The major challenges of operating data-intensive of Distributed Ledger Technology (DLT) are (1) to reach consensus on the main chain as a set of validators cast public votes to decide on which blocks to finalize and (2) scalability on how to increase the number of chains which will be running in parallel. In this paper, we introduce a new proximal algorithm that scales DLT in a large-scale Internet of Things (IoT) devices network. We discuss how the algorithm benefits the integrating DLT in IoT by using edge computing technology, taking the scalability and heterogeneous capability of IoT devices into consideration. IoT devices are clustered dynamically into groups based on proximity context information. A cluster head is used to bridge the IoT devices with the DLT network where a smart contract is deployed. In this way, the security of the IoT is improved and the scalability and latency are solved. We elaborate on our mechanism and discuss issues that should be considered and implemented when using the proposed algorithm, we even show how it behaves with varying parameters like latency or when clustering.
Olamide Jogunola, Mohammad Hammoudeh, Kelvin Anoh, Bamidele Adebisi
The increasing integration of prosumers and smart metering devices into the energy distribution network, is transforming the traditional energy market to a community energy trading that requires peer-to-peer (P2P) interactions. Such P2P interactions result in complex data exchanges among prosumers, utility grid, and market operators. This inevitably introduces control complexity, security, and privacy challenges in the existing power system. The application of distributed ledger technology (DLT) has seen an increase in solving security challenges in the power network, specifically, in P2P energy exchanges. Thus, this study explores different DLT structures including blockchain and IOTA usage in energy P2P trading. A smart contract for managing trust and transactions is designed and implemented on IBM hyperledger fabric platform. In addition, we evaluated the performance of interconnected internet of things devices for energy transactions with IOTA protocol, which uses the directed acyclic graph as its DLT structure, against the Ethereum-based blockchain structure. It is shown that the end-to-end transaction delay with the IOTA DLT is lower than the Ethereum-based DLT implementation.
In this paper, we investigated the evolution of the External owned account Trading Network(ETN) on Ethereum from August 10th, 2015 to June 9th, 2017 through the perspective of network science. It is showed that the evolution of the topological properties of the ETN and important events are closely related. The average degree of the ETN is not constant but fluctuates within a small range of (2.1, 3.2). And there exists the extremely strongly positive correlation between the number of nodes and the number of edges in the ETN. Moreover, following the events happening, the degree distribution of ETN changes obviously. Moreover, the ETN has smaller values of degree correlation coefficient and clustering coefficient than that of the randomized graph with the same degree sequence, which implies that ETN shows the disassortative mixing pattern by degree and owns few triangles. Through the method of k-shell decomposition, our investigation shows the core of the ETN grows stepwise.
Koushik Bhargav Muthe, Khushboo Sharma, Karthik Epperla Nagendra Sri
The market value of the Gaming industry was said to be over 138 Billion USD in 2019. Competitive Gaming or eSports was already included in the Asian Games 2020, and the Olympic committee is considering including eSports into Olympics 2024. The online gaming segment amounts up to 7 quintillion bytes of internet traffic every month. Most of this data is controlled by centralized gatekeepers like cloud agencies and game creators. This is causing many issues ranging from privacy concerns to latency. The game makers have complete rights over the game to arbitrarily change the rules, set prices for the assets, and control over game servers. Even the reward mechanisms in most of the games, including eSports, are controlled by the game producers, and these rewards have no real-world value. The motivation behind this research is to create a decentralized computation and token management infrastructure for game networks. This paper focuses on using Ethereum Blockchain, IPFS and ERC - Ethereum Request for Comment 1155 architecture to build a gaming-oriented public decentralized network.
The lightning network (LN) is a special network in Bitcoin that uses offchain micropayment channels to scale the blockchain's capability to perform instant transactions without a global block confirmation process. However, micropayment scalability in a large LN and liquidation for small nodes still remain major challenges for the LN. In this paper, we introduce the notion of supernodes and the corresponding supernodes-based pooling to address these challenges. In order to meet the high adaptivity and low maintenance cost in the dynamic LN where users join and leave, supernodes are constructed locally without any global information or label propagation. Each supernode, together with a subset of (non-supernodes) neighbors, forms a supernode-based pool. These pools constitute a partition of the LN. Additionally, supernodes are self-connected. Micro-payment scalability is supported through node set reduction as only supernodes are involved in searching and in payment with other supernodes. Liquidation is enhanced through pooling to redistribute funds within a pool to external channels of its supernode. Extensive simulations have been conducted to validate the improvement in routing scalability and liquidation of the proposed architecture under different settings.
