Embracing new technologies that could enable drastic reductions in GHG emissions will be key to delivering low-emissions pathways for growth, but it is not always obvious what the big breakthroughs will look like. This report looks at how blockchain technology can be applied to support sustainable infrastructure investment that is aligned with climate change objectives. It focuses on three key points: the financing of infrastructure initiatives, the creation of visibility and alignment of climate action, and the provisioning of awareness and access for institutions and consumers.
Cloud architecture has become a valuable solution for different applications, such as big data analytics, due to its high-degree of availability, scalability and strategic value. However, there still remain challenges in managing cloud architecture, in areas such as cloud security. In this paper, we exploit software-defined networking (SDN) and blockchain technologies to secure cloud management platforms from a networking perspective. We develop a blockchain-powered SDN-enabled networking infrastructure in which the integration between blockchain-based security and autonomy management layer and multi-controller SDN networking layer is defined to enhance the integrity of the control and management messages. Furthermore, our proposed networking infrastructure also enables the autonomous bandwidth provisioning to enhance the availability of cloud architecture. In the simulation section, we evaluate the performance of our proposed blockchain-powered SDN-enabled networking infrastructure by considering different scenarios.
Duc V. Le, Lizzy Tengana Hurtado, Adil Ahmad, Mohsen Minaei · 6 authors
The Bitcoin network has offered a new way of securely performing financial transactions over the insecure network. Nevertheless, this ability comes with the cost of storing a large (distributed) ledger, which has become unsuitable for personal devices of any kind. Although the simplified payment verification (SPV) clients can address this storage issue, a Bitcoin SPV client has to rely on other Bitcoin nodes to obtain its transaction history and the current approaches offer no privacy guarantees to the SPV clients. This work presents $T^3$, a trusted hardware-secured Bitcoin full client that supports efficient oblivious search/update for Bitcoin SPV clients without sacrificing the privacy of the clients. In this design, we leverage the trusted execution and attestation capabilities of a trusted execution environment (TEE) and the ability to hide access patterns of oblivious random access memory (ORAM) to protect SPV clients' requests from a potentially malicious server. The key novelty of $T^3$ lies in the optimizations introduced to conventional ORAM, tailored for expected SPV client usages. In particular, by making a natural assumption about the access patterns of SPV clients, we are able to propose a two-tree ORAM construction that overcomes the concurrency limitation associated with traditional ORAMs. We have implemented and tested our system using the current Bitcoin Unspent Transaction Output database. Our experiment shows that the system is feasible to be deployed in practice while providing strong privacy and security guarantees to Bitcoin SPV clients.
This article aims to clarify the meaning and operation of the rules governing the burden of proof in discrimination cases under EU law. In addition to the text of the antidiscrimination directives, it looks at the guidelines provided by the Court of Justice of the European Union and at the application of these rules at the domestic level, focusing on three Member States: Belgium, France and Ireland. Section 1 describes the basic operation of the burden of proof provision, clarifies the respective obligations it entails for claimants and respondents and highlights differences resulting from whether direct or indirect discrimination is at stake. Section 2 considers in more detail the means of evidence that can be used to establish discrimination, with particular emphasis on statistics and situation testing. Section examines the issue of complainants' access to information held by the alleged discriminator and Section 4 offers conclusions.
The uncertainties in future Bitcoin price make it difficult to accurately predict the price of Bitcoin. Accurately predicting the price for Bitcoin is therefore important for decision-making process of investors and market players in the cryptocurrency market. Using historical data from 01/01/2012 to 16/08/2019, machine learning techniques (Generalized linear model via penalized maximum likelihood, random forest, support vector regression with linear kernel, and stacking ensemble) were used to forecast the price of Bitcoin. The prediction models employed key and high dimensional technical indicators as the predictors. The performance of these techniques were evaluated using mean absolute percentage error (MAPE), root mean square error (RMSE), mean absolute error (MAE), and coefficient of determination (R-squared). The performance metrics revealed that the stacking ensemble model with two base learner (random forest and generalized linear model via penalized maximum likelihood) and support vector regression with linear kernel as meta-learner was the optimal model for forecasting Bitcoin price. The MAPE, RMSE, MAE, and R-squared values for the stacking ensemble model were 0.0191%, 15.5331 USD, 124.5508 USD, and 0.9967 respectively. These values show a high degree of reliability in predicting the price of Bitcoin using the stacking ensemble model. Accurately predicting the future price of Bitcoin will yield significant returns for investors and market players in the cryptocurrency market.
