As the number of blockchain (BC) platforms providing specific features increases, selecting a platform that fits all requirements needed for a specific case becomes a cumbersome task. For example, not only are BCs' technical details relevant, but also their intrinsic characteristics (e.g., cryptocurrency price) must be considered in selecting a BC for a given case. Hence, the management of data stored in multiple BCs and the selection process are not straightforward due to the myriad platforms and both technical and economic details (e.g., BC throughput and the underlying price fluctuation). This article defines a novel refinement flow (based on the policy continuum) of high-level BC selection policies to low-level BC transactions. Experiments with the BC selection framework developed applying policy-based management (PBM) in the BC context do show that such synergy simplifies data management in multiple BCs driven by user requirements (e.g., based on costs or performance policies). The performance analysis of the framework demonstrates the successful employment of PBM for BC selections with minimal overhead.
Qianyun Gong, Chengjin Zhou, Le Qi, Jianbin Li · 6 authors
The payment channel networks (PCNs), as the main method of blockchain off-chain expansion, have received extensive attention in recent years. Using the PCNs, two unconnected parties in a transaction can forward payments through existing payment channels of other nodes, which dramatically reduces interactions with the blockchain. But in large-scale dynamic PCNs, the routing mechanism is a challenge. Existing PCNs routing algorithms have some limitations. The landmark routing destroys the decentralization of blockchain. The static routing requires nodes having a global view and ultra-high computing power, which can not be applied to light nodes. We propose VEIN, a dynamic multi-path source routing algorithm, which is suitable for not only full nodes but also light nodes. We present an ingenious routing protocol, a modified max-flow algorithm to find edge-disjoint paths, and a path selection algorithm to deal with the NP-hard multi-path selection problem. Extensive experiments show that VEIN increases the transaction success ratio by 34% with the state-of-art algorithm, and realizes multiple orders of magnitude reduction in storage. In addition, we implement a prototype of VEIN on the Ethereum testnet to verify its feasibility.
Cesar E. Castellon, Swapnoneel Roy, Patrick Kreidl, Ayan Dutta · 5 authors
Blockchain-powered smart systems deployed in different industrial applications promise operational efficiencies and improved yields, while mitigating significant cybersecurity risks pertaining to the main application. Associated tradeoffs between availability and security arise at implementation, however, triggered by the additional resources (e.g., memory, computation) required by each blockchain-enabled host. This paper applies an energy-reducing algorithmic engineering technique for Merkle Tree root calculations, a principal element of blockchain computations, as a means to preserve the promised security benefits but with less compromise to system availability. Using pyRAPL, a python library to measure computational energy, we experiment with both the standard and energy-reduced implementations of the Merkle Tree for different input sizes (in bytes). Our results show up to 98% reduction in energy consumption is possible within the blockchain's Merkle Tree construction module, such reductions typically increasing with larger input sizes. The proposed energy-reducing technique is similarly applicable to other key elements of blockchain computations, potentially affording even “greener” blockchain-powered systems than implied by only the Merkle Tree results obtained thus far.
Ethereum Blockchain based Smart Contracts are computer programs that enable decentralized transactions among its participants. The development of smart contracts is a complex process because of the characteristics of Blockchain Technology like the immutability of blocks added to the blockchain. Also, the current evolving nature of this novice technology makes the development process insubstantial. Therefore, this doctoral dissertation highlights the vulnerabilities and complexities in smart contracts and proposes a model-driven engineering framework for designing secure smart contracts at the model level and generating vulnerability-free smart contract code.
Ethereum as one of the largest blockchain systems plays an important role in the distributed ledger, database systems, etc. As more and more blocks are mined, the storage burden of Ethereum is significantly increased. The current Ethereum system uniformly transforms all its data into key-value (KV) items and stores them to the underlying Log-Structure Merged tree (LSM-tree) storage engine ignoring the software semantics. Consequently, it not only exacerbates the write amplification effect of the storage engine but also hurts the performance of Ethereum. In this paper, we proposed a new Ethereum-aware storage model called Block-LSM, which significantly improves the data synchronization of the Ethereum system. Specifically, we first design a shared prefix scheme to transform Ethereum data into ordered KV pairs to alleviate the key range overlaps of different levels in the underlying LSM-tree based storage engine. Moreover, we propose to maintain several semantic-orientated memory buffers to isolate different kinds of Ethereum data. To save space overhead, Block-LSM further aggregates multiple blocks into a group and assigns the same prefix to all KV items from the same block group. Finally, we implement Block-LSM in the real Ethereum environment and conduct a series of experiments. The evaluation results show that Block-LSM significantly reduces up to 3.7× storage write amplification and increases throughput by 3× compared with the original Ethereum design.
