Peer to Peer (P2P) energy trading were introduced to store, manage, share, track, and access the permanently stored energy data. In particular traditional energy trading systems provide a centralized approach and connectivity among the different participating trusted users. Recently Blockchain Technology shows a potential solution to address critical challenges such as gapped communications, security in an untrusted decentralized environment, inefficient transactions retrieval (low throughput, high latency, high CPU and memory utilization, etc.), and scattered energy records. In this paper a framework is proposed, to record the energy transactions, a JavaScript-based smart contract is deployed over the Hyperledger Sawtooth Proof of Elapsed Time (PoET). Additionally, the proposed framework is shown as a working prototype, and the performances are evaluated taking transaction per second, read and write latency, read write throughput, the number of successful and failed transactions, CPU utilization, network traffic input, and output. Also, it is shown that PoET's performance is better than PoW for multi-hosting environments. It has been observed that out of 1000 transactions sent for each round by clients through Hyperledger Caliper and REST API services, PoET could able to perform 946 transactions successfully, whereas PoW completed only 627 transactions. The results obtained in various rounds of evaluation affirm the superiority of the framework.
Mihai Christodorescu, Erin English, Wanyun Catherine Gu, David Kreissman · 10 authors
With the innovation of distributed ledger technology (DLT), often known as\nblockchain technology, there has been significant growth of digital tokens in\nthe form of cryptocurrencies, stablecoins, and central bank digital currencies.\nAs the number of DLT networks increases, each with varying design\ncharacteristics, the likelihood that transacting parties are on the same\nnetwork decreases. Thus, it is crucial to facilitate payments that are\nuniversal across networks, scalable to massive loads, and highly available. We\nenvision a future payment network that may be built on top of DLT networks\nwithout being subject to their limitations on interoperability, scalability,\nand availability faced by DLT payment solutions today. Specifically, we propose\na hub-and-spoke payment route, referred to here as Universal Payment Channels\n(UPC), that can be used to support digital token transfers of funds across\ndifferent networks through payment channels. We further discuss the potential\nuse cases of the UPC technology to support, and not complicate, an already\nrobust digital payment ecosystem. Finally, through the paper, we share some\nfuture directions of the UPC technology.\n
The central bank digital currency (CBDC) is gaining popularity for the last few years in many countries as it will affect the entire ecosystem of the current financial infrastructure. The CBDC utilizes digital tokens to indicate any nation's fiat/stable currency that manages under distributed ledger technology such as blockchain. Compared to existing cryptocurrencies, the CBDC is regulated by the government monetary policies, including the issuance of digital tokens (i.e., digitized central bank money) and circulation of these digital tokens to the commercial banks, then to the public/end-users. This paper proposes a two-layered CBDC architecture after analyzing the recent research and existing CBDC pilot projects. The distribution layer shows wholesale CBDC based on permission blockchain network (PBN) between the central bank and the commercial banks. While, the user layer describes the functioning of retail CBDC, which shows the interaction between the commercial banks and the end-users through the token-based account. We aim to provide the CBDC design architecture and smart-contract functions for PBN.
Decentralized ecosystems are generally still rarely used in various disciplines. Of all the existing fields, decentralization is only applying to solve problems requiring various partners' organizing. Blockchain has unique characteristics and reflects multiple values related to distinctive and prevalent influences is often referred to by the online community as crypto. This study describes Blockchain-mediated decentralization based on a systematic review on decentralization. This review covers the features of decentralization in a variety of disciplines starting with public administration to science. Blockchain as an intermediary referred to in various scientific articles as an opponent of the binary position interpreted, decentralized and centralized. The author proposes a dialectical design and argues that system jurisdiction allotment is a standard located on the scale amongst pure or centralized decentralization and then notes how a Blockchain arrangement can simultaneously have entities that are significantly centralized whereas others are not. Through a systematic review, we offer a design of Blockchain-mediated decentralization comprehension by having the authors document the findings based on their systematic review. Their proposed framework for generating Blockchain-mediated decentralization comprehension recommends a description and then drawing a new direction for future research on humans into distributed ledger technology.
