With the growing maturity of blockchain technology, its peer-to-peer model and fully duplicated data storage pattern enable blockchain to act as a distributed ledger in untrustworthy environments. Blockchain storage has also become a research hotspot in industry, finance, and academia due to its security, and its unique data storage management model is gradually becoming a key technology to play its value in various fieldsâ applications. However, with the increasing amount of data written into the blockchain, the blockchain system faces many problems in its actual implementation of the application, such as high storage space occupation, low data flexibility and availability, low retrieval efficiency, poor scalability, etc. To improve the above problems, this paper combines off-chain storage technology and de-duplication technology to optimize the blockchain storage model. Firstly, this paper adopts the double-chain model to reduce the data storage of the major chain system, which stores a small amount of primary data and supervises the vice chain through an Application Programming Interface (API). The vice chain stores a large number of copies of data as well as non-transactional data. Our model divides the vice chain storage system into two layers, including a storage layer and a processing layer. In the processing layer, deduplication technology is applied to reduce the redundancy of vice chain data. Our double-chain storage model with high scalability enhances data flexibility, is more suitable as a distributed storage system, and performs well in data retrieval.
Yustus Eko Oktian, Thi-Thu-Huong Le, Uk Jo, Howon Kim
Bandwidth trading procedures can be made to incentivize users to sell their needless traffic and indirectly reduce the probability of traffic congestion. However, implementation of bandwidth trading is opex-heavy from Internet Service Provider (ISP) perspective, while on the other hand, users also do not trust network executions from the ISP due to its heavily centralized control. These issues hinder the applicability of bandwidth trading and become our motivation to propose this paper. Our bandwidth-trading framework utilize software-defined networking (SDN) and blockchain. SDN automates the bandwidth trading executions from the ISP side and reduces the opex. Meanwhile, the smart contract is a trusted platform for building a trading marketplace where buyers, sellers, and SDN controllers can negotiate the trading terms. Once the trading is executed, SDN controllers generate proof of trading that must be submitted to the smart contract as proof of provisioning. We implement our works using Ethereum and POX SDN controllers, and the results prove that it can provide a seamless bandwidth trading experience with reasonable overhead. Furthermore, by committing to our framework, bandwidth trading can be executed fairly and securely because all previous provisioning can be cross-checked through the provided proof-of-trading.
The rapid advancement in the area of the Internet of Vehicles (IoV) has provided numerous\ncomforts to users due to its capability to support vehicles with wireless data communication. The\nexchange of information among vehicle nodes is critical due to the rapid and changing topologies,\nhigh mobility of nodes, and unpredictable network conditions. Finding a single trusted entity to\nstore and distribute messages among vehicle nodes is also a challenging task. IoV is exposed to\nvarious security and privacy threats such as hijacking and unauthorized location tracking of smart\nvehicles. Traceability is an increasingly important aspect of vehicular communication to detect and\npenalize malicious nodes. Moreover, achieving both privacy and traceability can also be a challenging\ntask. To address these challenges, this paper presents a blockchain-based efficient, secure, and\nanonymous conditional privacy-preserving and authentication mechanism for IoV networks. This\nsolution is based on blockchain to allow vehicle nodes with mechanisms to become anonymous and\ntake control of their data during the data communication and voting process. The proposed secure\nscheme provides conditional privacy to the users and the vehicles. To ensure anonymity, traceability,\nand unlinkability of data sharing among vehicles, we utilize Hyperledger Fabric to establish the\nblockchain. The proposed scheme fulfills the requirement to analyze different algorithms and\nschemes which are adopted for blockchain technology for a decentralized, secure, efficient, private,\nand traceable system. The proposed scheme examines and evaluates different consensus algorithms\nused in the blockchain and anonymization techniques to preserve privacy. This study also proposes\na reputation-based voting system for Hyperledger Fabric to ensure a secure and reliable leader\nselection process in its consensus algorithm. The proposed scheme is evaluated with the existing\nstate-of-the-art schemes and achieves better results.
