A blockchain based system integrity (BCSI) framework for assuring the integrity of information system processes is presented. BCSI is well suited for a broad class of large scale real-world information systems. Under the BCSI framework, the integrity of any information system I is assured by executing the finite state machine model for system I processes in a blockchain network. The BCSI framework is compared and contrasted with the Clark-Wilson (CW) system integrity model, and existing blockchain based frameworks like Ethereum.
The relationship between customers, Facility managements and Utility companies can be a challenge. The persistent lack of trust leads to a fraud doubts, disputes and arbitration which results are expensive. Such kind of issues generate expenses for all participants. We have developed three models based on Hyperledger Fabric and we have revealed different difficulties in an every one. Usage of Distributed Ledger Technology based solutions will bring a real value to all actors in the system.
Sanghyeok Kim, Je-Ho Song, Sangyeon Woo, Youngjae Kim · 5 authors
Advances in blockchain technology have made a significant impact on a wide range of research areas due to the features such as transparency, decentralization and traceability. With the explosive growth of blockchain transactions, there has been a growing interest in improving the scalability of blockchain network. Sharding is one of the methods to solve this scalability problem by partitioning the network into several shards so that each shard can process the transactions in parallel. Ethereum places each transaction statically on a shard based on its account address without considering the complexity of the transaction or the load generated by the transaction. This causes the transaction load on each shard to be uneven, which makes the transaction throughput of the network decrease. In this paper, we propose a dynamic load balancing mechanism among Ethereum shards called D-GAS. The D-GAS dynamically balances the transaction load of each shard by relocating the accounts based on the gas consumption to maximize the transaction throughput. Ethereum gas is a unit that represents the amount of computational effort needed to execute operations in a transaction. Benchmarking results show that the D-GAS outperforms existing techniques by up to 12% in transaction throughput and decreases the makespan of transaction latency by about 74% under various conditions.
I. INTODUCTION Blockchain technology was first introduced as Bitcoin's underlying technology but soon later its extendable capabilities have been recognized. The peer-to-peer cryptocurrency, Bitcoin, is a core innovation in the financial sector nowadays. Its underlying technology, blockchain, is a type of a distributed ledger especially suitable for processing time ordered data. In addition, embedded cryptography functions of blockchain technology enable integrity of ledgers, authenticity of transactions, and privacy of transactions without a centralized control actor. Those make the blockchain different from traditional distributed database systems being used in the financial sector, e.g., it is practically impossible to modify or delete records of a ledger in the blockchain. This distributed and decentralized nature of the blockchain has attracteded financial institutions over the world to replace existing backbone technologies with blockchain technology. Blockchain keeps a record of all data exchanges -this record is referred to as a "ledger" in the cryptocurrency world, and each data exchange is a "transaction". Every verified transaction is added to the ledger as a "block" It utilizes a distributed system to verify each transaction -a peer-to-peer network of nodes. Once signed and verified, the new transaction is added to the blockchain and cannot be altered In the cryptocurrency world, your wallet address represents public key and your private key is what let's you authorize transfers, withdrawals, and other actions with your digital property like cryptocurrencies. As an aside, this is why it's so important to keep your private key safe -anyone who has your private key can use it to access any of your digital assets associated with your public key and do what they want with it! Each transaction in that ledger will have the same data: a digital signature, a public key, a timestamp, and a unique ID. For instance, the logistics sector considers blockchain technology for real-time visibility, improved efficiency, transparency, verifiability, and cost reduction for logistics. The property sector is adopting blockchain technology as well for digital but unforgeable property records, few disputes, transparency, verifiability, and lower transfer fees. The food sector is also investing blockchain technology to trace the movements of foods and tackle contamination faster.
In this paper, we discussed an efficient statistical method with proof-of-work consensus approach for cloud and fog computing. With this method, solution with precise probability in minimal time is realized. We have used the expectation maximization algorithm and polynomial matrix factorization. The advantages of this statistical method are the less iteration to converge to the consensus solution and easiness to configure the complete mathematical model as per the requirement. Moreover, the energy and memory consumption are also less which make this approach appealing for cloud and fog computing. The experimental results also show that the proposed approach is significantly efficient in terms of time and memory consumption. This novel approach seems beneficial for Internet-of-Things (IoT), one of the most fast-growing technologies in network computing.
