P2P networks are the mechanism used by cryptocurrencies to disseminate system information while keeping the whole system as much decentralized as possible. Cryptocurrency P2P networks have new characteristics that propose new challenges and avoid some problems of existing P2P networks. By characterizing the most relevant cryptocurrency network, Bitcoin, we provide details on different properties of cryptocurrency networks and their similarities and differences with standard P2P network paradigms. Our study allows us to conclude that cryptocurrency networks present a new paradigm of P2P networks due to the mechanisms they use to achieve high resilience and security. With this new paradigm, interesting research lines can be further developed, both in the focused field of P2P cryptocurrency networks and also when such networks are combined with other distributed scenarios.
Gokhan Sagirlar, Barbara Carminati, Elena Ferrari, John Sheehan · 5 authors
From its early days the Internet of Things (IoT) has evolved into a decentralized system of cooperating smart objects with the requirement, among others, of achieving distributed consensus. Yet, current IoT platform solutions are centralized cloud based computing infrastructures, manifesting a number of significant disadvantages, such as, among others, high cloud server maintenance costs, weakness for supporting time-critical IoT applications, security and trust issues. Enabling blockchain technology into IoT can help to achieve a proper distributed consensus based IoT system that overcomes those disadvantages. While this is an ideal match, it is still a challenging endeavor. In this paper we take a first step towards that goal by designing Hybrid-IoT, a hybrid blockchain architecture for IoT. In Hybrid-IoT, subgroups of IoT devices form PoW blockchains, referred to as PoW sub-blockchains. Then, the connection among the PoW sub-blockchains employs a BFT inter-connector framework, such as Polkadot or Cosmos. In this paper, we focus on the PoW sub-blockchains formation, guided by a set of guidelines based on a set of dimensions, metrics and bounds. In order to prove the validity of the approach we carry on a performance and security evaluation.
There are several distributed ledger protocols potentially suitable for the Internet of things (IoT), including the Ethereum, Hyperledger Fabric and IOTA. This paper briefly presents and compares them from the IoT application development perspective. The IoT applications based on blockchain (BC) can incorporate the on-chain logic –the smart contracts– and Web, mobile or embedded client front-end application parts. We present three possible architectures for the IoT front-end BC applications. They differ in positioning of Ethereum blockchain clients (local device, remote server) and in positioning of key store needed for the management of outgoing transactions. The practical constraints of these architectures, which utilize the Ethereum network for trusted transaction exchange, are the data volumes, the location and synchronization of the full blockchain node and the location and the access to the Ethereum key store. Results of these experiments indicate that a full Ethereum node is not likely to reliably run on a constrained IoT devices. Therefore the architecture with remote Ethereum clients seems to be a viable approach, where two sub-options exist and differ in key store location/management. In addition, we proposed the use of architectures with a proprietary communication between the IoT device and remote blockchain client to further reduce the network traffic and enhance security. We expect it to be able to operate over low-power, low-bitrate mobile technologies, too. Our research clarifies differences in architectural approaches, but final decision for a particular ledger protocol and front-end application architecture is at strongly based on the particular intended use case.
Traditional centralized commerce on the Internet relies on trusted third parties to process electronic payments. It suffers from the weakness of the trust-based model. A pure decentralized mechanism called blockchain tackles the above problem and has become a hot research area. However, since each node in a blockchain system needs to store all transactions of the other nodes, as time continues, the storage room required to store the entire blockchain will be huge. Therefore, the current storage mechanism needs to be revised to cater to the rapidly increasing need for storage. Network coded (NC) distributed storage (DS) can significantly reduce the required storage room. This paper proposes a NC-DS framework to store the blockchain and proposes corresponding solutions to apply the NC-DS to the blockchain systems. Analysis shows that the proposed scheme achieves significant improvement in saving storage room.
F. Richard Yu, Jianmin Liu, Ying He, Pengbo Si · 5 authors
Recently, with the tremendous development of crypto-currencies, distributed ledger technology (DLT) (e.g., blockchain) has attracted significant attention. The traditional Internet was originally design to handle the exchange of information. With DLT, we will have the Internet of value. Although, DLT has a great potential to create new foundations for our economic and social systems, the existing DLT has a number of drawbacks (e.g., scalability) that prevent it from being used as a generic platform for distributed ledger across the globe. In this paper, we present a novel virtualization approach to address the challenges in the existing DLT systems. Specifically, in the proposed virtualization for DLT (vDLT), the underlying resources (e.g., hardware, compute, storage, network, and so on) are abstracted. By providing a logical view of resources, vDLT can significantly improve the performance, facilitate system evolution, and simplify DLT management and configuration. Several use cases of vDLT are presented to illustrate the effectiveness of the proposed vDLT.