Conventional blockchain implementations with append-only semantics do not support deleting or overwriting data in confirmed blocks. However, many industry-relevant use cases require the ability to delete data, especially when personally identifiable information is stored or when data growth has to be constrained. Existing attempts to reconcile these contradictions compromise on core qualities of the blockchain paradigm, as they include backdoor-like approaches such as central authorities with elevated rights or usage of specialized chameleon hash algorithms in chaining of the blocks. The contribution of this paper is a novel architecture for the blockchain ledger and consensus, which uses a tree of context chains with simultaneous validity. A context chain captures the transactions of a closed group of entities and persons, thus structuring blocks in a precisely defined way. The resulting context isolation enables consensus-steered deletion of an entire context without side effects to other contexts. We show how this architecture supports truncation, data rollover and separation of concerns, how the GDPR regulations can be fulfilled by this architecture and how it differs from sidechains and state channels.
On top of subscription-based pricing models such as Software-as-a-Service (SaaS), monetizing the subscription enables the payment of data streams with data usage instead of a particular price for a fixed data set. This pricing model allows data providers to have a better vision of managing budgets and data consumers to have the flexibility to subscribe and unsubscribe. However, unlike static data collections, the streaming data increases difficulties of dynamic data ownership and identity verification. A trustless data trading infrastructure is required where the entities can trade, validate data ownership and data integrity without trusting any service or participants. In addition, an automated subscription procedure is also demanded for the sake of data monetization. In this paper, we leverage usages of distributed ledger technologies (DLTs) to construct a decentralized data trading platform on top of the IoT brokered infrastructure. This approach can efficiently enhance the degree of transparency and scalability. The storage built upon cryptographic message protocols allows transmitting, accessing and validating data streams over distributed ledgers without authorities, and the digital rights of trading participants deserve a guarantee, which is enabled by design.
Renato Vargas-Gomez, Juan Carlos Pérez-Arriaga, Jorge Octavio Ocharán-Hernández, Ángel J. Sánchez-García
Distributed Ledger Technologies (DLT) open new opportunities for data protection since they bring decentralization and sovereignty over the ownership of data. On the practical side, implementations of this technology are limited. Due to its novelty, the fundamentals for their design and development are still emerging. An essential feature of DLT is the consensus mechanism, which is used so that the members of the DLT network validate and append data to the ledger. The design decision of which mechanism to use will significantly impact the functionality of the system. Therefore, it is a decision that cannot be taken lightly. Software engineers, developers, and other practitioners in the field can use the knowledge and understanding of the implementations that already exist to help with these decisions. This paper presents the results of a multivocal literature review carried out to identify the consensus mechanisms used in DLT for the protection of confidential data. Twenty-seven studies were selected; in those studies, twenty-one different consensus mechanisms were identified. The review showcases the mechanisms that have been identified and their contexts, alongside a discussion of their relevance and characteristics.
The Bitcoin P2P network is at the core of all communications between clients. The reachable part of this network has been explored and analyzed by numerous studies. Unreachable nodes, however, are, in most part, overlooked. Nonetheless, they are a relevant part of the network and play an essential role in the propagation of messages. In this paper, we focus on transaction propagation and show that increasing the participation of unreachable nodes can potentially improve the robustness and efficiency of the network. In order to do that, we propose a few changes to the network protocol. Additionally, we design a novel transaction propagation protocol that explicitly involves unreachable nodes to provide better protection against deanonymization attacks. Our solutions are simple to implement and can effectively bring immediate benefits to the Bitcoin network.
The Bitcoin P2P network is at the core of all communications between clients.\nThe reachable part of this network has been explored and analyzed by numerous\nstudies. Unreachable nodes, however, are, in most part, overlooked.\nNonetheless, they are a relevant part of the network and play an essential role\nin the propagation of messages. In this paper, we focus on transaction\npropagation and show that increasing the participation of unreachable nodes can\npotentially improve the robustness and efficiency of the network. In order to\ndo that, we propose a few changes to the network protocol. Additionally, we\ndesign a novel transaction propagation protocol that explicitly involves\nunreachable nodes to provide better protection against deanonymization attacks.\nOur solutions are simple to implement and can effectively bring immediate\nbenefits to the Bitcoin network.\n
Off-chain transaction networks can mitigate the scalability issues of today's trustless blockchain systems such as Bitcoin. However, these peer-to-peer networks also introduce a new attack surface which is not yet fully understood. This paper identifies and analyzes a novel type of Denial-of-Service attack which is based on attracting routes, i.e., which exploits the way transactions are routed and executed along the channels of the network in order to attract nodes to route through the attacker. This attack is conceptually interesting as it highlights a fundamental design tradeoff for the defender (who determines its own routes): to become less susceptible to hijacking, a rational node has to pay higher fees to nodes that forward its payments.