This thesis introduces a formal general framework for scaling blockchain protocols by sharding. The framework is modular and it can be adjusted for different needs or sets of assumptions. We prove that sharded protocols obtained by following our scheme (with correct modules in place) live up to the same safety and liveness guarantees as their non-sharded counterparts. The proof is general and relies on well-defined specifications of certain components. This lays the ground for simple proofs of correctness for sharded protocols obtained by following the proposed scheme. The framework is not left as an obscure specification of some high level structure; explicit use is demonstrated by applying it to shard Algorand. As part of this concrete construction, a tamper-proof mechanism to assign nodes to shards is introduced. This mechanism is constructed by using verifiable random functions and can safely withstand a powerful adaptive adversary.
Fan Zhang, Deepak Maram, Harjasleen Malvai, Steven Goldfeder · 5 authors
Thanks to the widespread deployment of TLS, users can access private data over channels with end-to-end confidentiality and integrity. What they cannot do, however, is prove to third parties the {\em provenance} of such data, i.e., that it genuinely came from a particular website. Existing approaches either introduce undesirable trust assumptions or require server-side modifications. As a result, the value of users' private data is locked up in its point of origin. Users cannot export their data with preserved integrity to other applications without help and permission from the current data holder. We propose DECO (short for \underline{dec}entralized \underline{o}racle) to address the above problems. DECO allows users to prove that a piece of data accessed via TLS came from a particular website and optionally prove statements about such data in zero-knowledge, keeping the data itself secret. DECO is the first such system that works without trusted hardware or server-side modifications. DECO can liberate data from centralized web-service silos, making it accessible to a rich spectrum of applications. To demonstrate the power of DECO, we implement three applications that are hard to achieve without it: a private financial instrument using smart contracts, converting legacy credentials to anonymous credentials, and verifiable claims against price discrimination.
The uncertainties in future Bitcoin price make it difficult to accurately\npredict the price of Bitcoin. Accurately predicting the price for Bitcoin is\ntherefore important for decision-making process of investors and market players\nin the cryptocurrency market. Using historical data from 01/01/2012 to\n16/08/2019, machine learning techniques (Generalized linear model via penalized\nmaximum likelihood, random forest, support vector regression with linear\nkernel, and stacking ensemble) were used to forecast the price of Bitcoin. The\nprediction models employed key and high dimensional technical indicators as the\npredictors. The performance of these techniques were evaluated using mean\nabsolute percentage error (MAPE), root mean square error (RMSE), mean absolute\nerror (MAE), and coefficient of determination (R-squared). The performance\nmetrics revealed that the stacking ensemble model with two base learner (random\nforest and generalized linear model via penalized maximum likelihood) and\nsupport vector regression with linear kernel as meta-learner was the optimal\nmodel for forecasting Bitcoin price. The MAPE, RMSE, MAE, and R-squared values\nfor the stacking ensemble model were 0.0191%, 15.5331 USD, 124.5508 USD, and\n0.9967 respectively. These values show a high degree of reliability in\npredicting the price of Bitcoin using the stacking ensemble model. Accurately\npredicting the future price of Bitcoin will yield significant returns for\ninvestors and market players in the cryptocurrency market.\n
Summary With the increasing popularity of blockchain technologies in recent years, blockchain‐based decentralized applications (DApps for short in this paper) have been rapidly developed and widely adopted in many areas, being a hot topic in both academia and industry. Despite of the importance of DApps, we still have quite little understanding of DApps along with its ecosystem. To bridge the knowledge gap, this paper presents the first comprehensive empirical study of blockchain‐based DApps to date, based on an extensive dataset of 995 Ethereum DApps and 29,846,075 transaction logs over them. We make a descriptive analysis of the popularity of DApps, summarize the patterns of how DApps use smart contracts to access the underlying blockchain, and explore the worth‐addressing issues of deploying and operating DApps. Based on the findings, we propose some implications for DApp users to select proper DApps, for DApp developers to improve the efficiency of DApps, and for blockchain vendors to enhance the support of DApps.
Many real systems can be described by a set of interacting entities forming a complex network. To some surprise, these have been shown to share a number of structural properties regardless of their type or origin. It is thus of vital importance to design simple and intuitive models that can explain their intrinsic structure and dynamics. These can, for instance, be used to study networks analytically or to construct networks not observed in real life. Most models proposed in the literature are of two types. A model can be either static, where edges are added between a fixed set of nodes according to some predefined rule, or evolving, where the number of nodes or edges increases over time. However, some real networks do not grow but rather shrink, meaning that the number of nodes or edges decreases over time. We here propose a simple model of shrinking networks called the war pact model. We show that networks generated in such a way exhibit common structural properties of real networks. Furthermore, compared to classical models, these resemble international trade, correlates of war, Bitcoin transactions and other networks more closely. Network shrinking may therefore represent a reasonable explanation of the evolution of some networks and greater emphasis should be put on such models in the future.