Michel Rauchs, Andrew Glidden, Brian Gordon, Gina Pieters · 8 authors
The DLT ecosystem is plagued with the use of incomplete and inconsistent definitions and a lack of standardised terminology, creating a needlessly complicated landscape for everyone from experienced policymakers and developers to individuals venturing into the field for the first time. This study sets out to contribute to international discussions to create a shared, common language around DLT systems to clarify terminology and concepts.
Open access
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Open Source Software Innovations
Transportation and Mobility Innovations
Innovative Approaches in Technology and Social Development
Wei Cai, Zehua Wang, Jason B. Ernst, Zhen Hong · 6 authors
Blockchain technology has attracted tremendous attention in both academia and capital market. However, overwhelming speculations on thousands of available cryptocurrencies and numerous initial coin offering (ICO) scams have also brought notorious debates on this emerging technology. This paper traces the development of blockchain systems to reveal the importance of decentralized applications (dApps) and the future value of blockchain. We survey the state-of-the-art dApps and discuss the direction of blockchain development to fulfill the desirable characteristics of dApps. The readers will gain an overview of dApp research and get familiar with recent developments in the blockchain.
Blockchain has numerous benefits such as decentralisation, persistency, anonymity and auditability. There is a wide spectrum of blockchain applications ranging from cryptocurrency, financial services, risk management, internet of things (IoT) to public and social services. Although a number of studies focus on using the blockchain technology in various application aspects, there is no comprehensive survey on the blockchain technology in both technological and application perspectives. To fill this gap, we conduct a comprehensive survey on the blockchain technology. In particular, this paper gives the blockchain taxonomy, introduces typical blockchain consensus algorithms, reviews blockchain applications and discusses technical challenges as well as recent advances in tackling the challenges. Moreover, this paper also points out the future directions in the blockchain technology.
Oğuzhan Ersoy, Zhijie Ren, Zekeriya Erkin, Reginald L. Lagendijk
Existing permissionless blockchain solutions rely on peer-to-peer propagation mechanisms, where nodes in a network transfer transaction they received to their neighbors. Unfortunately, there is no explicit incentive for such transaction propagation. Therefore, existing propagation mechanisms will not be sustainable in a fully decentralized blockchain with rational nodes. In this work, we formally define the problem of incentivizing nodes for transaction propagation. We propose an incentive mechanism where each node involved in the propagation of a transaction receives a share of the transaction fee. We also show that our proposal is Sybil-proof. Furthermore, we combine the incentive mechanism with smart routing to reduce the communication and storage costs at the same time. The proposed routing mechanism reduces the redundant transaction propagation from the size of the network to a factor of average shortest path length. The routing mechanism is built upon a specific type of consensus protocol where the round leader who creates the transaction block is known in advance. Note that our routing mechanism is a generic one and can be adopted independently from the incentive mechanism.
Adoption of Cryptocurrency has grown significantly over the time and becoming more popular among young generation. People are calling it currency of new digital era. In this research work we are reviewing the dominant Cryptocurrency systems and its underlying disruptive Innovations and Technologies.
Ethereum, a cryptocurrency currently valued at 46 billion US dollars, has grown over 6,500% in the last 12 months. Despite the growth in value, we still have very limited Ethereum network visibility. In this thesis, we analyze the Ethereum network from two vantage points: the DEVp2p network and the Ethereum Mainnet. The DEVp2p peer-to- peer (P2P) network was developed specifically for and ultimately underlies the Ethereum Mainnet. We examine overall composition of the DEVp2p network. We analyze our peer connections on the Ethereum Mainnet—the main Ethereum network established on top of DEVp2p. We compare the Ethereum network’s properties to those of other well-studied P2P networks, namely BitTorrent and Gnutella. We develop novel techniques to measure the Ethereum P2P network and gain visibility into this previously opaque network.
