Peer-to-peer (p2p) content delivery is promising to reduce the cost of traditional CDNs and complement the decentralized storage networks such as Filecoin. However, reliable p2p delivery requires proper enforcement of delivery fairness, i.e., the deliverers should be rewarded according to their in-time delivery. Unfortunately, most existing studies on delivery fairness are based on non-cooperative game-theoretic assumptions that are arguably unrealistic in the ad-hoc p2p setting. We for the first time put forth the expressive yet still minimalist securities for p2p content delivery, and give two efficient solutions FairDownload and FairStream via the blockchain for p2p downloading and p2p streaming scenarios, respectively. Our designs not only guarantee delivery fairness to ensure deliverers be paid (nearly) proportional to his in-time delivery, but also ensure the content consumers and content providers to be fairly treated. The fairness of each party can be guaranteed when the other two parties collude to arbitrarily misbehave. Moreover, the systems are efficient in the sense of attaining asymptotically optimal on-chain costs and optimal deliverer communication. We implement the protocols to build the prototype systems atop the Ethereum Ropsten network. Extensive experiments done in LAN and WAN settings showcase their high practicality.
Lorenzo Ghiro, Francesco Restuccia, Salvatore D’Oro, Stefano Basagni · 7 authors
The use of the term blockchain is documented for disparate projects, from\ncryptocurrencies to applications for the Internet of Things (IoT), and many\nmore. The concept of blockchain appears therefore blurred, as it is hard to\nbelieve that the same technology can empower applications that have extremely\ndifferent requirements and exhibit dissimilar performance and security. This\nposition paper elaborates on the theory of distributed systems to advance a\nclear definition of blockchain that allows us to clarify its role in the IoT.\nThis definition inextricably binds together three elements that, as a whole,\nprovide the blockchain with those unique features that distinguish it from\nother distributed ledger technologies: immutability, transparency and\nanonimity. We note however that immutability comes at the expense of remarkable\nresource consumption, transparency demands no confidentiality and anonymity\nprevents user identification and registration. This is in stark contrast to the\nrequirements of most IoT applications that are made up of resource constrained\ndevices, whose data need to be kept confidential and users to be clearly known.\nBuilding on the proposed definition, we derive new guidelines for selecting the\nproper distributed ledger technology depending on application requirements and\ntrust models, identifying common pitfalls leading to improper applications of\nthe blockchain. We finally indicate a feasible role of the blockchain for the\nIoT: myriads of local, IoT transactions can be aggregated off-chain and then be\nsuccessfully recorded on an external blockchain as a means of public\naccountability when required.\n
Multi-service networks aim to efficiently supply distinct goods within the same infrastructure by relying on a (typically centralised) authority to manage and coordinate their differential delivery at specific prices. In turn, final customers constantly seek to lower costs whilst maximising quality and reliability. This paper proposes a decentralised business model for multi-service networks using Ethereum blockchain features – gas, transactions, and smart contracts – to execute multiple services at different prices. By employing the Ethereum cryptocurrency token, Ether, to quantify the quality of service and reliability of distinct private Ethereum networks, our model concurrently processes streams of services at different gas prices while differentially delivering reliability and service quality. This multi-service business model has been extensively tested on five concurrent Ethereum networks with various combinations of gas prices, miners, and regular nodes using a Proof of Authority consensus algorithm and throughput as the evaluation metric. It has exhibited linear scalability, providing increased throughput in high-quality Ethereum networks, i.e., composed of more validator nodes. The results also indicate that different mining prices do not impact the network performance, but networks with more miners had limited scalability and an increased level of trustworthiness and reliability.
Muneeb Ul Hassan, Mubashir Husain Rehmani, Jinjun Chen
Traditional smart grid energy auctions cannot directly be integrated in blockchain due to its decentralized nature. Therefore, research works are being carried out to propose efficient decentralized auctions for energy trading. Since, blockchain is a novel paradigm which ensures trust, but it also comes up with a curse of high computation and communication complexity which eventually causes resource scarcity. Therefore, there is a need to develop and encourage development of greener and computational-friendly auctions to carry out decentralized energy trading. In this paper, we first provide a thorough motivation of decentralized auctions over traditional auctions. Afterwards, we provide in-depth design requirements that can be taken into consideration while developing such auctions. After that, we analyze technical works that have developed blockchain based energy auctions from green perspective. Finally, we summarize the article by providing challenges and possible future research directions of blockchain based energy auction from green viewpoint.