Banks and financial institutions have been spending significant sums to explore potential applications of blockchain technology. The financial services industry is among those areas predicted to benefit the most from blockchain use in the years to come. This chapter investigates this prediction after providing a primer on blockchain. It analyses the potential of blockchain to increase efficiencies and to transform business processes in a number of areas within the industry such as the trade life-cycle of securities and of derivatives, payments, traditional financing arrangements, asset management, insurance and corporate governance. It also examines new currencies and cryptoassets, phenomena ultimately enabled by the use of blockchain technology.
Both the functionality and the flexibility of distributed ledger technology (DLT) systems can raise complex questions of applicable law for users. This chapter considers the challenges of establishing what laws or regulations may be relevant to the operation and governance of DLT systems and transactions conducted on them. It highlights the risks of failing to include express contractual clauses to make the parties' choice of law and forum for dispute resolution clear. It also discusses how governing law and jurisdiction will be assessed in the absence of any express contractual clauses, including an explanation of common DLT governance systems.
Do-hun Kim, Dong-Hwan Kim, Dong‐Ho Lee, Sunjoo Park · 5 authors
With the institutionalization of reducing emissions from deforestation and forest degradation, and the role of conservation, sustainable management of forests, and enhancement of forest carbon stocks in developing countries (REDD+), the global REDD+ financial network has been formed to support the implementation of REDD+ in developing countries. Although the rapid expansion of the network made it decentralized, it is still a highly centralized network in terms of the distribution of financial resources, revolving around only a few major actors. While the source of financing was diversified due to an increase in influential donors, the majority of financing still came from a few constant major donors, and a few constant major developing countries received most of the financial support. Although increases in donor numbers and the amount of finance received can provide more chances to support developing countries, it may cause inefficiency due to overlaps and duplications. Also, over-centralization of financial resources can be ineffective in terms of achieving maximum greenhouse gas (GHG) reduction, and can broaden gaps between developing countries’ ability to cope with climate change and deforestation. Lack of coordination among donors and the differing capacity of developing countries may have caused centralization of financial resources in the global REDD+ financial network. To minimize this problem, a comprehensive monitoring system and platforms for information sharing are needed.
Open access
Conservation, Biodiversity, and Resource Management
Today’s economy is being transformed by digitisation, prompting central banks to seriously consider the issuance of central bank digital currencies (CBDCs’. In that context, many central banks are examining the relevant economic and political factors, as well as necessary regulatory reforms in order to weigh the benefits and disadvantages of issuing CBDCs. In addition to these factors, legal issues related to CBDCs and the possible need to adopt new legislation to address them, also deserve consideration. This chapter examines the legal characteristics of CBDCs by reference to the features of sovereign currencies and cryptocurrencies. It concludes that the issuance of CBDCs will require adapting national legal and regulatory frameworks, in order to ensure clarity around the status and legal characteristics of CBDCs.
Dirk Andreas Zetzsche, Ross P. Buckley, Douglas W. Arner, Anton N. Didenko
The transformative potential of distributed ledger technology (DLT) is attracting significant interest around the world. Many institutions are investing heavily in proof of concept demonstrations, pilot initiatives and the rollout of applications of DLT. Part of the attraction of distributed ledger systems, such as blockchain, lies in their perceived ability to transcend law and regulation. Yet, while the law may be dull and the technology exciting, the impact of the law cannot be simply wished away. With data distributed among many ledgers, legal risks will remain. Legal relationships recorded on, or evidenced by, distributed ledgers may give rise to various forms of liability based on contract, tort, partnership or joint venture structures, specific legislation or breach of fiduciary duties. At the same time, despite existing similarities among common law and civil law systems, the sources of DLT-linked liability may vary substantially across jurisdictions.
Este artigo apresenta uma análise preliminar do mecanismo de consenso para blockchains baseado em Proof-of-Stake com Tempo Discreto (PoSTD). O texto explica os mecanismos que controlam a criação de novos blocos e a eliminação de forks na cadeia. Em seguida, o mecanismo de consenso é analisado de forma genérica, através de diferentes cenários na visão de um determinado nó. É mostrado como o algoritmo atinge o consenso mesmo com atrasos na rede, desde que o tempo de duração de uma rodada de trabalho seja superior ao maior dos atrasos de comunicação entre dois nós quaisquer conectados no sistema.