David Cordova Morales, Alexandre Laubé, Thi Mai Trang Nguyen, Guy Pujolle
Blockchain is one of the most prominent emerging technologies. It offers the ability to maintain an anti-tamper distributed database, ensuring the integrity and authenticity of data in a decentralized system. However, when using blockchain in a dynamic community, such as mobile nodes in an ad hoc and mesh networks, the chain structure is no longer enough to deal with node mobility. In this paper, we address the challenges of using a DAG-based blockchain for mobile and ad hoc networks (MANETs) that we call “blockgraph”. We define the characteristics of the blockgraph framework. This includes: the requirement needed for a consensus protocol in order to be resilient to network partitions; the specifications of the blockgraph protocol that ensure the maintenance of the blockgraph data structure; and a group management system that reacts to network topology changes that provide with relevant network topology information to the blockgraph framework. Finally, we implemented our framework in the discrete event network simulator NS3 as a proof-of-concept for our blockgraph.
In this demo, we present SEBDB, a novel blockchain database that integrates immutability and transparency properties of blockchain with modeling and query ability of relational database. In summary, SEBDB has the following advantages: First, it adopts the linked structure and full replication of data among multiple participants to guarantee immutability and transparency. Second, it introduces the relational model to blockchain without introducing extra overhead, based on which relational queries are supported. SEBDB supports SQL-like language as the general interface to support convenient application development, in which intrinsic operations are re-defined and re-implemented to suit for blockchain platform. Third, it supports rich verifiable queries based on the proposed authenticated index, thin clients can participate in the system regardless of limitations of storage, network, and computing resources. We demonstrate the usability and scalability of SEBDB using a donation system.
Crowdsourcing can improve productivity by distributing tasks to the public. However, the traditional crowd-sourcing system has some problems. We have implemented a novel crowdsourcing system based on blockchain, which can solve the single point of failure. considering the risk of data loss in a centralized system, we complete data storage based on ipfs and propose a data access control method for ipfs. When disputes occurred during the crowdsourcing process, the traditional method was to decide results by the centralized platform, which may lead to unfairness. We innovatively apply the quadratic voting to the crowdsourcing system. And for the sybil attack in the voting, the process of voting was improved. The experimental results prove the feasibility of the crowdsourcing system.
Bryan Wolff, Diego Fernandes Gonçalves Martins, Marco Aurélio Amaral Henriques
A blockchain é um sistema de registro seguro e distribuído que necessita de um mecanismo de consenso capaz de definir quais novos blocos são inseridos à cadeia, a medida que são produzidos pelos participantes da rede. A análise da evolução de uma blockchain controlada por um novo mecanismo de consenso pode ser complexa. Para simplificar tal análise, este artigo apresenta o desenvolvimento de uma nova ferramenta para monitoramento da evolução dinâmica de uma blockchain. É apresentada em detalhes a arquitetura da mesma e sua integração com o protocolo Probabilistic Proof-of-Stake (PPoS).
The success of Bitcoin and Ethereum has attracted many efforts to build high-throughput blockchain systems. This paper focuses on transaction dissemination --- a rather overlooked issue in these systems. We argue that efficient transaction dissemination is the key for a blockchain system to sustain at high-throughput --- usually thousands of transactions per second --- and the existing solutions fell short at doing so.
Oct 8, 2020·Proceedings of the Twenty-First International Symposium on Theory, Algorithmic Foundations, and Protocol Design for Mobile Networks and Mobile Computing
Bitcoin is undoubtedly the most used distributed ledger technology nowadays. Bitcoin's OP_RETURN operator allows for saving arbitrary data on the blockchain. This comes as an extension of Bitcoin's core usage (i.e. cryptocurrency) and opens up a multitude of use cases. These range from benign applications (e.g. ownership of a digital/physical asset) to illegal/malicious scenarios (e.g. blockchain-based botnets). In this paper, we present a system that provides advanced analytic and visual capabilities with regard to the OP_RETURN operator. Furthermore, we showcase a quantitative and qualitative analysis of the OP_RETURN along with a number of interesting findings.