Muhammad Anas Imtiaz, David Starobinski, Ari Trachtenberg
Orphan transactions are those whose parental income sources are missing at the time that they are processed. These transactions typically languish in a local buffer until they are evicted or all their parents are discovered, at which point they may be propagated further. To date, there has been little work in the literature on characterizing the nature and impact of such orphans, and yet it is intuitive that they should affect the performance of the Bitcoin network. This work thus seeks to methodically research such effects through a measurement campaign on live Bitcoin nodes. Our data show that about 45% of orphan transactions end up being included in the blockchain. Surprisingly, orphan transactions tend to have fewer parents on average than non-orphan transactions, and their missing parents have a lower fee, larger size, and lower transaction fee per byte than all other received transactions. Moreover, the network overhead incurred by these orphan transactions can be significant, exceeding 17% when using the default orphan memory pool size (i.e., 100 transactions), although this overhead can be made negligible, without significant computational or memory demands, if the pool size is simply increased to 1000 transactions. Finally, we show that when a node with an empty mempool first joins the network, 25% of the transactions that it receives become orphan, whereas in steady-state this quantity drops to about 1%.
Several recent studies have suggested Blockchain for Peer-to-Peer energy trading (P2P-ET) to achieve better security, privacy and fast payment settlement. Most of them however rely on either public Blockchains (which have low performance) or permissioned blockchains (which have low decentralization level and do not provide byzantine fault tolerance). Moreover, these solutions have limitations when capturing the business model of existing energy trading systems. This article proposes a Unified permissioned blockchain-based P2P-ET Architecture (UBETA) that integrates three different types of energy markets and provides a unified energy trading and payment settlement model. The UBETA system is based on an enterprise Ethereum Blockchain, known as Hyperledger Besu, and Istanbul Byzantine Fault Tolerance (IBFT) consensus algorithm. We compared the performance of the proposed IBFT-based system with three existing systems (i.e., Ethereum Clique, Ethereum Proof of Work and Hyperledger Fabric's Raft) using specific performance metrics (i.e., read/write transaction latency, read/write transaction throughput and fail rate). The experiments were carried out on a network size of up to 60 nodes and a real energy trading data set from the Western Australian energy market was used. The experiment results indicate that the IBFT-based system has 15x lower latency and nearly 2x throughput compared to existing Proof of Work based P2P-ET solutions. Moreover, the system provides better scalability and success rate than existing Raft based P2P-ET systems: the fail rate of the IBFT-based system only increased by 11% while that of Raft increased by 20% when increasing the number of nodes from 20 to 60. In addition, the proposed unified energy trading model provides lower latency and reduces the number of blockchain transactions compared to the non-unified counterpart.
This paper presents$\mathit {wChain}$, a blockchain protocol specifically designed for multihop wireless networks that deeply integrates wireless communication properties and blockchain technologies under the realistic SINR model. We adopt a hierarchical spanner as the communication backbone to address medium contention and achieve fast data aggregation within$O(\log N\log \Gamma)$slots where$N$is the network size and$\Gamma $refers to the ratio of the maximum distance to the minimum distance between any two nodes. Besides,$\mathit {wChain}$employs data aggregation and reaggregation as well as node recovery mechanisms to ensure efficiency, fault tolerance, persistence, and liveness. The worst-case runtime of$\mathit {wChain}$is upper bounded by$O(f\log N\log \Gamma)$, where$f=\lfloor \frac {N}{2} \rfloor $is the upper bound of the number of faulty nodes. To validate our design, we conduct both theoretical analysis and simulation studies. The results not only demonstrate the nice properties of$\mathit {wChain}$, but also point to a large new space for the exploration of blockchain protocols in wireless networks.
Aidana Kalakova, Arlan Zhanatbekov, Arkhat Surash, H. S. V. S. Kumar Nunna · 5 authors
This work proposes the use of blockchain technology to create a Decentralized Transactive Energy platform for Peer-to-Peer Energy Trading without authorized third-party agents. The distributed double auction mechanism is used in the proposed model as it enables every peer in the system to become an auctioneer, where the blockchain component will eliminate the single point of attack and guarantee the legal actions of all peers with the secure process of transactions. The main contribution of the paper is the combined use of Demand Response with a Decentralized Network. By considering optimal prosumer scheduling in the system, both preferences and needs of the peers in the network will be maximized. Experimental testing of the proposed strategy shows quick convergence of the decentralized auction, loss minimization caused by long transmission, improved security, and efficiency of the system.
A large number of consensus algorithms have been proposed. However, the requirement of strict consistency limits their wide adoption, especially in high-performance required systems. In this paper, we propose a weak consensus algorithm that only maintains the consistency of relative positions between the messages. We apply this consensus algorithm to construct a high-performance blockchain system, called \textit{Sphinx}. We implement the system with 32k+ lines of code including all components like consensus/P2P/ledger/etc. The evaluations show that Sphinx can reach a peak throughput of 43k TPS (with 8 full nodes), which is significantly faster than current blockchain systems such as Ethereum given the same experimental environment. To the best of our knowledge, we present the first weak consensus algorithm with a fully implemented blockchain system.
