As a common cryptocurrency platform, Ethereum involves massive accounts and numerous real-time transactions. Moreover, as the involved accounts increase drastically, it is impossible to have transactions among all accounts at one time slot, which results in a high-dimensional and incomplete (HDI) dynamic transaction network. In spite of its HDI nature, such HDI dynamic transaction network contains much useful knowledge regarding involved accounts' behavior patterns like potential transaction links. To extract such knowledge from an HDI dynamic transaction network, this paper proposes a Non-negative Adaptive Latent Factorization of Tensors (NAL) model with two interesting ideas: a) adopting an HDI tensor to describe an HDI dynamic transaction network and building a non-negative learning objective based on the principle of data density-oriented, and b) implementing model hyper-parameter self-adaptive via using a particle swarm optimization (PSO) algorithm in the training process. Empirical studies on three real Ethereum transaction networks show that compared with state-of-the-art methods, the proposed NAL model achieves superior performance in terms of accuracy and computational efficiency in predicting potential transaction links.
Wireless service providers (WSPs) are seeking cooperation to share both resources (spectrum, infrastructures) and costs. In particular, cooperation is critical for vehicle-to-everything (V2X) applications that value quality-of-service foremost. However, cooperation is inefficient without strong trust bases. Recently, blockchain arises as a promising solution to decentralized trust, owing to its transparency and immutability. Therefore, we propose a WSP cooperation framework based on blockchain, which keeps a shared ledger on resource utilization. In this paper, we first study the WSP selection problem of vehicles by evolutionary game. Then, we make the blockchain public to vehicles to maintain its decentralization and enhance its security by crowdsourcing idle computing resources from vehicles. To deal with the mobility of vehicles, as well as to improve the consensus efficiency, we propose delegated proof-of-work (DPoW) scheme, which introduces delegate nodes for participating in the blockchain consensus on behalf of the vehicles. The alternating direction method of multipliers (ADMM) optimization framework is further used to derive optimal consensus parameters including block size, computing resource demand of delegate nodes, and prices paid for vehicles. We conduct extensive simulations to show the effectiveness of the proposed methods.
Md. Nasim Uddin, Abu Hayat Mohammed Abul Hasnat, Shamima Nasrin, Md. Shahinur Alam · 5 authors
People are dependent on Trusted Third Party (TTP) administration based Centralized systems for content sharing having a deficit of security, faith, immutability, and clearness. This work has proposed a file-sharing environment based on Blockchain by clouting the Interplanetary File System (IPFS) and Public Key Infrastructure (PKI) systems, advantages for overcoming these troubles. The smart contract is implemented to control the access privilege and the modified version of IPFS software is utilized to enforce the predefined access-control list. An application framework on a secure decentralized file sharing system is presented in combination with IPFS and PKI to secure file sharing. PKI having public and private keys is used to enable encryption and decryption of every file transaction and authentication of identities through Metamask to cryptographically recognize account ownership in the Blockchain system. A gas consumption-based result analysis is done in the private Ethereum network and it attains transparency, security managed access, and quality of data indicating better efficacy of this work.
With increasing local energy generation consumers are converting into prosumers by selling their excess generation with their peers. This transaction of locally generated energy is called Peer-to-Peer (P2P) energy trading. For P2P energy trading, a community system is widely endorsed but causes an increase in overall system cost as both prosumer and consumer need to pay charges to the community manager. In this context, a hybrid P2P energy trading market is implemented through a decentralized blockchain-based mechanism. It permits market participants to trade energy directly without involving an additional entity. Contracts play a crucial role in blockchain-based energy trading mechanisms. Thus, smart contracts are designed for the efficient implementation of this trading mechanism. These contracts are designed using the Solidity platform on REMIX IDE. Prosumer and consumer interact among themselves through the main smart contract to execute P2P energy trading till market-clearing time. Afterwards, they interact with the grid through Peer-to-Grid (P2G) smart contracts for additional sell/purchase of energy. Results show that the proposed approach leads to a smart, secure and economical mechanism of energy trading.