Recently, technology startups have leveraged the potential of blockchain-based technologies to govern institutions or interpersonal trust by enforcing signed treaties among different individuals in a decentralized environment. However, it is going to be hard enough convincing that the blockchain technology could completely replace the trust among trading partners in the sharing economy as sharing services always operate in a highly dynamic environment. With the rapid expanding of the rental market, the sharing economy faces more and more severe challenges in the form of regulatory uncertainty and concerns about abuses. This paper proposes an enhanced decentralized sharing economy service using the service level agreement (SLA), which documents the services the provider will furnish and defines the service standards the provider is obligated to meet. The SLA specifications are defined as the smart contract, which facilitates multi-user collaboration and automates the process with no involvement of the third party. To demonstrate the usability of the proposed solution in the sharing economy, a notebook sharing case study is implemented using the Hyperledger Fabric. The functionalities of the smart contract are tested using the Hyperledger Composer. Moreover, the efficiency of the designed approach is demonstrated through a series of experimental tests using different performance metrics.
Kien Nguyen, Gabriel Ghinita, Muhammad Naveed, Cyrus Shahabi
Mobile devices with rich features can record videos, traffic parameters or air quality readings along user trajectories. Although such data may be valuable, users are seldom rewarded for collecting them. Emerging digital marketplaces allow owners to advertise their data to interested buyers. We focus on geo-marketplaces, where buyers search data based on geo-tags. Such marketplaces present significant challenges. First, if owners upload data with revealed geo-tags, they expose themselves to serious privacy risks. Second, owners must be accountable for advertised data, and must not be allowed to subsequently alter geo-tags. Third, such a system may be vulnerable to intensive spam activities, where dishonest owners flood the system with fake advertisements. We propose a geo-marketplace that addresses all these concerns. We employ searchable encryption, digital commitments, and blockchain to protect the location privacy of owners while at the same time incorporating accountability and spam-resilience mechanisms. We implement a prototype with two alternative designs that obtain distinct trade-offs between trust assumptions and performance. Our experiments on real location data show that one can achieve the above design goals with practical performance and reasonable financial overhead.
Network coding has emerged as a promising solution to the highly efficient and reliable network requirements for the next generation communication technology. Network coding enabled small cell environment can assure an efficient device to device communication with the high data rate. However, the security challenges inherent to network coding, like pollution attacks, drags a layer of concern over its implementation. Further, the re-encoding of packets at the intermediate nodes makes it difficult to secure network coding enabled communication using standard cryptographic techniques. Homomorphic message authentication codes and signatures are used to tackle this problem. We propose a network coding enabled small cell environment enhanced by blockchain to prevent pollution attacks. The architecture of this blockchain enhanced SECRET small cell along with an analysis of the communication overhead and latency issues are discussed in this paper.
George Suciu, Mari-Anais Sachian, Marius Dobrea, Cristiana-Ioana Istrate · 7 authors
This paper presents how a Smart Grid system is secured and how blockchain implementation provides confidentiality and integrity for such a system. One main issue that has to be addressed in smart grid systems is databases security. Blockchain has been proven to be a safe alternative to be used in mining systems because it allows a secure applicability in databases. Another important feature is that each hash in a crypto mining system cannot be changed if it has such an algorithm behind its build, thus resulting in a secure and reliable system. This paper aims to show how blockchain can affect and be used in a smart power management system going forth from the SealedGRID platform. This system enables the user to monitor in real time the power usage in a smart grid system, therefore, this platform being built with security and resilience against attacks in mind.
Motivated by numerous drivers, blockchain-based peer-to-peer energy trade whitepapers surged in the past two years. Assuming disruption through blockchain technology, they envisioned a transformation of energy systems through technosocio-economic solutions. Few impartial and sober assessments of blockchain-based energy projects exist, and many publications praise disruptive potential without further examination. A more distant and critical perspective, however, is imperative for a responsible use of a novel, in particular disruptive, technology. This review aims at surveying the energy system envisioned by the projects through discussing the projects by their characteristics, their perspective on the transactive energy lifecycle and the energy ecosystem envisioned in the white papers. This review is descriptive and comparative in nature, and attempts to synthesize topics raised in the white papers through methods of grounded theory, as well as assessing the disruptive potential of blockchain technology in energy systems. Through this and a critical and neutral perspective, it strives to (soberly) contribute to a discussion on the digitization of elements of the energy system, and how blockchain-based use cases can contribute constructively to the problems at hand.
Blockchains were initially introduced in 2009, and since then, they have evolved into a revolutionary technology that has affected, not only the digital world but also our everyday lives and activities. Blockchain systems and architectures continue to grow at a fast rate, constantly introducing innovative solutions across multiple research topics. However, despite their wide adoption by the research community, the technology is still not mature enough to address the problems of business use cases. Issues like scalability, complexity, cryptocurrencies' market fluctuations etc. prevent the proposed solutions from being widely accepted. Based on this observation this paper introduces an innovative solution to enable Big Data analysis of private information using blockchains. This solution is based on the Hyperledger Fabric blockchain and is able support the strict privacy and security requirements of operational and business environments.