Ali Dorri, Salil S. Kanhere, Raja Jurdak, Praveen Gauravaram
BlockChain (BC) has attracted tremendous attention due to its immutable nature and the associated security and privacy benefits. BC has the potential to overcome security and privacy challenges of Internet of Things (IoT). However, BC is computationally expensive, has limited scalability and incurs significant bandwidth overheads and delays which are not suited to the IoT context. We propose a tiered Lightweight Scalable BC (LSB) that is optimized for IoT requirements. We explore LSB in a smart home setting as a representative example for broader IoT applications. Low resource devices in a smart home benefit from a centralized manager that establishes shared keys for communication and processes all incoming and outgoing requests. LSB achieves decentralization by forming an overlay network where high resource devices jointly manage a public BC that ensures end-to-end privacy and security. The overlay is organized as distinct clusters to reduce overheads and the cluster heads are responsible for managing the public BC. LSB incorporates several optimizations which include algorithms for lightweight consensus, distributed trust and throughput management. Qualitative arguments demonstrate that LSB is resilient to several security attacks. Extensive simulations show that LSB decreases packet overhead and delay and increases BC scalability compared to relevant baselines.
Dec 1, 2017·2017 IEEE 19th International Conference on High Performance Computing and Communications; IEEE 15th International Conference on Smart City; IEEE 3rd International Conference on Data Science and Systems (HPCC/SmartCity/DSS)
Domain name system is an essential component of the Internet, but is facing numerous security threats. On the other hand, blockchain has been widely used since Bitcoin. Theoretically, most of the decentralized system can be rebuilt using blockchain. Namecoin and Blockstack have made attempts to combine domain name service with blockchain, but have defects in security and performance. In this paper, we propose a new domain name service based on a consortium chain network which contains query nodes and miner nodes. To address the storage challenge of blockchain, the system is designed with three-layer architecture and additional external storage. In addition, the system builds index for transactions and blocks to speed up domain name resolution and incorporates gossip protocol to synchronize blocks between different nodes.
Dec 1, 2017·2017 IEEE International Symposium on Parallel and Distributed Processing with Applications and 2017 IEEE International Conference on Ubiquitous Computing and Communications (ISPA/IUCC)
With the development of ICT industry, the volume of produced data is experiencing tremendous growth, which motivates more demands of storage capacity. Because of the limited storage capacity of users' terminals, more and more applications prefer to upload data to cloud platforms. However, it is well known that security should not be neglected in existing cloud storage architectures. Motivated by the increasing popularity of emerging blockchain technology, we propose a blockchain-based security architecture for distributed cloud storage. Moreover, we customize a genetic algorithm to solve the file block replica placement problem between multiple users and multiple data centers in the distributed cloud storage environment. Numerical experimental results show that the proposed architecture outperforms the traditional cloud storage architectures in terms of security, with acceptable network transmission delay.
Government information resource (GIR) sharing, an important means for efficient government working, requires new technology to enhance its reliability and security. Blockchain, as an emerging technology for building decentralized applications, is gradually penetrating various fields. In this paper, we present a technical combination that consists of Blockchain structure, network sharing model and consensus algorithms. With these techniques, we design and implement a Blockchain-based GIR sharing system (BGIRSS), which is decentralized, to make the sharing procedure more efficient. The results of a series of emulational experiments show that our system is securer and more reliable than conventional sharing schemes, and can effectively promote the sharing efficiency of GIRs with lower implementation cost.
Digital Currency for Central Bank is becoming an important policy for country. CBDC (Central Bank Digital Currency) model should take advantages in the supervision, payment and consumption. Blockchain possesses the feature of de-centrality, tamper-resistant, and traceability. So this paper attempts to use the blockchain as the fundamental technology of CBDC. However, the challenges such as the protection for users privacy, supervision and transaction speed should be overcome. This paper proposes a CBDC model called MBDC which is based on the permission blockchain technology. The model makes use of the multi-blockchain architecture and ChainID to improve the models scalability and process payments more quickly. In this model, central bank and commercial banks and other agencies build and maintain the blockchain. On one hand, central bank could master the issuance of currency. On the other hand, relying on the user account address protocol, central bank could separate the users identity and transaction information. In this way, central bank could avoid double-spending issues and protect users privacy. In addition, the establishment of DC (Data Center) and layers of supervision provide strong supervision for the model. Finally, we also demonstrate, both theoretically and experimentally, the performance of model on the scalability and the speed of transaction execution etc.
