurate green consumption information. A decentralized electricity marketplace may address these challenges. However, such a platform must guarantee that the transactions follow the market rules and regulations, cannot be manipulated, and are consistent with the energy generated. One of the ways to provide these guarantees is to leverage blockchain technology. Our previous studies demonstrate the current energy trade regulations result in partial marketplace centralization around governmental authority. The governmental authority, i.e., the regulator, oversees marketplace operations and requires energy providers to share private data about electricity generation and energy trade settlement. This study proposes amendments to D2018/2001 legislation and the governmental regulator actor to improve marketplace flexibility and data privacy. Further, we propose a new blockchain-based P2P energy marketplace model with increased flexibility and scalability while addressing actors' privacy and trust requirements. The marketplace utilizes a private permissioned blockchain Hyperledger Fabric (HF) due to its privacy-preserving and trust-enabling capabilities. This study provides HF comparison with Ethereum-based competitor Hyperledger Besu (HB). Further, based on the identified advantages and limitations, we discuss the rationale for the choice of HF. We utilize HF's smart contracts to enable P2P energy trade settlement orchestration and management. Based on previous studies, we propose an improvement towards HF security by utilizing a Byzantine Fault Tolerant (BFT) consensus mechanism, which is protected against malicious system actors. The results demonstrate that while protecting the blockchain network from malicious system actors, the BFT mechanism shows a similar throughput to the RAFT Crash Fault Tolerant consensus in the context of the P2P energy marketplace. Finally, BFT consensus enables legislation enhancements, resulting in increased flexibility and data privacy in the energy trade marketplace.

Digital marketplaces were created recently to accelerate the delivery of applications and services to customers. Their appealing feature is to activate and dynamize the demand, supply, and development of digital goods, applications, or services. By being an intermediary between producer and consumer, the primary business model for a marketplace is to charge the producer with a commission on the amount paid by the consumer. However, most of the time, the commission is dictated by the marketplace facilitator itself and creates an imbalance in value distribution, where producer and consumer sides suffer monetarily. In order to eliminate the need for a centralized entity between the producer and consumer, a blockchain-based decentralized digital marketplace concept was introduced. It provides marketplace actors with the tools to perform business transactions in a trusted manner and without the need for an intermediary. In this work, we provide a survey on Telecommunication Services Marketplaces (TSMs) which employ blockchain technology as the main trust enabling entity in order to avoid any intermediaries. We provide an overview of scientific and industrial proposals on the blockchain-based online digital marketplaces at large, and TSMs in particular. We consider in this study the notion of telecommunication services as any service enabling the capability for information transfer and, increasingly, information processing provided to a group of users by a telecommunications system. We discuss the main standardization activities around the concepts of TSMs and provide particular use-cases for the TSM business transactions such as SLA settlement. Also, we provide insights into the main foundational services provided by the TSM, as well as a survey of the scientific and industrial proposals for such services. Finally, a prospect for future developments is given. Author