Bitcoin Edge Exact exchanging and simple payouts are a certain something, yet client care can frequently represent the moment of truth any business. The client care and client security gave by Bitcoin Edge is ironclad. You don't host to stress over a third gathering getting to your private data on the stage which is basic for any monetary program. In the event that you do require help, the client support entrance of Bitcoin Edge offers speedy reaction times and exact help.\n\n \n\nhttps://www.bitcoinedge.app/\nhttps://www.facebook.com/bitcoinedge/\nhttps://twitter.com/bitcoinedge_app\nhttps://www.pinterest.co.uk/bitcoinedge/\nhttps://www.instagram.com/bitcoinedge/\n\n \n\n
Integrating blockchain into software solutions is not straightforward as it requires sophisticated architectural design to connect and orchestrate centralized elements, such as backend logic, with decentralized elements, such as blockchain ledgers and smart contracts. We systematically explore this design space and possible architectural solution approaches. More specifically, we provide architectural blue prints for applications with different degrees of decentralization, describe conceptional components as well as possible relations between them. Our research shows that an event-driven architecture incorporating a messaging framework, tethered to dedicated components for handling blockchain state-changing and state-collecting operations, is a prevalent approach for choreographing blockchain-dependent business logic in blockchain-based applications.
Blockchain and Distributed Ledger Technology (DLT) appears to be at a worldwide threshold of acceptance and adoption. Since their inception, several innovative projects have been proposing solutions to the blockchain trilemma, improving blockchain features and its technical limitations. However, the adoption of blockchain as a technology or a software component, requires a comprehensive understanding and characterization of their technical principles and characteristics. The latter introduces an uncertainty for an organization to decide which blockchain protocol best meets its needs and demands. In general, there is a lack of proper testing and software engineering practices for assessing the usage of blockchains usage and understanding their performance. Towards that direction, this paper presents an architecture for a blockchain benchmarking framework which aims at the deployment and evaluation of different blockchain protocols, focusing on different aspects such as security and scalability. A set of modules is introduced for testing and evaluating the behaviour of blockchain protocols under different test scenarios.
Blockchain-based smart contracts provide transparent automation in a broad range of services, including finance, the Internet of Things, and autonomous systems. However, the implementation of such services may easily involve security risks and functional errors, especially for complex services composed of different blockchains. To help developers focus on their business model instead of diving into the blockchain architecture heterogeneity, we propose a framework to enable analysis and comparison of composed services before deployment. This is achieved through the intensive use of model-based engineering allowing reasoning on the model before generating concrete deployment artifacts, especially for the safe orchestration of contract calling transactions.
Matea Vasilj, Sven Skender, Mia Jurdana, Marko Horvat
Student non-profit organizations are a specific type of small associations that congregate students from diverse backgrounds around a common purpose. These organizations are non-profit driven, autonomous, and typically have largely similar statutes and regulations. In the context of software engineering, information systems that support their business processes have similar software requirements specifications. DESPRO is a web-based platform that fully supports principal use cases of students' non-profit organizations. The platform has three uses: accounting, voting, and fundraising management. DESPRO allows such organizations to begin with their principal operations practically immediately without unnecessary overhead. Unique features that distinguish DESPRO from other similar systems are: 1) lightweight and streamlined deployment process, 2) minimal required remote maintenance, 3) pre-defined functionalities specifically suited for student non-profit organizations, 4) user anonymity customized to specific functional requirements, 5) voting without prior user registration. The platform was developed with open-source technologies Node.js, Vue.js, Vuetify, Bootstrap, Sequalize, Axios, Web3, MariaDB, and smart contracts for Ethereum. It is freely available for noncommercial use by contacting the first author.
Akshay M. Fajge, Siddharth Thakur, Rahul Kumar, Raju Halder
With the advancement of blockchain technology at a breakneck pace, numerous organizations are now experimenting with blockchain solutions for their operations. In this nascent stage, due to the scarcity of blockchain domain experts, there is a growing trend towards an automated conversion of legacy systems to blockchain-based systems. To this aim, this paper presents an automated framework that facilitates the migration of centralized Java-based applications to decentralized Solidity-based Ethereum applications. The experimental results are encouraging, demonstrating its ability to handle large-scale Java codebase. To the best of our knowledge, this is the first proposal of its kind that enables the translation of Java source codes to Solidity source codes.
