Systematizing Decentralization and Privacy: Lessons from 15 Years of Research and Deployments

Decentralized systems are a subset of distributed systems where multiple authorities control different components and no authority is fully trusted by all. This implies that any component in a decentralized system is potentially adversarial. We revise fifteen years of research on decentralization and privacy, and provide an overview of key systems, as well as key insights for designers of future systems. We show that decentralized designs can enhance privacy, integrity, and availability but also require careful trade-offs in terms of system complexity, properties provided, and degree of decentralization. These trade-offs need to be understood and navigated by designers. We argue that a combination of insights from cryptography, distributed systems, and mechanism design, aligned with the development of adequate incentives, are necessary to build scalable and successful privacy-preserving decentralized systems

Blockchain-Enabled Energy Trading Platforms: Reviewing Current Implementations, Challenges, and Future Prospects

Blockchain-enabled energy trading platforms have emerged as promising solutions for transforming traditional energy markets by enabling peer-to-peer (P2P) energy transactions and decentralized energy management. This abstract provides an overview of current implementations, challenges, and future prospects of blockchain-enabled energy trading platforms. Blockchain technology, known for its decentralized and immutable ledger system, offers several advantages for energy trading applications. By leveraging blockchain's transparency, security, and trustworthiness, energy trading platforms enable direct transactions between producers and consumers, bypassing intermediaries and reducing transaction costs. Moreover, blockchain facilitates the integration of renewable energy resources, demand response mechanisms, and smart grid technologies, fostering a more resilient and sustainable energy ecosystem. Several blockchain-enabled energy trading platforms have been deployed worldwide, showcasing diverse use cases and operational models. Platforms such as Power Ledger, Grid+, and WePower facilitate P2P energy trading among prosumers (producer-consumers) within microgrids or virtual power plants, empowering individuals and communities to monetize their excess energy generation and optimize their energy consumption patterns. These platforms utilize blockchain-based smart contracts to automate energy transactions, ensure transparent billing, and enable real-time settlement, enhancing efficiency and accountability in energy markets. Despite the potential benefits, blockchain-enabled energy trading platforms face several challenges and limitations. Scalability and throughput constraints of blockchain networks, interoperability issues among different blockchain protocols, and regulatory uncertainties pose significant barriers to widespread adoption. Moreover, the integration of physical energy infrastructure with blockchain technology requires robust cybersecurity measures to protect against cyber threats and ensure the integrity and reliability of energy transactions. Looking ahead, the future prospects of blockchain-enabled energy trading platforms are promising, with opportunities for innovation and growth. Advances in blockchain scalability solutions, such as sharding and layer-2 scaling solutions, hold potential for addressing scalability challenges and enabling large-scale deployment of energy trading platforms. Moreover, the emergence of interoperability protocols and industry standards, coupled with regulatory frameworks conducive to blockchain adoption, can foster greater interoperability and regulatory clarity in energy markets

Software Defined Networks based Smart Grid Communication: A Comprehensive Survey

The current power grid is no longer a feasible solution due to ever-increasing user demand of electricity, old infrastructure, and reliability issues and thus require transformation to a better grid a.k.a., smart grid (SG). The key features that distinguish SG from the conventional electrical power grid are its capability to perform two-way communication, demand side management, and real time pricing. Despite all these advantages that SG will bring, there are certain issues which are specific to SG communication system. For instance, network management of current SG systems is complex, time consuming, and done manually. Moreover, SG communication (SGC) system is built on different vendor specific devices and protocols. Therefore, the current SG systems are not protocol independent, thus leading to interoperability issue. Software defined network (SDN) has been proposed to monitor and manage the communication networks globally. This article serves as a comprehensive survey on SDN-based SGC. In this article, we first discuss taxonomy of advantages of SDNbased SGC.We then discuss SDN-based SGC architectures, along with case studies. Our article provides an in-depth discussion on routing schemes for SDN-based SGC. We also provide detailed survey of security and privacy schemes applied to SDN-based SGC. We furthermore present challenges, open issues, and future research directions related to SDN-based SGC.Comment: Accepte

Decentralized Federated Learning: Fundamentals, State-of-the-art, Frameworks, Trends, and Challenges

In the last decade, Federated Learning (FL) has gained relevance in training collaborative models without sharing sensitive data. Since its birth, Centralized FL (CFL) has been the most common approach in the literature, where a central entity creates a global model. However, a centralized approach leads to increased latency due to bottlenecks, heightened vulnerability to system failures, and trustworthiness concerns affecting the entity responsible for the global model creation. Decentralized Federated Learning (DFL) emerged to address these concerns by promoting decentralized model aggregation and minimizing reliance on centralized architectures. However, despite the work done in DFL, the literature has not (i) studied the main aspects differentiating DFL and CFL; (ii) analyzed DFL frameworks to create and evaluate new solutions; and (iii) reviewed application scenarios using DFL. Thus, this article identifies and analyzes the main fundamentals of DFL in terms of federation architectures, topologies, communication mechanisms, security approaches, and key performance indicators. Additionally, the paper at hand explores existing mechanisms to optimize critical DFL fundamentals. Then, the most relevant features of the current DFL frameworks are reviewed and compared. After that, it analyzes the most used DFL application scenarios, identifying solutions based on the fundamentals and frameworks previously defined. Finally, the evolution of existing DFL solutions is studied to provide a list of trends, lessons learned, and open challenges