Muntadher Sallal, Gareth Owenson, Dawood Salman, Mo Adda
Bitcoin is a digital currency based on a peer-to-peer network to propagate and verify transactions. Bitcoin is gaining wider adoption than any previous crypto-currency. However, the mechanism of peers randomly choosing logical neighbours without any knowledge about the underlying physical topology can cause a delay overhead in information propagation which makes the system vulnerable to double spend attacks. Aiming at alleviating the propagation delay problem, this paper introduces a proximity-aware extension to the current Bitcoin protocol, named Master Node Based Clustering (MNBC). The ultimate purpose of the proposed protocol, which is based on how clusters are formulated and how nodes can define their membership, is to improve the information propagation delay in the Bitcoin network. In the MNBC protocol , physical internet connectivity increases as well as the number of hops between nodes decreases through assigning nodes to be responsible for maintaining clusters based on physical Internet proximity. Furthermore, a reputation-based blockchain protocol is integrated with MNBC protocol in order to securely assign a master node for every cluster. We validate our proposed methods through a set of simulation experiments and the findings show how the proposed methods run and their impact in optimising the transaction propagation delay.
Ananda Rizky Duto Pamungkas, Diyanatul Husna, F. Astha Ekadiyanto, I Ketut Eddy Purnama · 10 authors
In this study, a higher level of security was implemented by using InterPlanetary File System (IPFS) based peer-to-peer data storage on an Ethereum blockchain. IPFS is used as an image data storage medium that generates an IPFS hash, or known as content identifier (CID). The CID is used to access image data on the IPFS, which can be done with the help of an IPFS gateway. The CID is sent into the blockchain using a smart contract. The results of the study demonstrates that the use of IPFS as additional security on a blockchain system can be done. The size of file sent using IPFS proportionally affects the time it takes for IPFS to store the file. The larger the file size, the more time it will take. For each additional 1 MB file, there is an approximately 5% increase in access time. The distance from the IPFS gateway will also affect file access times in which, the farther the IPFS gateway, the more time it takes. If the IPFS gateway is at a distance of 1,000 km, there will be a decrease in access time of about 5%. The distance between the IPFS gateway and the accessor also affects success with accessing data. For the most distant gateway, i.e. the United States, there was even an access failure of 24%.
Recently, blockchain radio access network (B-RAN) arises as an innovative paradigm for the sixth-generation (6G) wireless communications to build cooperative trust, aggregate wireless resources, and schedule inter- and intra-network tasks among independent network entities. It establishes an open platform based on blockchain to provide diverse wireless services and applications, such as radio access, Internet of Things (IoT), and mobile-edge computing, via trusted interactions with enhanced security and efficiency. As a distinctive feature, B-RAN enables secure and efficient resource sharing and trading by aggregating, pooling, and coordinating resources from multiple resource hosts and owners across subnetworks. Therefore, an implementable architecture along with various functional modules shall be delicately designed. This work aims to establish a unified architecture with enhanced efficiency, security, compatibility, and flexibility for resource sharing and trading in B-RAN. Specifically, we develop a six-layer architecture that incorporates a number of novel features, such as enhanced blockchain structures, secure interaction methods, efficient service mechanisms, and scalable transaction patterns. We design a number of pluggable functional modules in each layer to support diverse functions, services, and applications of resource sharing and trading. Finally, we implement a practical prototype based on the layered architecture for resource-limited devices. Multiple experiments are presented to verify the performance of the proposed architecture from different aspects.
Lightweight nodes in the Bitcoin network do not have the capability to synchronize the entire contents of the blockchain. In order to receive information that is relevant to them, they use the Simplified Payment Verification (SPV) protocol to communicate with full nodes, that hold the entire blockchain. Bloom filters are used by the SPV protocol to mitigate known privacy issues. Still, the effectiveness of using Bloom filters comes into question. In this paper, we analyze the behaviour of Bloom filter requests with respect to their target False Positive Rate (FPR) values. Our findings show that small FPR values have very limited bandwidth requirements, while higher values are not suitable for use with bandwidth restricted devices. At the same time, we confirm that privacy implications of Bloom filters are still valid today, when an increasing number of new addresses appears in the Bitcoin blockchain every day. We also study the effect that multiple concurrent requests made by Bloom filter enabled lightweight clients have on the disk and CPU utilization, as well as RAM consumption of full node clients.