We propose LazyLedger, a design for distributed ledgers where the blockchain\nis optimised for solely ordering and guaranteeing the availability of\ntransaction data. Responsibility for executing and validating transactions is\nshifted to only the clients that have an interest in specific transactions\nrelating to blockchain applications that they use. As the core function of the\nconsensus system of a distributed ledger is to order transactions and ensure\ntheir availability, consensus participants do not necessarily need to be\nconcerned with the contents of those transactions. This reduces the problem of\nblock verification to data availability verification, which can be achieved\nprobabilistically with sub-linear complexity, without downloading the whole\nblock. The amount of resources required to reach consensus can thus be\nminimised, as transaction validity rules can be decoupled from consensus rules.\nWe also implement and evaluate several example LazyLedger applications, and\nvalidate that the workload of clients of specific applications does not\nsignificantly increase when the workload of other applications that use the\nsame chain increase.\n
C Karthik, Madhavarapu Chandan, Abhinandan, Mohammad Rayan Baig
Blockchain Technology is an emerging technology in the software world. In order to understand the applications of the blockchain, it is necessary to understand how blockchain works. Blockchain was first introduced by Satoshi Nakamoto in 2008, which serve a Peer-to-Peer ledger for registering cryptocurrency bitcoin transactions. The blockchain is a list of records stored in the form of a chain. A blockchain is a decentralized distributed ledger which means a number of records are stored in a block and the block is added to the chain. Each block consists of a number of transactions for each transaction there will be a unique hash value, all hash values of the number of the transaction are combined and made a single hash value of the block and this follows Merkle root hash method. The invention of blockchain in cryptocurrency bitcoin solved the issue of double spending. The invention of blockchain in data backup can decrease the security complexity and duplication of the data. Rather than storing the data in one single hub that is the centralized system we can store the data in the blockchain which is a decentralized distributed ledger. In this decentralized system, the file is divided into a number of chunks stored into the blockchain which makes it difficult for data hacking and data tampering. In a centralized system if a server goes down then data is lost forever and in centralized system records can easily be altered because it does not have a backup to verify the records but in the blockchain, every peer in the network has the copy of the records and it is difficult to tamper the records. The files can be divided by a technology called Reed-Soloman erasure coding, generally used in CDs and DVDs. Reed-Soloman erasure coding allows dividing files in a redundant manner, where any 1 of 3 segments can fully recover a user's file.
As the blockchain technology grows, the scale of the network is becoming huger and huger, which brings us a troublesome question: how to allocate our data into each computer of a blockchain network? For example, we can store our data from one computer, until the memory space filled, and then switch to another, spending a lot of time searching in sole computer. Or we can only put a small amount of data into one computer, resulting in a huge network and plenty of transmission time. In this paper, we compute the cost of all the allocations according to the mathematical model. By studying the formula, we get the solution of balancing the search time and the space occupancy by users' input. Based on the result, we design a data allocation strategy that can decide how many data allocated to an individual computer.
Philipp Frauenthaler, Michael Borkowski, Stefan Schulte
The suitability of a particular blockchain for a given use case depends mainly on the blockchain's functional and non-functional properties. Such properties may vary over time, and thus, a selected blockchain may become unsuitable for a given use case. This uncertainty may hinder the widespread adoption of blockchain technologies in general. To mitigate the impact of volatile blockchain properties, we propose a framework that monitors several blockchains, allows the user to define functional and non-functional requirements, determines the most appropriate blockchain, and enables the switchover to that chain at runtime. Our evaluation using a reference implementation shows that switching to another blockchain can save cost and enable users to benefit from better performance and a higher level of trust.
The recent adoption of blockchain technologies and open permissionless networks suggest the importance of peer-to-peer atomic cross-chain transaction protocols. Users should be able to atomically exchange tokens and assets without depending on centralized intermediaries such as exchanges. Recent peer-to-peer atomic cross-chain swap protocols use hashlocks and timelocks to ensure that participants comply to the protocol. However, an expired timelock could lead to a violation of the all-or-nothing atomicity property. An honest participant who fails to execute a smart contract on time due to a crash failure, denial of service attacks or even network delays might end up losing assets. Although a crashed participant is the only participant who ends up worse off, current proposals are unsuitable for atomic cross-chain transactions in asynchronous environments where crash failures and network delays are the norm. In this paper, we present AC 3 WN, the first decentralized all-or-nothing atomic cross-chain commitment protocol. The redeem and refund events of the smart contracts that exchange assets are modeled as conflicting events. An open permissionless network of witnesses is used to guarantee that conflicting events could never simultaneously occur and either all smart contracts in an atomic cross-chain transaction are redeemed or all of them are refunded.