By sharing resources between edge servers and end users, edge-end cooperation is one important way to support various applications in Internet of Things, which have critical resource requirements on computing, storage, or bandwidth. How to price these resources and how to evaluate the service quality of edge servers are two key issues to support trusted resource allocation for blockchain-enabled Internet of Things. In this article, we provide a trusted resource allocation mechanism based on smart contracts, in which a group-buying pricing mechanism (GBPM) and a reputation evaluation mechanism (REM) are proposed to effectively address the problems existing in resources pricing and service quality evaluation of edge servers. In the trusted resource allocation mechanism, end users can choose a purchase mode from four pricing schemes in terms of actual demands on delay and price, and smart contracts can match end users with high-reputation edge servers automatically. Moreover, end users can submit reputation evaluations to smart contracts based on the behaviors of edge servers. Simulation results show the GBPM can provide differentiated prices and optimize the utility of end users accordingly, while the REM is more sensitive to edge servers with irregular behaviors and quickly reduces their reputations so that the success rate of transactions is improved.
Blockchain technology has the potential to turn into the mainstream in many enterprises including finance, personal identity security and real-time operating systems. The usage of public or permissionless blockchains, in which any participant has the option of joining and leaving at any moment, is growing abruptly. However, the decentralization of permissionless blockchains comes with some main costs which one of them is the limitation of scalability: the transaction loads managed by blockchains are remarkably less than those managed by traditional financial systems. Among many proposals to address the scaling issue, one of the most promising solutions is the Payment Channel Network (PCN), which deploys off-chain settlement of transactions with minimal involvement of expensive on-chain blockchain operations. This work explores the existing PCN solutions, their challenges and the suggested improvements on PCNs, especially routing mechanisms.
Advances in mobile computing have paved the way for new types of distributed applications that can be executed solely by mobile devices on Device-to-Device (D2D) ecosystems (e.g., crowdsensing). Sophisticated applications, like cryptocurrencies, need distributed ledgers (DLs) to function. DLs, such as blockchains and directed acyclic graphs (DAGs), employ consensus protocols to add data in the form of blocks. However, such protocols are designed for resourceful devices that are interconnected via the Internet. Moreover, existing DLs are not deployable to D2D ecosystems since their storage needs are continuously increasing. In this work, we introduce and analyze Mneme, a DAG-based DL that can be maintained solely by mobile devices. Mneme utilizes two novel consensus protocols: 1) Proof of Context (PoC) and 2) Proof of Equivalence (PoE). PoC employs users’ context to add data on Mneme. PoE is executed periodically to summarize data and produce equivalent blocks that require less storage. We analyze Mneme’s security and justify the ability of PoC and PoE to guarantee the characteristics of DLs: persistence and liveness. Furthermore, we analyze potential attacks from malicious users and prove that the probability of a successful attack is inversely proportional to the square of the number of mobile users who maintain Mneme.
Lightweight blockchain inherits the advantages of traditional blockchain, while avoiding excessive reliance on computing and storage resources, and has already been applied in IoV system. This paper combines the characteristics of IoV and node distribution, and proposes a lightweight blockchain architecture oriented to vehicles-road-cloud-server(V2R2CS) collaboration based on the existing lightweight blockchain architecture. Cooperating caching and Block Filtered Algorithm are used to allow road side units(RSUs) to cooperatively store and search blocks, which will further reduce the delay of blockchain query in IoV system. Finally, the simulation experiment proves the feasibility of the algorithm and the good real-time requirement.
In this paper we describe LUNES-Blockchain, an agent-based simulator of blockchains that relies on Parallel and Distributed Simulation (PADS) techniques to obtain high scalability. The software is organized as a multi-level simulator that permits to simulate a virtual environment, made of many nodes running the protocol of a specific Distributed Ledger Technology (DLT), such as the Bitcoin or the Ethereum blockchains. This virtual environment is executed on top of a lower-level Peer-to-Peer (P2P) network overlay, which can be structured based on different topologies and with a given number of nodes and edges. Functionalities at different levels of abstraction are managed separately, by different software modules and with different time granularity. This allows for accurate simulations, where (and when) it is needed, and enhances the simulation performance. Using LUNES-Blockchain, it is possible to simulate different types of attacks on the DLT. In this paper, we specifically focus on the P2P layer, considering the selfish mining, the 51% attack and the Sybil attack. For which concerns selfish mining and the 51% attack, our aim is to understand how much the hash-rate (i.e. a general measure of the processing power in the blockchain network) of the attacker can influence the outcome of the misbehaviour. On the other hand, in the filtering denial of service (i.e. Sybil Attack), we investigate which dissemination protocol in the underlying P2P network makes the system more resilient to a varying number of nodes that drop the messages. The results confirm the viability of the simulation-based techniques for the investigation of security aspects of DLTs.