Blockchain Technology Applications and Security
Peer-to-Peer Network Technologies
Advanced Steganography and Watermarking Techniques
It is widely accepted that Ethereum mining is highly centralized.\nNonetheless, centralization has been mostly characterized by exclusively\nlooking at the influence that independent miners or mining pools can have over\nthe network. Moreover, models of mining behavior assume that miners are either\nunrelated or only relate via mining pools under highly structured and\ntransparent agreements. If these assumptions and the predictions they entail\nwere to be completely accurate, there would not be any evidence of on-chain\ntransactions between miners, other than the ones expected from mining pool\npayouts. By looking at on-chain transactions between miners in the Ethereum\nNetwork we find that aside from the payouts from mining pools to small miners,\nthere are also transactions that define relationships between mining pools,\nindependent miners and between independent miners and mining pools.\nFurthermore, by characterizing the topology of the network of miner\ntransactions, we find the emergence of highly connected clusters that control\nsignificant amounts of hashing power and exhibit relationships in the opposite\ndirection of what theoretical models predict. This more nuanced\ncharacterization of mining centralization can help identify network\nvulnerabilities and inform protocol redesigns.\n
Oct 8, 2020·Proceedings of the Twenty-First International Symposium on Theory, Algorithmic Foundations, and Protocol Design for Mobile Networks and Mobile Computing
Navin V. Keizer, Onur Ascigil, Ioannis Psaras, George Pavlou
Traversing NAT's remains a big issue in P2P networks, and many of the previously proposed solutions are incompatible with truly decentralised emerging applications. Such applications need a decentralised NAT traversal solution without trusted centralised servers.
Ethereum is the typical representative of the second generation of Blockchain technology. To achieve anonymity and decentralization, Ethereum utilizes a structured P2P network for data broadcasting, replication, and synchronization. The Ethereum P2P network topology construction profoundly affects the overall Ethereum system performance and reliability. However, there are few studies on the Ethereum underlying P2P overlay network topology. In this paper, we perform a preliminary investigation on this extensive Ethereum P2P system with a comprehensive measurement method combining active and passive methods. We gather Ethereum nodes information by active method for nodes crawling and verification, and we use the passive network traffic monitoring for routing data gathering. After a period of data collection for more than one month, we get a massive data set that has more than 50 million routing data entries. This data set allows us to gain knowledge on the Ethereum network scale and to derive mathematical characteristics of overlay network structure. By analyzing the data set comprehensively, we find that the Ethereum network exhibits both small-world and scale-free characteristics. There are a few critical nodes that have a significant impact on the robustness and vulnerability of the whole system. The Ethereum network also has a very high concentration in terms of network routing, which is very vulnerable to routing attacks.
Distributed Ledger Technology (DLT) currently stands in the limelight. In many people's eyes, DLT has great potential to accelerate the digitalization process and substantially change the roles and services of central banks. On the other hands, as many new applications for DLT spring up, there isn't an assessment framework to evaluate DLT applied in the financial industry, leaving those systems to be easily under attack. This paper presents an initial DLT assessment framework for financial application. Through a suite of benchmarks, we show the evaluation results and explore the factors which affect the performance and security of DLT application.
The peer-to-peer (P2P) network of blockchain used to transport its transactions and blocks has a high impact on the efficiency and security of the system. The P2P network topologies of popular blockchains such as Bitcoin and Ethereum, therefore, deserve our highest attention. The current Ethereum blockchain explorers (e.g., Etherscan) focus on the tracking of block and transaction records but omit the characterization of the underlying P2P network. This work presents the Ethereum Network Analyzer (Ethna), a tool that probes and analyzes the P2P network of the Ethereum blockchain. Unlike Bitcoin that adopts an unstructured P2P network, Ethereum relies on the Kademlia DHT to manage its P2P network. Therefore, the existing analytical methods for Bitcoin-like P2P networks are not applicable to Ethereum. Ethna implements a novel method that accurately measures the degrees of Ethereum nodes. Furthermore, it incorporates an algorithm that derives the latency metrics of message propagation in the Ethereum P2P network. We ran Ethna on the Ethereum Mainnet and conducted extensive experiments to analyze the topological features of its P2P network. Our analysis shows that the Ethereum P2P network possesses a certain effect of small-world networks, and the degrees of nodes follow a power-law distribution that characterizes scale-free networks.