Levy Marlon Souza Santiago, Jauberth Weyll Abijaude, Fabíola Greve
Blockchain is a disruptive technology that offers a secure decentralized network, and allows for direct transactions between distributed entities, without the need for a trusted third party. Smart contracts are executable codes hosted on the blockchain and enable the implementation of several decentralized applications, in different domains. However, due to the complexity of contract construction, it is necessary to seek ways to facilitate and make this innovative development process robust. This paper presents Gifflar, a framework for generating smart contract code on the fly, in such a way that it allows a system to write, compile and implement blockchain contracts with a decentralized application still running. Gifflar is structured in components that implement design patterns to better define the responsibility of each one of the parts and exports a simple interaction module for contract modeling in JSON and automatic code writing using the TypeScript language. As far as we know, this framework is one of the first to generate contracts dynamically at run time. Thus, the work contributes to the state of the art by addressing a new paradigm, where systems can act as smart contract developers.
Michał Król, Onur Ascigil, Sergi Reñé, Alberto Sonnino · 6 authors
We propose Shard Scheduler, a system for object placement and migration in account-based sharded blockchains. Our system calculates optimal placement and decides on object migrations across shards. It supports complex multi-account transactions caused by smart contracts. Placement and migration decisions made by Shard Scheduler are fully deterministic, verifiable, and can be made part of the consensus protocol. Shard Scheduler reduces the number of costly cross-shard transactions, ensures balanced load distribution and maximizes the number of processed transactions for the blockchain as a whole. To this end, it leverages a novel incentive model motivating miners to maximize the global throughput of the entire blockchain rather than the throughput of a specific shard. In our simulations, Shard Scheduler can reduce the number of costly cross-shard transactions by half while ensuring equal load and increasing throughput more than 2 fold when using 60 shards. We also implement and evaluate Shard Scheduler on Chainspace, more than doubling its throughput and reducing user-perceived latency by 70% when using 10 shards.
Lightweight blockchain inherits the advantages of traditional blockchain, while avoiding excessive reliance on computing and storage resources, and has already been applied in IoV system. This paper combines the characteristics of IoV and node distribution, and proposes a lightweight blockchain architecture oriented to vehicles-road-cloud-server(V2R2CS) collaboration based on the existing lightweight blockchain architecture. Cooperating caching and Block Filtered Algorithm are used to allow road side units(RSUs) to cooperatively store and search blocks, which will further reduce the delay of blockchain query in IoV system. Finally, the simulation experiment proves the feasibility of the algorithm and the good real-time requirement.
In this paper we describe LUNES-Blockchain, an agent-based simulator of\nblockchains that relies on Parallel and Distributed Simulation (PADS)\ntechniques to obtain high scalability. The software is organized as a\nmulti-level simulator that permits to simulate a virtual environment, made of\nmany nodes running the protocol of a specific Distributed Ledger Technology\n(DLT), such as the Bitcoin or the Ethereum blockchains. This virtual\nenvironment is executed on top of a lower-level Peer-to-Peer (P2P) network\noverlay, which can be structured based on different topologies and with a given\nnumber of nodes and edges. Functionalities at different levels of abstraction\nare managed separately, by different software modules and with different time\ngranularity. This allows for accurate simulations, where (and when) it is\nneeded, and enhances the simulation performance. Using LUNES-Blockchain, it is\npossible to simulate different types of attacks on the DLT. In this paper, we\nspecifically focus on the P2P layer, considering the selfish mining, the 51%\nattack and the Sybil attack. For which concerns selfish mining and the 51%\nattack, our aim is to understand how much the hash-rate (i.e. a general measure\nof the processing power in the blockchain network) of the attacker can\ninfluence the outcome of the misbehaviour. On the other hand, in the filtering\ndenial of service (i.e. Sybil Attack), we investigate which dissemination\nprotocol in the underlying P2P network makes the system more resilient to a\nvarying number of nodes that drop the messages. The results confirm the\nviability of the simulation-based techniques for the investigation of security\naspects of DLTs.\n
Enterprise Resource Planning (ERP) software is extensively used for the management of business processes. ERP offers a system of integrated applications with a shared central database. Storing all business-critical informatio... | Find, read and cite all the research you need on Tech Science Press
Aeri Kim, Jungyeon Kim, Meryam Essaid, Sejin Park · 5 authors
Bitcoin is a blockchain-based network where thousands of nodes are directly connected and communicate through a gossip-based flooding protocol. Mined blocks are propagated to all participating nodes in the network through compact block relay (CBR) protocol. Therefore, reducing the block relay time between nodes can reduce the block propagation time to all nodes and ultimately improve the performance of Bitcoin. In order to reduce the block relay time, the delivery time between nodes must be measured and analyzed to find the cause of the delay and provide ways to resolve it. Therefore, in this paper, we measure the CBR time between directly connected Bitcoin nodes and analyze the cause of the relay delay. Our results show that the delivery time delay is affected by whether or not a transaction is requested when assembling the compact block. In addition, the reason for requesting a transaction is due to the transaction propagation method and the characteristics of the transaction itself.