Christos Chrysoulas, A. M. Thomson, Nikolaos Pitropakis, Pavlos Papadopoulos · 10 authors
The continuously advancing digitization has provided answers to the bureaucratic problems faced by eGovernance services. This innovation led them to an era of automation it has broadened the attack surface and made them a popular target for cyber attacks. eGovernance services utilize internet, which is currently a location addressed system where whoever controls the location controls not only the content itself, but the integrity of that content, and the access to that content. We propose GLASS, a decentralised solution which combines the InterPlanetary File System (IPFS) with Distributed Ledger technology and Smart Contracts to secure EGovernance services. We also create a testbed environment where we measure the IPFS performance.
While many researchers adopt a sharding approach to design scaling blockchains, few works have studied the transaction placement problem incurred by sharding protocols. The widely-used hashing placement algorithm renders an overwhelming portion of transactions as cross-shard. In this paper, we analyze the high cost of cross-shard transactions and reveal that most Bitcoin transactions have simple dependencies and can become single-shard under a placement algorithm taking transaction dependencies into account. In addition, we perform a case study of OptChain, which is the state-of-the-art transaction placement algorithm for sharded blockchains, and find a defect of it. A fix is proposed, and our evaluation results demonstrate that the fix helps OptChain improve the system throughput by 4x.
Teng Long, Shan Qu, Qi Li, Huquan Kang · 7 authors
As the supporting architecture of cryptocurrencies, blockchain is also showing its promising potential to be applied to mobile devices. Being WiFi supported, mobile devices nowadays are able to perform ad-hoc local communications in multi-hop manners, thus can potentially extend cryptocurrency service into areas without stable Internet connection. However, traditional blockchain architecture suffers from the intolerably high block propagation latency and communication cost which will be even trickier if adopted in wireless multi-hop networks (WMNs). This paper aims to reduce this latency and cost by leveraging node weights to distinguish the feedback speed of different nodes and constructing a low-length multicast tree to select a subset of nodes with higher feedback speed to participate in the block verification. Thus, block propagation is depicted by the minimum length multicast tree, intrinsically the Steiner Tree Problem. The primary challenge lies in that the WMNs only allow local communication and the distributed consensus protocol of the blockchain makes a predetermination of receiver nodes impossible. We design our algorithm via a ``toward source'' Steiner tree approach in favor of the distributed environment. Tree construction proceeds by progressively enlarging the searching areas until the accumulated weight of receiver nodes reaches a threshold. Our algorithm provably returns a tree length fairly close to that of the optimal Steiner tree with latency$O(\sqrt{n\log n})$(where$n$represents the number of nodes in the network), the best so far. Furthermore, our algorithm is empirically validated to provide instructive insights for efficient block propagation with applications in Bitcoin network.
Purpose This paper aims to help information professionals understand the foundational concepts of this technology and how these are related to libraries so that they can evolve services alongside it. Design/methodology/approach This column will define what a non-fungible tokens (NFT) is, explore the relevant trends impacting its development and examine how it intersects with the traditional roles of the library. Findings NFTs represent a new and growing technology that intersections with many of the same concepts that are core to librarianship. Libraries are community institutions that engender widespread trust, whereas NFTs are built atop cryptocurrency that seeks to enable anonymous peer-to-peer interactions. Originality/value Summary.
Phillipe Austria, Chol Hyun Park, Alex Hoffman, Yoohwan Kim
Cloud storage has become a prevalent choice for data storage for both business and personal use due to increasing data use. While cloud storage services, such as Google Drive, provide customers with high levels of data integrity and security, customers however lose privacy and require trust in the service provider to not act maliciously with their data. We explore an alternative to centralized, traditional cloud storage (TCS) using blockchain technology. In this paper, we tested and evaluated the performance and cost of Sia, a decentralized blockchain-based storage platform (BBS) that ensures users' privacy. The platform allows users to rent storage space from other users in exchange for Siacoin, Sia's native currency. Metrics were evaluated through various storage tests and results were compared to Google Drive. Performance tests showed Sia's available time, how long it takes for a file to upload and be download ready, to be 8–12 times slower than Google Drive. In contrast, Sia downloads were 2–3 times faster. Cost test revealed Sia's overall storage spending to be comparable to Google Drive and other popular TCS; however, results raised questions about spending details. Further testing is needed to fully understand the complexities of a BBS platform like Sia.