In the last era the number of internet-connected devices surpassed the human population. IoT integration rate into human world equals at least five times the rate of electricity and telephony. Currently in 2020 the number of IoT devices is around 50 billion smart objects. This great invasion to our live requires extensive efforts for controlling and securing those devices. BlockChain (BC) is a distributed write-only ledger that eliminates the need for third party in securing and verifying transactions between peers. BC is considered the most powerful technique for securing transactions between IoT devices. In this work, a robust and scalable blockchain-based security framework for IoT is proposed. This framework comprises clients, device gateways, and administrators. IoT devices access BC through gateways. Ethereum BlockChain is utilized in addition to Ethereum smart contracts for enforcing a set of rules defined by the system administrator. Finally metrics that fulfill both efficiency and effectiveness of the proposed framework are introduced. In the results section, the proposed work provides robust and scalable security framework for the IoT devices under different attack probabilities in addition to satisfying the conditions of lightweight, transparency, and timeliness.
As a decentralized database technology, blockchain is increasingly being applied to smart grids. This paper proposes a blockchain-based smart microgrid power transaction model. The model realizes the power dispatching between users and agents in the microgrid through two-way auctions and point-to-point transactions and optimizes energy allocation through market regulation. And based on the Ethereum private chain, it ensures the openness, transparency, safety, and reliability of transactions. The simulation results show that the open and reliable features of the blockchain improve the efficiency of power dispatching, and verify the feasibility and effectiveness of the model.
Muhammad Imran, Bin Yao, Waqas Ali, Adnan Akhunzada · 7 authors
Blockchain technology in recent years has become potentially pervasive in the cryptocurrency market, thus providing tamper-proof security to decentralized transaction management systems. Structurally, the design foundation is an ideal advancement of the distributed ledger technology that maintains a set of global states across nodes. As technology expands with a higher trend towards mobile computing, the development of new applications demands understanding the current progression, especially concerning performance, data management, and storage prospects. Here, we report the principle design structure of the blockchain technology combined with the state of the arts, thus characterizing their original topological contexts. We depart from the fundamental concepts of the technology and analyze performance of the Ethereum blockchain on two devices having different computing power. Our presentation is tailored to provide a systematic review of the technology, thus facilitating their possible adoption into the new application domains like the Internet of Things (IoT). Further, we developed Debug-Bench, the first VSCode (Visual Studio Code) extension that enables benchmarking and profiling of the blockchain applications. Finally, we demonstrate several critical challenges concerning the design space of the current blockchain platforms for their implementation over resource-constrained devices.
The Internet of Things (IoT) has become an essential part of our society. IoT devices are used in our houses, hospitals, cars, industry, etc., making our lives easier. Nonetheless, there are a number of serious concerns about security, privacy and performance issues in IoT. It has been proven that the aforementioned issues are strictly related to the high degree of centralisation of current IoT architecture. Thus, there is an increasing interest in adopting blockchain in IoT. However, blockchain adoption is not straightforward due to the power, storage and computational limitations of IoT. Consequently, the concept of lightweight blockchain is getting more and more attention from researchers and engineers. In this paper, we conduct a systematic literature review on the lightweight blockchain concept for IoT following the PRISMA methodology. We systematically analyse âlightweight blockchain for IoTâ proposals in order to better understand the limitations of blockchain for IoT, the characteristics of the current work on this topic and further research opportunities. Specifically, we analyse the definition of lightweight blockchain that other authors give, the characteristics of the reviewed proposals, their âlightweightâ aspects and their evaluation. Finally, we discuss the results of the review along with further research opportunities. Consequently, this work is mostly focused on understanding the technical and performance-related aspects of blockchain for IoT as a prelude to more specific analysis such as security (i.e., attacks, vulnerabilities, etc.).
Carlos NĂșñezâGĂłmez, Carmen CarriĂłn, Blanca Caminero, Francisco M. Delicado
Fog computing arises as a complement to cloud computing where computing and storage are provided in a decentralized way rather than the centralized approach of the cloud paradigm. In addition, blockchain provides a decentralized and immutable ledger which can provide support for running arbitrary logic thanks to smart contracts. These facts can lead to harness smart contracts on blockchain as the basis for a decentralized, autonomous, and resilient orchestrator for the resources in the fog. However, the potentially vast amount of geographically distributed fog nodes may threaten the feasibility of the orchestration. On the other hand, fog nodes can exhibit highly dynamic workloads which may result in the orchestrator redistributing the services among them. Thus, there is also a need to dynamically support the network connections to those services independently of their location. Software Defined Networking (SDN) can be integrated within the orchestrator to carry out a seamless service management. To tackle both aforementioned issues, the S-HIDRA architecture is proposed. It integrates SDN support within a blockchain-based orchestrator of container-based services for fog environments, in order to provide low network latency and high service availability. Also, a domain-based architecture is outlined \marev{as potential scenario} to address the geographic distributed nature of fog environments. Results obtained from a proof-of-concept implementation assess the required functionality for S-HIDRA.