Yoshito Watanabe, So Hasegawa, Mikio Hasegawa, Yozo Shoji
This paper proposes a novel framework for transaction record management using distributed ledger technology over the “piggy-back network”, which is an opportunistic network composed of mid-range control plane and short-range data plane with heterogeneous wireless standards. In the network, mobile nodes such as service robots perform sensing by, e.g., recording video and try to disseminate the large-volume sensing data contents to other nodes via the data plane by a store-carryforward (SCF) principle. To manage the transaction records that represent event histories in the network, we employ a distributed ledger, where our previously proposed Proof-of-Forwarding (PoF) technique is used for block generation; a block is generated at the timing of completing data exchange. We design the ledger to have a directed acyclic graph (DAG) structure to work in an opportunistic network. By synchronizing the ledgers between nodes over the control plane, every node can grasp the differences of the databases owned by individual nodes, and this knowledge is utilized to determine if the node-to-node data exchange via the data plane is necessary. The computer simulations show that, compared to a conventional blockchain, the proposed DAG-based ledger can achieve a lower delay for disseminating transaction records across all nodes. In contrast, large delays are caused in a conventional blockchain system due to its single-branch structure.
In modern times, the definition and the library’s expected functionality did not change much as before. It is still a place for us to hold massive collections of information. Traditionally, libraries require physical storage space for writings and publications, but storing and managing costs can be tremendous. Although the aid of digital promises and computers allows a super high density of information storage, it does not lower the library’s complexity. As our main source of information is moving away from physical writings toward digital, the new digital library (i.e., state-run library) faces the challenges of records’ integrity and storage efficiency. Focused on this issue, we learn the demands from the Royal Library in Denmark and try to explore the use of blockchain technology. We introduce a system named LibBlock, by integrating with both smart contract and IPFS in order to provide a robust, decentralized, flexible, and adaptive e-Library, which enables the ease of scalability and rigid record keeping. In the evaluation, we investigate the initial performance of LibBlock with Ethereum and show its viability and efficiency.
Kaja Schmidt, Alexander Mühle, Andreas Grüner, Christoph Meinel
The current Self-Sovereign Identity (SSI) ecosystem is rapidly changing and ill-defined. Manifold actors, projects, and initiatives produce different SSI solutions, frameworks, protocols, and distributed ledgers. Even though some patterns exist among SSI ecosystem members, no elaborate systematization has been made. This paper conducts a systematic gray literature review to structure the SSI ecosystem. Specifically, we derive a four-dimensional taxonomy that portrays members of the SSI ecosystem. Then, we classify the ecosystem members into eight archetypes. The goals are to allow researchers to describe SSI ecosystem members, help new and existing members locate themselves within the SSI ecosystem, and provide an overview of members’ functionalities. We find that SSI ecosystem members either govern the SSI ecosystem and/or networks, implement SSI offerings, or support governing and/or implementing members. The study suggests that, as the SSI ecosystem grows, the number of governing members will grow slower than the number of implementing and supporting members.
Anwar Said, Muhammad Umar Janjua, Saeed‐Ul Hassan, Zeeshan Muzammal · 8 authors
Ethereum, the second-largest cryptocurrency after Bitcoin, has attracted wide attention in the last few years and accumulated significant transaction records. However, the underlying Ethereum network structure is still relatively unexplored. Also, very few attempts have been made to perform link predictability on the Ethereum transactions network. This paper presents a Detailed Analysis of the Ethereum Network on Transaction Behavior, Community Structure, and Link Prediction (DANET) framework to investigate various valuable aspects of the Ethereum network. Specifically, we explore the change in wealth distribution and accumulation on Ethereum Featured Transactional Network (EFTN) and further study its community structure. We further hunt for a suitable link predictability model on EFTN by employing state-of-the-art Variational Graph Auto-Encoders. The link prediction experimental results demonstrate the superiority of outstanding prediction accuracy on Ethereum networks. Moreover, the statistic usages of the Ethereum network are visualized and summarized through the experiments allowing us to formulate conjectures on the current use of this technology and future development.
This work introduces a novel approach for the governance of a blockchain containing social constructs and technical viability for widescale applications for the next generation of distributed ledgers. Functional requirements for this new blockchain distributed ledger (BDL) were garnered from an analysis of the needs for large-scale applications. Applied research was employed as part of this endeavor to test the practicality and scalability of the solution outline. Novel features in this application draw together controls and enforcement for cybersecurity, digital content management, licensing, and configuration management. The Synchronous Trust Consensus Model applied research project named Project Philos was sponsored by the BlockChain Development Community (BCDC) with support from the University of Colorado. Research has followed both theorized conceptual and theory-to-practice models to prove the scientific soundness and the viability of incentive for community engagement. Results show that this new model proves the feasibility of an indefinitely expandable blockchain distributed ledger capability, while also providing a new participant incentive that is highly effective in engaging a community of practitioners.