Peer-to-peer (P2P) electricity trading promotes the local consumption of renewable energy. However, it suffers from high transaction costs and mutual distrust among users. To address these issues, we propose a credit-based P2P electricity trading model in a blockchain environment. First, the P2P electricity trading process is introduced, which involves six stages: order generation, default query, order picking, trading execution, trading verification, and payment. Credit management is also introduced in this model to manage the default behavior of users. In particular, the default users are provided a waiting time in the default query stage or penalized in the payment stage. Finally, the model is simulated on the Hyperledger Fabric platform using Docker and Go. Experimental results show that the proposed model can facilitate cost reduction for users in the blockchain and realize credit management in P2P electricity trading, thereby enhancing trading stability and efficiency.
Virtual reality (VR) streaming is becoming a popular mobile application that requires ultralow latency and active participation of devices. Meanwhile, blockchain is a promising paradigm to decentralize the traditional ledger of a single trusted entity. In this article, a deep deterministic policy gradient (DDPG)-based scheme is proposed to tackle the joint resource allocation and replica selection challenge of VR streaming in blockchain-enabled fog radio access networks (F-RANs). The proposed scheme balances the load on VR streaming and blockchain maintenance and fully exploits the edge caching and computing resources on fog-based access points (F-APs). Thus, less energy is consumed compared with other learning schemes based on extensive simulations.
Aeri Kim, Jungyeon Kim, Meryam Essaid, Sejin Park · 5 authors
Bitcoin is a blockchain-based network where thousands of nodes are directly connected and communicate through a gossip-based flooding protocol. Mined blocks are propagated to all participating nodes in the network through compact block relay (CBR) protocol. Therefore, reducing the block relay time between nodes can reduce the block propagation time to all nodes and ultimately improve the performance of Bitcoin. In order to reduce the block relay time, the delivery time between nodes must be measured and analyzed to find the cause of the delay and provide ways to resolve it. Therefore, in this paper, we measure the CBR time between directly connected Bitcoin nodes and analyze the cause of the relay delay. Our results show that the delivery time delay is affected by whether or not a transaction is requested when assembling the compact block. In addition, the reason for requesting a transaction is due to the transaction propagation method and the characteristics of the transaction itself.
Soo Hoon Maeng, Meryam Essaid, Sejin Park, Hongtaek Ju
The Ethereum network uses Kademlia, a well-known P2P network, which allows the search for new nodes, and the change of connection with neighboring nodes. The Ethereum network must cope with security attacks such as DDoS attacks, 51% attacks, and Sybil attacks, and scalability issues, which slows down the transaction processing speed per second (TPS) as the network expands. A deep analysis of the dynamically changing topology and the connection between the nodes constituting the topology is needed to solve these problems. Therefore, in this paper, we measure the topology in the Ethereum network using a passive probing data collection to search for active nodes in the network and an active probing method to check the activity of nodes participating in the Ethereum network. Our results give a clear insight into the topology properties and topology visualization.
Since Bitcoin was launched, the blockchain technology and the cryptocurrencies have been in the spotlight. Ethereum, the second-generation blockchain introduced smart contracts, and many DApps have emerged due to them. Those DApps showed the feasibility of blockchain in various industries. However, even though the growth of blockchain technology, still many DApps are based on Ethereum, and supper its performance issue. Since the performance evaluation in Ethereum mainnet is almost impossible, and there are no formalized performance evaluation frameworks, it is hard to perform appropriate performance evaluation of Ethereum. Detail performance evaluations on Ethereum networks are essential for developing and operating DApps. In this paper, we use Hyperledger Caliper, an automated performance evaluation framework to evaluate an Ethereum private network, and the Ropsten testnet to overcome above problems. We evaluate the performance with a specific smart contract and analyze the results. Our evaluation results show that the Ethereum private network performs better than the Ropsten testnet, and the Ropsten testnet is unstable for performance evaluation. In addition, our results show that the performance of the transactions can differ following their content.
In recent years, research has shown the networking layer’s significant influence on the scalability, security, and privacy of blockchain systems. Such large-scale networks however exhibit a degree of complexity that demands model-based simulations as real-world experiments are often not possible. In this work, we methodically characterize blockchain networks by reference to the paradigmatic Bitcoin peer-to-peer network, explore the state-of-the-art protocols, and emphasize this key design space. To this end, we conducted a longitudinal measurement study on the Bitcoin network, from which we extract a comprehensive network model and implement it as part of the bns network simulation framework. We validate the model in comparison to real-world measurements as well as to results from related work. Moreover, we experimentally show how network utilization and miners’ geographical location impact the block propagation characteristics.