Blockchain is a promising technology that has received extensive attention from academia and industry in various subject domains. The significant potential of blockchain technology lies in its key characteristics of decentralization, persistency, anonymity, and auditability. However, the development of blockchain applications faces many technical difficulties because such applications are highly complex and heterogeneous, involving cooperation and interoperation between legacy systems and blockchain systems. These difficulties are further exacerbated by the lack of a common understanding of different blockchain solutions and components from a software engineering perspective. This study proposes a taxonomy to classify the eight fundamental components of blockchain systems. These components comprise a platform, network, distributed ledger, smart contract, consensus protocol, digital wallet, token, and node. Under the proposed taxonomy, each component is divided into several aspects (i.e., characteristics) that collectively describe the component. As a result of this elaboration, the taxonomy organizes the eight components into 83 dimensions and 199 characteristics. The taxonomy was validated using illustrative scenarios and a case study. The proposed taxonomy aims to provide a better understanding of the interrelationships among different blockchain components and aspects. Such an understanding can help blockchain application developers to design better blockchain architectures and systems.
Decentralization is essential when trust and performance must not depend on a single organization. Distributed Ledger Technologies (DLTs) and Decentralized Hash Tables (DHTs) are examples where the DLT is useful for transactional events, and the DHT is useful for large-scale data storage. The combination of these two technologies can meet many challenges. The blockchain is a DLT with immutable history protected by cryptographic signatures in data blocks. Identification is an essential issue traditionally provided by centralized trust anchors. Self-sovereign identities (SSIs) are proposed decentralized models where users can control and manage their identities with the help of DHT. However, slowness is a challenge among decentralized identification systems because of many connections and requests among participants. In this article, we focus on decentralized identification by DLT and DHT, where users can control their information and store biometrics. We survey some existing alternatives and address the performance challenge by comparing different decentralized identification technologies based on execution time and throughput. We show that the DHT and machine learning model (BioIPFS) performs better than other solutions such as uPort, ShoCard, and BBID.
Henri T. Heinonen, Alexander Semenov, Jari Veijalainen, Timo HÀmÀlÀinen
According to recent estimates, one bitcoin transaction consumes as much energy as 1.5 million Visa transactions. Why is bitcoin using so much energy? Most of the energy is used during the bitcoin mining process, which serves at least two significant purposes: a) distributing new cryptocurrency coins to the cryptoeconomy and b) securing the Bitcoin blockchain ledger. In reality, the comparison of bitcoin transactions to Visa transactions is not that simple. The amount of transactions in the Bitcoin network is not directly connected to the amount of bitcoin mining power nor the energy consumption of those mining devices; for example, it is possible to multiply the number of bitcoin transactions per second without increasing the mining power and the energy consumption. Bitcoin is not only “digital money for hackers”. It has very promising future potential as a global reserve currency and a method to make the World Wide Web (WWW) immune to cyberattacks such as the Distributed Denial-of-Service attacks. This survey approached cryptocurrencies’ various technological and environmental issues from many different perspectives. To make various cryptocurrencies, including bitcoin (BTC) and ether (ETH), greener and more justified, what technological solutions do we have? We found that cryptocurrency mining might be cleaner than is generally expected. There is also a plan to make a vast renewable energy source available by combining Ocean Thermal Energy Conversion and Bitcoin mining. There are plans to use unconventional computing methods (quantum computing, reversible computing, ternary computing, optical computing, analog computing) to solve some of the issues regarding the vast energy consumption of conventional computing (including cryptocurrency mining). We think using spare computing cycles for grid computing efforts is justified. For example, there are billions of smartphones in the world. Many smartphones are being recharged every day. If this daily recharging period of twenty to sixty minutes would be used for grid computing, for example, finding new cures to cancer, it would probably be a significant breakthrough for medical research simulations. We call cryptocurrency communities to research and develop grid computing and unconventional computing methods for the most significant cryptocurrencies: bitcoin (BTC) and ether (ETH).