The Hashgraph consensus algorithm is an algorithm for asynchronous Byzantine fault tolerance intended for distributed shared ledgers. Its main distinguishing characteristic is it achieves consensus without exchanging any extra messages; each participant's votes can be determined from public information, so votes need not be transmitted. In this paper, we discuss our experience formalizing the Hashgraph algorithm and its correctness proof using the Rocq proof assistant. The paper is self-contained; it includes a complete discussion of the algorithm and its correctness argument in English.
Advancements in distributed ledger technologies are driving the rise of blockchain-based social media platforms such as Steemit, where users interact with each other in similar ways as conventional social networks. These platforms are autonomously managed by users using decentralized consensus protocols in a cryptocurrency ecosystem. The deep integration of social networks and blockchains in these platforms provides potential for numerous cross-domain research studies that are of interest to both the research communities. However, it is challenging to process and analyze large volumes of raw Steemit data as it requires specialized skills in both software engineering and blockchain systems and involves substantial efforts in extracting and filtering various types of operations. To tackle this challenge, we collect over 38 million blocks generated in Steemit during a 45 month time period from 2016/03 to 2019/11 and extract ten key types of operations performed by the users. The results generate SteemOps, a new dataset that organizes more than 900 million operations from Steemit into three sub-datasets namely (i) social-network operation dataset (SOD), (ii) witness-election operation dataset (WOD) and (iii) value-transfer operation dataset (VOD). We describe the dataset schema and its usage in detail and outline possible future research studies using SteemOps. SteemOps is designed to facilitate future research aimed at providing deeper insights on emerging blockchain-based social media platforms.
The number of Internet of Things (IoT) devices has increased recently and will increase further in the future. IoT devices are vulnerable, so vendors update and distribute firmware. At the time of firmware distribution, a huge number of IoT devices may connect to the firmware server and excessive network traffic may occur. Consequently, a method using a peer-to-peer file sharing system and a blockchain has been proposed. One study proposed an update scheme considering incentives for distributors to help with updating. However, this method requires the IoT devices, which have limited processing power, to decrypt encrypted files, and the distribution nodes to pay the transaction cost. This paper proposes a firmware distribution method that provides incentives for distributors to help with distribution to reduce the gas costs, using a smart contract and access control based on update records. The additional computations performed by IoT devices and distributors key management were reduced compared to those in previous studies by using access control instead of encryption. Further, the proposed approach was implemented and evaluated using a Raspberry Pi and laptop. The evaluation demonstrated that the gas cost per update was successfully lowered compared to the costs in previous studies.
The Internet of Things (IoT) is dominating every aspect of life. Smart homes, security systems, industrial automation, smart and intelligent power grids, etc. are important implementations of the IoT. It is an impactful addition to information and communication technology. As the IoT rises to the top, several issues emerge. Security, privacy, and vulnerability issues need to be addressed, to secure future IoT advancements. Blockchain technology is another tremendous addition to modern technology. Its decentralized architecture, distributed ledger, and cryptographic protection make this technology a potential integration element with other technologies, such as the IoT. Blockchain-enabled solutions for various IoT issues are the main aspect of this work. This chapter presents blockchain fundamentals and principles in detail, including blockchain-based IoT security solutions, with a comprehensive overview of the IoT architecture and its potential categorized security issues. The main motivation is to integrate blockchain in leveraging the issues of the IoT, as well as point out future research trends.
Xi Li, Zehua Wang, Victor C. M. Leung, Hong Ji · 6 authors
The paths leading to future networks are pointing towards a data-driven paradigm to better cater to the explosive growth of mobile services as well as the increasing heterogeneity of mobile devices, many of which generate and consume large volumes and variety of data. These paths are also hampered by significant challenges in terms of security, privacy, services provisioning, and network management. Blockchain, which is a technology for building distributed ledgers that provide an immutable log of transactions recorded in a distributed network, has become prominent recently as the underlying technology of cryptocurrencies and is revolutionizing data storage and processing in computer network systems. For future data-driven networks (DDNs), blockchain is considered as a promising solution to enable the secure storage, sharing, and analytics of data, privacy protection for users, robust, trustworthy network control, and decentralized routing and resource managements. However, many important challenges and open issues remain to be addressed before blockchain can be deployed widely to enable future DDNs. In this article, we present a survey on the existing research works on the application of blockchain technologies in computer networks, and identify challenges and potential solutions in the applications of blockchains in future DDNs. We identify application scenarios in which future blockchain-empowered DDNs could improve the efficiency and security, and generally the effectiveness of network services.