Direct transactions between prosumers without a central authority is allowed by the peer-to-peer energy trading market. Blockchain technology is considered as the optimal system to support P2P transactions and provide the internal payment platform. Miners as a significant role are motivated by the financial incentive to maintain the blockchain operation. This paper proposes a consortium blockchain system under Proof-of-Stake (PoS) consensus protocol to maintain the security and transparency of the energy transactions and a mining-rewarding mechanism to lower trading cost. The structure of the proposed blockchain as well as its implementation process are discussed in this paper. The results of a case study prove the effectiveness and feasibility of the proposed blockchain based method.
Runkai Yang, Xiaolin Chang, Jelena Mišić, Vojislav B. Mišić
Bitcoin and Ethereum are the top two blockchain-based cryptocurrencies whether from cryptocurrency market cap or popularity. However, they are vulnerable to selfish mining and stubborn mining due to that both of them adopt Proof-of-Work consensus mechanism. In this paper, we develop a novel Markov model, which can study selfish mining and seven kinds of stubborn mining in both Bitcoin and Ethereum. The formulas are derived to calculate several key metrics, including relative revenue of miners, blockchain performance in terms of stale block ratio and transactions per second, and blockchain security in terms of resistance against double-spending attacks. Numerical analysis is conducted to investigate the quantitative relationship between the relative-revenue-optimal mining strategy for malicious miners and two miner features in Bitcoin and Ethereum, respectively. The quantitative analysis results can assist honest miners in detecting whether there is any malicious miner in the system and setting the threshold of mining node's hash power in order to prevent malicious miners from making profit through selfish and stubborn mining.
Chitturi Prasad, Gummuluri Udaya Chandrika, Vani Venkata Sai Sindhu Garapati, Ganga Rama Koteswara Rao · 6 authors
Immutability is a term used a lot in blockchain and cryptocurrency development when attemptingto analyze the economic interpretation of a network. Designs like the 21 million Bitcoin supply in BTC or incidents like the DAO fork bailout that split the Ethereum community into ETH and ETC are major examples of immutability values determining the ethos of a chain. This research sets out tocategorize different features of blockchain immutability and analyze them in three different networks: Bitcoin (BTC), Ethereum (ETH), and Ethereum Classic (ETC). Further in the paper, the Finney Ratio is introduced to help understand how blockchain immutability can be measured over time. The paper then visualizes overall blockchain immutability over time using radar charts as an immutability map. The Szabo Score is then introduced as a tool to score overall mutability over time for each blockchain.
In this paper, we present a plugin for visualising vote based consensus\nmechanisms primarily aimed to help engineers understand and debug blockchain\nand distributed ledger protocols. Both tools are built as Grafana plugins and\nmake no assumptions on the data storage implementation. The plugins can be\nconfigured via Grafana plugin configuration interface to fit the specifics of\nthe protocol implementation.\n
Xinyu Ye, Meng Li, F. Richard Yu, Pengbo Si · 6 authors
Nowadays, the rise of the Internet of Vehicles (IoV) has led to the rapid development of smart transportation. To increase the computing capacity of mobile vehicles and decrease the content delivery latency of suppliers, mobile edge computing (MEC) is considered as an indispensable solution. However, there are some essential issues to be considered: 1) security and privacy of data transmission, and 2) reasonable resource allocation for collaborative computing and caching. In this paper, to solve above issues, blockchain technology is adopted to ensure reliable transmission and interaction of data. Meanwhile, we develop an intelligent resource framework about computing and caching for blockchain-enabled MEC systems in IoV. Through jointly considering and optimizing offloading decision of computation task carried by vehicle, caching decision, the number of offloaded consensus nodes, block interval and block size, the energy consumption and computation overheads can be decreased, and the data throughput of the blockchain can be increased significantly. Moreover, the proposed optimization problem is modeled and formulated as a Markov decision process. Facing the complexity and dynamic of resource allocation, the asynchronous advantage actor-critic approach is considered and applied to solve the optimization problem. Experiment results demonstrate that the advantages of the proposed optimization scheme are obvious compared with other existing schemes.