Aspiring to achieve an accurate Bitcoin price prediction based on people's opinions on Twitter usually requires millions of tweets, using different text mining techniques (preprocessing, tokenization, stemming, stop word removal), and developing a machine learning model to perform the prediction. These attempts lead to the employment of a significant amount of computer power, central processing unit (CPU) utilization, random-access memory (RAM) usage, and time. To address this issue, in this paper, we consider a classification of tweet attributes that effects on price changes and computer resource usage levels while obtaining an accurate price prediction. To classify tweet attributes having a high effect on price movement, we collect all Bitcoin-related tweets posted in a certain period and divide them into four categories based on the following tweet attributes: $(i)$ the number of followers of the tweet poster, $(ii)$ the number of comments on the tweet, $(iii)$ the number of likes, and $(iv)$ the number of retweets. We separately train and test by using the Q-learning model with the above four categorized sets of tweets and find the best accurate prediction among them. Especially, we design several reward functions to improve the prediction accuracy of the Q-leaning. We compare our approach with a classic approach where all Bitcoin-related tweets are used as input data for the model, by analyzing the CPU workloads, RAM usage, memory, time, and prediction accuracy. The results show that tweets posted by users with the most followers have the most influence on a future price, and their utilization leads to spending 80\% less time, 88.8\% less CPU consumption, and 12.5\% more accurate predictions compared with the classic approach.
Ahto Buldas, Dirk Draheim, Mike Gault, Risto Laanoja · 11 authors
<p>Since its introduction with Bitcoin in 2009, blockchain technology has received tremendous attention by academia, industry, politics and media alike, in particular, through extended blockchain-based visions such as smart contracts, decentralized finance, and, most recently, Web3. The critical prerequisite for any such blockchain-based vision to be turned into reality is uncapped scalability. Furthermore, and equally important, blockchain technology needs to transcend the stage of specialized tokens into an adaptive, heterogeneous tokenization platform. In this paper, we explain the Alphabill family of technologies that addresses both unlimited scalability and unrestricted adaptivity. We deliver a sharded blockchain technology with unlimited scalability and performance, called KSI Cash, which is based on a new form of electronic money scheme, the bill scheme. We present performance tests of KSI Cash that we have conducted with the European Central Bank and a group of eight national central banks from the Eurosystem in order to assess the technological feasibility of a digital euro, showing the system operating with 100 million wallets and 15 thousand transactions per second (under simulation of realistic usage), having an estimated carbon footprint of 0.0001g CO2 per transaction (Bitcoin = 100 kg and more); furthermore, showing the system operating with up to 2 million payment orders per second, an equivalent of more than 300.000 transactions per second (in a laboratory setting with the central components of KSI Cash), scaling linearly in terms of the number of deployed shards. We explain, in detail, the key concepts that unlock this performance (i.e., the concepts of the bill money scheme). The results provide evidence that the scalability of our technology is unlimited in both permissioned and permissionless scenarios, resulting into the Alphabill Money technology. Next, we contribute the architecture of a universal tokenization platform that allows for universal asset tokenization, transfer and exchange as a global medium of exchange, called Alphabill platform. We reveal the crucial conceptual and technical contributions of the platform's architecture and their interplay, including the data structures of KSI Cash and Alphabill Money, the dust collection solution of Alphabill Money, and the atomic swap solution of the Alphabill platform.</p>
Quinten Stokkink, Can Umut Ileri, Dick Epema, Johan Pouwelse
Web3 is emerging as the new Internet-interaction model that facilitates direct collaboration between strangers without a need for prior trust between network participants and without central authorities. However, one of its shortcomings is the lack of a defense mechanism against the ability of a single user to generate a surplus of identities, known as the Sybil attack. Web3 has a Sybil attack problem because it uses peer sampling to establish connections between users. We evaluate the promising but underexplored direction of Sybil avoidance using network latency measurements, according to which two identities with equal latencies are suspected to be operated from the same node, and thus are likely Sybils. Network latency measurements have two desirable properties: they are only malleable by attackers by adding latency, and they do not require any trust between network participants. Our basic SybilSys mechanism avoids Sybil attackers using only network latency measurements if attackers do not actively exploit their malleability. We present an enhanced version of SybilSys that protects against targeted attacks using a variant of the flow correlation attack, which we name TrafficJamTrigger. We show how the message flows of Round-Trip Time measurements can be used to expose attack patterns and we propose and evaluate six classifiers to recognize these patterns. Our experiments show, through both emulation and real-world deployment, that enhanced SybilSys can serve a fundamental role for Web3, effectively establishing connections to real users even in the face of networks consisting of 99% Sybils.