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
Dec 1, 2017·2017 IEEE 19th International Conference on High Performance Computing and Communications; IEEE 15th International Conference on Smart City; IEEE 3rd International Conference on Data Science and Systems (HPCC/SmartCity/DSS)
Bitcoin introduces a revolutionary decentralized consensus mechanism. However, Bitcoin-derived consensus mechanisms applied to public blockchain are inadequate for the deployment scenarios of budding consortium blockchain. We propose a new consensus algorithm, Proof of Vote (POV). The consensus is coordinated by the distributed nodes controlled by consortium partners which will come to a decentralized arbitration by voting. The key idea is to establish different security identity for network participants, so that the submission and verification of the blocks are decided by the agencies' voting in the league without the depending on a third-party intermediary or uncontrollable public awareness. Compared with the fully decentralized consensus-Proof of Work (POW), POV has controllable security, convergence reliability, only one block confirmation to achieve the transaction finality, and low-delay transaction verification time.
Following the success of Bitcoin, Ethereum and Hyperledger, blockchains are now gaining widespread adoption in a wide variety of applications, using a diversity of distributed ledger systems with varying characteristics. Yet, beyond the original bitcoin protocol, the safety and reliability properties of such systems are not sufficiently analyzed. To better understand the behavior of these systems, we propose VIBES: a configurable blockchain simulator for large scale peer-to-peer networks. With VIBES, users can explore important characteristics and metrics of the network, reason about interactions between nodes, and compare different scenarios in an intuitive way. VIBES differentiates itself from previous works in its ability to simulate blockchain systems beyond bitcoin and its support for large-scale simulations with thousands of nodes.
IPFS [1] is a peer-to-peer version controlled filesystem that synthesizes learnings from many previous successful systems. IPFS combines a distributed Hash table, an incentivized block exchange, and a self-certifying namespace [1]. IPFS is a peer-to-peer hypermedia protocol to make the web faster, safer, and more open. According to the characteristics of IPFS, we propose an improved P2P file system scheme based on IPFS and Blockchain. We address the high-throughput problem for individual users in IPFS by introducing the role of content service providers. Consider data reliability and availability, storage overhead and other issues for service providers, we provide a novel zigzag-based storage model to improve the block storage model that IPFS provides. Moreover, we introduce blockchain to combine IPFS with this storage model. According to analysis, this proposed scheme can effectively solve the above problems.
Bitcoin has not only attracted many users but also been considered as a technical breakthrough by academia. However, the expanding potential of Bitcoin is largely untapped due to its limited throughput. The Bitcoin community is now facing its biggest crisis in history as the community splits on how to increase the throughput. Among various proposals, Bitcoin Unlimited recently became the most popular candidate, as it allows miners to collectively decide the block size limit according to the real network capacity. However, the security of BU is heatedly debated and no consensus has been reached as the issue is discussed in different miner incentive models. In this paper, we systematically evaluate BU's security with three incentive models via testing the two major arguments of BU supporters: the block validity consensus is not necessary for BU's security; such consensus would emerge in BU out of economic incentives. Our results invalidate both arguments and therefore disprove BU's security claims. Our paper further contributes to the field by addressing the necessity of a prescribed block validity consensus for cryptocurrencies.
Blockchain uses the idea of storing transaction data in the form of a distributed ledger wherein each node in the network stores a current copy of the sequence of transactions in the form of a hash chain. This requirement of storing the entire ledger incurs a high storage cost that grows undesirably large for high transaction rates and large networks. In this work we use the ideas of secret key sharing, private key encryption, and distributed storage to design a coding scheme such that each node stores only a part of the entire transaction thereby reducing the storage cost to a fraction of its original cost. When further using dynamic zone allocation, we show the coding scheme can also improve the integrity of the transaction data in the network over current schemes. Further, block validation (bitcoin mining) consumes a significant amount of energy as it is necessary to determine a hash value satisfying a specific set of constraints; we show that using dynamic distributed storage reduces these energy costs.
Nelson Bore, Samuel Karumba, Juliet Mutahi, Shelby S. Darnell · 6 authors
Several initiatives have been proposed to collect, report, and analyze data about school systems for supporting decision-making. These initiatives rely mostly on self-reported and summarized data collected irregularly and rarely. They also lack a single independent and systematic process to validate the collected data during its entire lifecycle. Furthermore, schools in developing countries still do not maintain complete and up-to-date school records. Due to these and other factors addressing the education challenges in those countries remains a high priority for local and international governments, donor and non-governmental agencies across the world. In this paper, we discuss our initial design, implementation, and evaluation of a blockchain-enabled School Information Hub (SIH) using Kenya's school system as a case study.