Selma Steinhoff, Chrysoula Stathakopoulou, Matej Pavlovič, Marko Vukolić
Reconfiguration of long-lived blockchain and Byzantine fault-tolerant (BFT) systems poses fundamental security challenges. In case of state-of-the-art Proof-of-Stake (PoS) blockchains, stake reconfiguration enables so-called long-range attacks, which can lead to forks. Similarly, permissioned blockchain systems, typically based on BFT, reconfigure internally, which makes them susceptible to a similar "I still work here" attack. In this work, we propose BMS (Blockchain/BFT Membership Service) offering a secure and dynamic reconfiguration service for BFT and blockchain systems, preventing long-range and similar attacks. In particular: (1) we propose a root BMS for permissioned blockchains, implemented as an Ethereum smart contract and evaluate it reconfiguring the recently proposed Mir-BFT protocol, (2) we discuss how our BMS extends to PoS blockchains and how it can reduce PoS stake unbonding time from weeks/months to the order of minutes, and (3) we discuss possible extensions of BMS to hierarchical deployments as well as to multiple root BMSs.
Since Bitcoin was launched, the blockchain technology and the cryptocurrencies have been in the spotlight. Ethereum, the second-generation blockchain introduced smart contracts, and many DApps have emerged due to them. Those DApps showed the feasibility of blockchain in various industries. However, even though the growth of blockchain technology, still many DApps are based on Ethereum, and supper its performance issue. Since the performance evaluation in Ethereum mainnet is almost impossible, and there are no formalized performance evaluation frameworks, it is hard to perform appropriate performance evaluation of Ethereum. Detail performance evaluations on Ethereum networks are essential for developing and operating DApps. In this paper, we use Hyperledger Caliper, an automated performance evaluation framework to evaluate an Ethereum private network, and the Ropsten testnet to overcome above problems. We evaluate the performance with a specific smart contract and analyze the results. Our evaluation results show that the Ethereum private network performs better than the Ropsten testnet, and the Ropsten testnet is unstable for performance evaluation. In addition, our results show that the performance of the transactions can differ following their content.
Smart contracts, scripts at the heart of blockchain-based applications, are meant to be available forever once deployed. However, this property has a price. The amount of space required to store new contracts keeps increasing. This increase impacts each participating node's performance and makes it inconvenient for low-end devices to participate in the network. Among all contracts deployed in the blockchain, a vast majority will lead to little if any usage. We demonstrate that, in the course of one year, 70 % of deployed contracts lead to no use. Unfortunately, unused contracts keep occupying space on the blockchain. To tackle this issue, we propose a new protocol to identify and delete unused contracts. Through simulation, based on Ethereum historical data, we show that deletion of smart contracts after an inactivity period of 90 days could lead to a 66 % reduction in the number of contracts stored over a year.
Blockchain is not widely applied in various fields due to the critical issue of scalability as part of the blockchain trilemma. This issue arises during consensus among the nodes in a public blockchain. To address the issue of low scalability with proof-of-work (PoW) consensus, various methods have been proposed for transaction per second (TPS) improvement. However, no such methods include an improvement in the consensus step. Therefore, to improve PoW public blockchain scalability, it is important to shorten the time required for PoW consensus. This paper proposes a method for minimizing the block intervals that occur during consensus over a PoW blockchain network. A shortened block interval leads to an increase in the probability of three different attacks: selfish mining, double-spending, and eclipse attacks. According to an experiment using Ethereum, with a typical PoW blockchain, it is inevitable to provide rewards for stable block mining in competition between mining pools. To find an optimal block interval in the PoW consensus algorithm, we conducted a four-step experiment. The purpose of this experiment was to verify the difficulty level and issues with Mainnet security. Therefore, considering stale block mining rewards, an optimal block interval is proposed. The Ethereum TPS was improved by at least 200%. Given this finding, it is considered possible to achieve a similar improvement in a different PoW blockchain. On balance, even if the block interval is shorter than that of the PoW Mainnet, network security falls by only 1.21% in Testnet, even with a rise in the stale block rate, while performance is increased at up to 120 TPS, which is three times higher than that in Mainnet.
Thieu Nguyen, Thang Trung Nguyen, Vu Quoc Hien, Thi Thanh Binh Huynh · 5 authors
In this paper, we first design a system that integrates a blockchain network into a fog-cloud environment to improve the transparency as well as avoid the attack from suspicious parties. We identify task scheduling as the most prominent and crucial issue in such a system and model it as a multi-objective optimization problem. To solve this problem, we propose a multi-objective version of the Sparrow Search Algorithm (SSA), called MO-SSA. Our experimental studies compare MO-SSA with other well-known optimization algorithms (NSGA-II, NSGA-III, and MO-ALO). Results show that MO-SSA archives better results than most of the baseline algorithms on several performance metrics.