Ahto Buldas, Dirk Draheim, Mike Gault, MĂ€rt Saarepera
Abstract The Web3 vision takes blockchain disintermediation to a next level by making it ubiquitous, encompassing not only payments and financial services but also digital identities, data and business models. Recently, Web3 has gained massive attention by major analysts such as Gartner, Forrester, Forbes Technology Council and the Harvard Business Review. Albeit the current enthusiasm about Web3, we are lost in a state of confusion about what Web3 actually is â or could be. In this paper, we take an engineering approach. We discuss a potential foundation of Web3 in terms of fundamental components, architectural principles and a Web3 design space. We conclude that, from an engineering viewpoint, the Web3 can be characterized as the integration of digital rights exchange into the (application layer) internet protocols. Finally, on the basis of these findings, we discuss the Alphabill platform as a Web3 enabling technology.
Louis Tremblay Thibault, Tom Sarry, Abdelhakim Hafid
Blockchain systems have seen much growth in recent years due to the immense potential attributed to the technology behind these systems. However, this popularity has outlined a critical scalability issue that most blockchain systems are now confronted with. With their increasing popularity comes an increasing amount of load on the system. Several scaling solutions that modify either the functioning of the underlying protocol or that build on top of them have already been proposed; however, each of these solutions comes with their advantages and disadvantages. This paper aims to survey the current state-of-the-art of rollups as a scaling solution. We discuss the mode of operation of the different types of rollups, outline state-of-the-art implementations of each type together with their features and limitations. We also conduct a performance analysis comparing these implementations. Finally, we outline avenues for future research around rollups as a scaling solution.
Nowadays, sharding is deemed as a promising way to save traditional blockchain protocols from their low scalability. However, such technique also brings several potential risks and huge communication overheads. An improper design may give rise to the inconsistent state among different committees. Further, the communication overheads arising from cross-shard transactions unfortunately reduce the system's performance. In this paper, we first summarize five essential issues that all sharding blockchain designers face. For each issue, we discuss its key challenge and propose our suggested solutions. In order to break the performance bottlenecks, we propose a reputation mechanism for selecting leaders. The term of reputation in our design reflects each node's honest computation resources. In addition, we introduce a referee committee and partial sets in each committee, and design a recovery procedure in case the leader is malicious. Under the design, we prove that malicious leaders will not hurt the system and will be evicted. Furthermore, we conduct a series of simulations to evaluate our design. The results show that selecting leaders by the reputation can dramatically improve the system performance.
Xiaoyang Shi, Hang Xiao, Weifeng Liu, Xi Chen · 7 authors
The distributed consensus mechanism is the backbone of the rapidly developing blockchain network. Blockchain platforms consume vast amounts of electricity based on the current consensus mechanism of Proof-of-Work (PoW). Here, we point out a different consensus mechanism named Proof-of-Stake (PoS) that can eliminate the extensive energy consumption of the current PoW-based blockchain. We comprehensively elucidate the current and projected energy consumption and carbon footprint of the PoW- and PoS-based Bitcoin and Ethereum blockchain platforms. The model of energy consumption of PoS-based Ethereum blockchain can lead the way toward the prediction of other PoS-based blockchain technologies in the future. With the widespread adoption of blockchain technology, if the current PoW mechanism continues to be employed, the carbon footprint of Bitcoin and Ethereum will push the global temperature above 1.5 °C in this century. However, a PoS-based blockchain can reduce the carbon footprint by 99% compared to the PoW mechanism. The small amount of carbon footprint from PoS-based blockchain could make blockchain an attractive technology in a carbon-constrained future. The study sheds light on the urgency of developing the PoS mechanism to solve the current sustainability problem of blockchain.