Evolution of the cellular network has created many new capabilities that were previously unavailable in the legacy standards. High throughput and low latency communications are the hallmark of the new 5G-NR standard. Caching at the D2D layer in 5G presents tremendous opportunity for further enhancement of the 5G standard and could be the driving factor behind new set of verticals to be offered and made available over 5G and Beyond 5G (B5G) networks.Smart contracts, applications deployed on a distributed blockchain, similarly provide a huge range of novel opportunities in programming and managing a distributed network system while maintaining security. Since D2D communications are fundamentally limited by their localized communication, a smart contract based approach is presented here to open up the D2D layers in B5G networks to any content provider or network operator participating in the shared blockchain network. In this work, three different priority models are evaluated for performance with respect to caching decisions driven by a genetic algorithm based search for decision optimality. Findings suggest that integration of a priority scheme with a smart contract enforced caching at D2D layer significantly influences the Radio Access Network (RAN) performance in terms of the cost and delay for proposed D2D wireless network.
Since version 0.11 of Bitcoin Core, a user can run a full node in pruning mode, i.e. a pruned node, in resource-limited devices. The pruned node is a lightweight full node as it can independently verify new transactions and blocks received from other peers in the Bitcoin network by only maintaining some recently verified blocks (not the complete blockchain) and the complete Unspent Transaction Output (UTXO) set. However, the rapid increase in the size of the UTXO set has caused the main part of the UTXO set to be stored in the low-speed disk, and thus slows down the verification speed of new blocks in lightweight full nodes. Existing verification schemes for pruned nodes do not take advantage of the fact that different UTXO-related transactions are included in a new block with different probabilities, resulting in poor verification performance. In this paper, we propose a prediction-based UTXO cache optimization mechanism to increase the verification speed of new blocks. In order to achieve higher prediction accuracy and reduce the memory requirements of UTXO set, we first design a method to synchronize unconfirmed transactions for lightweight full nodes to ensure that the local and miners' unconfirmed transaction sets are highly consistent. Then, a lightweight full node predicts which unconfirmed transactions will have a greater probability of appearing in the new block by utilizing the fact that most miners will prioritize unconfirmed transactions to maximize the total transaction fee when mining a new block. Based on this mechanism, we can pre-load the UTXOs required for new block verification into the memory, thereby greatly improving the verification performance. Experimental results show that the proposed mechanism can accelerate the block verification of lightweight full nodes with small memory requirements.
Xueqiang Yan, Xueli An, Wenxuan Ye, Mingyu Zhao · 5 authors
The subscriber data management locates at the heart of the mobile network by providing identity management and granting subscriber access to various network services. The subscriber data is usually stored in the core network, the handling of which shall be compliant with regulatory requirements on data protection. Inspired by the current research on the privacy issues of Internet applications, this work is the first attempt to consider data management from mobile network architecture perspective with the goal of making data processing natively transparent. This work proposes a novel subscriber data management scheme based on the combination of Distributed Ledger Technology (DLT) and Distributed Hash Table (DHT) technologies. Moreover, corresponding procedures are defined to ensure subscriber’s control over personal subscription data (including authentication data) by implementing authentication, authorization and access control in the blockchain platform. To avoid blockchain bloat and privacy issues caused by transparency of blockchain, off-chain data storage architecture is adopted, and is realized in the form of DHT for its expressive features like scalability and look-up speed.
Blockchain Technology Applications and Security
Caching and Content Delivery
Advanced Steganography and Watermarking Techniques
Non-Fungible Token (NFT) has garnered remarkable attention to decentralized digital asset management. Permissionless blockchains store NFT content data leveraging P2P storage networks, in which data resource flows subject to financial incentives. For permissioned blockchains, without incentives, the placement of content data to the storage network requires a sound strategy, including the placement process and the replica location strategy, to avoid problems such as communication cost excess and storage unfairness, which greatly limit the service efficiency and sustainability of the storage network. Therefore, in this paper, we propose a new collaboration model between blockchain and the P2P storage network for issuing a new NFT, in which blockchain can complete the placement process and promote rational data distribution in the P2P storage network. Our proposed replica location strategy mainly considers three factors: storage fairness, service efficiency, and business load. Through theoretical analysis and experiments, it is proved that our replica location strategy has a better performance in both fairness and efficiency.