Sara Ghaemi, Sara Rouhani, Rafael Belchior, Rui Santos Cruz · 6 authors
The maturing of blockchain technology leads to heterogeneity, where multiple solutions specialize in a particular use case. While the development of different blockchain networks shows great potential for blockchains, the isolated networks have led to data and asset silos, limiting the applications of this technology. Blockchain interoperability solutions are essential to enable distributed ledgers to reach their full potential. Such solutions allow blockchains to support asset and data transfer, resulting in the development of innovative applications. This paper proposes a novel blockchain interoperability solution for permissioned blockchains based on the publish/subscribe architecture. We implemented a prototype of this platform to show the feasibility of our design. We evaluate our solution by implementing examples of the different publisher and subscriber networks, such as Hyperledger Besu, which is an Ethereum client, and two different versions of Hyperledger Fabric. We present a performance analysis of the whole network that indicates its limits and bottlenecks. Finally, we discuss the extensibility and scalability of the platform in different scenarios. Our evaluation shows that our system can handle a throughput in the order of the hundreds of transactions per second.
Peer-to-peer (P2P) energy management is one of the most viable solutions to incentivize prosumers in renewable energy microgrids. As the application of blockchain expends from the finance field to energy field, blockchain technology provides a new opportunity for distributed energy systems. However, a distributed energy system based on blockchains allows any node in the whole network to read data. In many application scenarios, user privacy cannot be effectively protected, and there is a security problem that the attack cannot be traced. In this paper, we propose an energy management mode based on a permissioned blockchain for a renewable energy microgrid. The novel permissioned blockchain framework uses entity mapping with a unique identity for each enterprise, natural person, or device, in order to avoid ineligible participants to join the microgrid. Each peer entity keeps the transaction information index of the whole network, but only keeps its own specific transaction information, so they can retrieve the transaction information of other peer entities but cannot obtain the details without permission. Moreover, this model could avoid communication delays and promote plug-and-play due to the distributed nature of the permissioned blockchain. The performance of the proposed method is evaluated with a demonstration program which is designed and deployed on a Hyperledger Fabric permissioned blockchain. Simulation results show the feasibility of the proposed method, and the model is conducive to the protection privacy and P2P energy management for decentralized energy systems.
Blockchain technology is reaching mainstream users due to its adoption by a large number of enterprises. Numerous new blockchain platforms and projects are emerging every year, intending to become the best blockchain. However, blockchain technology is far from reaching its full potential because of siloed blockchain platforms. Hence different blockchains should be able to interact with each other for carrying out data sharing and asset transfer among them. In this paper, we propose an approach for atomic cross-chain transfer among heterogeneous blockchains. We provide the implementation details and working of the proposed approach for different Ethereum blockchains.
Sivleen Kaur, Sheetal Chaturvedi, Aabha Sharma, Jayaprakash Kar
The concept of blockchain, widely known as virtual currencies, saw a massive surge in popularity in recent times. As far as the security of the blockchain is concerned, consensus algorithms play a vital role in the blockchain. Research has been done separately, or comparisons between a few of them have been presented previously. In this paper, we have discussed widely used consensus algorithms in the blockchain. The consensus protocols covered in this paper include PoW (Proof of Work), PoS (Proof of Stake), DPoS (Delegated Proof of Stake), PoET (Proof of Elapsed Time), PBFT (Practical Byzantine Fault Tolerance), and PoA (Proof of Authority). For each consensus, we have reviewed the properties, applications, and performance in the blockchain.
Mohammad Javad Amiri, Ziliang Lai, Liana Patel, Boon Thau Loo · 6 authors
We present Saguaro, a permissioned blockchain system designed specifically for edge computing networks. Saguaro leverages the hierarchical structure of edge computing networks to reduce the overhead of wide-area communication by presenting several techniques. First, Saguaro proposes coordinator-based and optimistic protocols to process cross-domain transactions with low latency where the lowest common ancestor of the involved domains coordinates the protocol or detects inconsistency. Second, data are collected over hierarchy enabling higher-level domains to aggregate their sub-domain data. Finally, transactions initiated by mobile edge devices are processed without relying on high-level fog and cloud servers. Our experimental results across a wide range of workloads demonstrate the scalability of Saguaro in supporting a range of cross-domain and mobile transactions.
The Bitcoin-Next Generation (NG) is a new blockchain protocol that is designed to scale the efficiency in terms of throughput and delay. Bitcoin-NG is a Byzantine fault-tolerant blockchain protocol robust to extreme churn and shares the same trust model as Bitcoin. Researchers are trying to extend their applications by integrating them with existing technologies, such as the Internet of Things (IoT). However, due to high computational power and high consensus delay, current blockchain protocols, such as Bitcoin, are not suitable for working with lightweight IoT devices. Moreover, they are not energy-efficient as the mining of blocks requires dedicated mining machines that consume electricity. However, protocols, such as Bitcoin-NG, are designed to reduce the consensus delay, but they still need high computational power and high energy. This article proposes a new mechanism for blockchain to reduce the consensus delay, reduce energy consumption, and increase the throughput by introducing a new leader election scheme in the blockchain.