Fog Radio Access Network (F-RAN) has been regarded as a promising solution to the alleviation of the ever-increasing traffic burden on current and future wireless networks, for it shifts the caching and computing resources from remote cloud to the network edge. However, it makes wireless networks more vulnerable to security attacks as well. To resolve this issue, in this article, we propose a secure yet trustless Blockchain-based F-RAN (BF-RAN), which allows a massive number of trustless devices to form a large-scale trusted cooperative network by leveraging the key features of blockchain, such as decentralization, tamper-proof, and traceability. The architecture of BF-RAN is first presented. Then, the key technologies, including access control, dynamic resource management, and network deployment are discussed. Finally, challenges and open problems in the BF-RAN are identified.
Cong T. Nguyen, Dinh Thai Hoang, Diep N. Nguyen, Eryk Dutkiewicz
Metaverse has recently attracted paramount attention due to its potential for future Internet. However, to fully realize such potential, Metaverse applications have to overcome various challenges such as massive resource demands, interoperability among applications, and security and privacy concerns. In this paper, we propose MetaChain, a novel blockchain-based framework to address emerging challenges for the development of Metaverse applications. In particular, by utilizing the smart contract mechanism, MetaChain can effectively manage and automate complex interactions among the Metaverse Service Provider (MSP) and the Metaverse users (MUs). In addition, to allow the MSP to efficiently allocate its resources for Metaverse applications and MUsâ demands, we design a novel sharding scheme to improve the underlying blockchainâs scalability. Moreover, to leverage MUsâ resources as well as to attract more MUs to support Metaverse operations, we develop an incentive mechanism using the Stackelberg game theory that rewards MUsâ contributions to the Metaverse. Through numerical experiments, we clearly show the impacts of the MUsâ behaviors and how the incentive mechanism can attract more MUs and resources to the Metaverse.
E-Donation cloud funding system is an indispensable part of the society. It is a feasible method to assist any donors in any part of the world. Donors require fully secured system where there all information will not be hacked by hackers. As Web 3.0 is the third generation of internet services that can make the system fully secured which is distributed decentralized and semantic. It means with the Artificial Intelligence (AI); it does not have a centralized control node. Public Blockchain- a decentralized, distributed ledger technology - is the implementation of Web 3.0 that technology will be used to develop this system which would be an open source. This paper will look into Ethereum Blockchain technology and recognize the fundamental support it provides for Web 3.0 framework.
Internet of Things (IoT) is the new paradigm to the scaling nature of things and their elements, interconnected, exchanging data over a network supported with nodes. The Ubiquitous use of tiny devices and embedded sensor frameworks has pushed IoT to the forefront of emerging technologies used in many applications like peer-to-peer networks, smart energy grids, home and building automation, vehicle to vehicle communication, and wearable computing devices. This massive growth and extensive use brought forth security risks that could hinder its commencement in many novel applications. The number of interconnected devices leads the way to several entry points for intruders and, along with it, security risks. The sensitive nature of the IoT applications such as health, automation, and energy grids cannot afford security risks. Traditional security mechanisms will not design or develop to secure such an emerging technology as IoT. Existing technologies have to be relied on with the non-existence of security mechanisms for this purpose. Distributed Ledger Technology (DLT) is one such technology that can reduce the security risks in IoT. The central node vulnerability that can compromise the whole system can be mitigated by eliminating the need for a central node by using the distributed ledger. Blockchain, a distributed ledger technology, has attracted tremendous attention and harnessed in itself a real-world value. However, computationally costly with limited scalability is not entirely suited for the IoT environment. IoT Application (IOTA) technology is the distributed ledger technology that can provide unlimited scalability specifically suitable for the IoT industry. This survey provides an in-depth introduction to how blockchain performs and its constraints in its nature as a generic platform for DLT. In contrast, IOTA is introduced as the technology for IoT, the next-generation blockchain overcoming blockchainâs limitations for its use in IoT.