JCLedger is a BlockChain-based distributed ledger for JointCloud that can improve the reliability and convenience of cloud resource exchanges by empowering cooperation among multiple clouds. The biggest challenge for the implementation of JCLedger is the approach to consensus. The existing consensus algorithms for the public BlockChain, such as proof of work (PoW) or proof of stake (PoS) does not apply to the JointCloud, because they require a massive computing power with a low throughput or monopoly risk. In this paper, we propose a practical Byzantine-fault-tolerance (PBFT)-based consensus algorithm called proof of previous transactions (PoPT), in which the accountants are selected by a specific hash function from a certain number of candidates. The candidates are chosen according to the users' participation in JointCloud, and only candidates that join the PBFT-based consensus process instead of all users. We also propose a new BlockChain structure for parallel accounting to improve the scalability of JCLedger, and a consistent hashing algorithm is used to assign the transactions to different accountants. Simulation experiments show that the PoPT can shield the unequal computing power of the users to provide them equal accounting opportunities, and the parallel accounting can handle the massive and high-frequency transactions in JointCloud more efficiently.
Recentemente tem havido um interesse crescente na tecnologia de ledger distribuídos e aplicações de blockchain. Algoritmos tradicionais como PBFT e novos algoritmos como Proof of Work (PoW), Proof of Stake (PoS) e algoritmos híbridos foram desenvolvidos para lidar com a abertura desses sistemas. No entanto, estas Soluções não apresentam boa escalabilidade com o alto número de servidores ou dependem de uma criptomoeda subjacente. Estruturas hierárquicas como Steward ou Fireplug, apresentam melhor escalabilidade com um possível número de réplicas crescente, porém não lidam com o modelo competitivo esperado no ambiente blockchain. Neste artigo é proposta uma arquitetura hierárquica para lidar com o modelo competitivo do ambiente blockchain que também escala (horizontalmente) com o número de réplicas.
Blockchain technology is argued to have the potential to facilitate the development and improvement of cross-organizational business processes, on various aspects of the business process management discipline. In this paper, we review existing work on the use of blockchain technology to support business processes with a focus on cross-organizational settings. Based on this, we suggest to view blockchain as a software connector helping organizations to integrate the IT systems they use to support business processes. In addition, this paper suggests to use a model-driven engineering approach for the development of such connectors. By doing so, the need to develop a methodology helping to model and implement blockchain-based software connectors supporting cross-organizational business processes is highlighted. By adopting such an approach, organizations would be able to facilitate and speed up the development of blockchain-based solutions. This in turn would facilitate experimentations with this technology, which is considered as an important phase for organizations to derive value from it.
In Korea, a budget of tens of trillion won is put into the national R & D project every year [1]. Thanks to continuous technology and industrial development, Korea's ICT industry is gaining global attention. National R & D projects manage R & D projects in order of Planning - Evaluation - Management - Project results. In Korea, the R & D cycle process is diverse from the planning stage to the research results manager stage. In other words, we manage planning and evaluation by different departments and institutions. This type of management leads to problems such as redundant planning, insufficient sharing of research results, and duplicate submission. Currently, NTIS (National Technology Information Service) provides to address issues of redundancy and sharing. However, the NTIS's review of project redundancy is centered on keywords and does not provide information on the planning stage. This situation leads to redundant planning by ministries and closed management of research results. Therefore, we propose a platform that can easily share project planning information, review project redundancy, share research results, and check duplication of research results using block chain technology, which many experts and entrepreneurs refer to as future innovative technologies. In this paper, we propose a platform called Perfect Sharing Project Platform (PSPP). We describe that PSPP can achieve excellent research results through information sharing of project process. To support the perfect sharing, this platform uses a new notion of consensus algorithm, called POA (Proof of Atomicity). This platform is suitable for sharing information.
Robert Norvill, Mathis Steichen, Wazen M. Shbair, Radu State
Know Your Customer (KYC) processes performed by banks on their customers are redundant, cumbersome and costly. Therefore, a system is proposed to automate menial tasks and allow sharing of data related to KYC. A blockchain dictates the collaboration between different participants and several services are built around it to support the functionality of the system as a whole. An access control system is used to share data legitimately.
We propose a blockchain-based reseller system that ensures the ownership of the products, prevents multiple selling, and guarantees the transfer of the ownership. The system employs mutual collateral method to prevent any dishonest behavior by both seller and buyer. This system is built on Ethereum blockchain to maintain the public record of transactions and uses ERC-721 tokens to define the traded goods. Sellers must confirm their identity with a valid MetaMask account and pay a first-time registration fee. The smart contract utilizes the OpenZeppelin library's Ownable. sol contract to implement the transfer of ownership securely. Users interact with the blockchain through a web interface that holds a MySQL database. In this paper, we present the system architecture, database schemas, operating sequence, sample code segments, and testing methods with an example of event ticket reselling. This system can create a secure, transparent, and trusted reselling service.
Wazen M. Shbair, Mathis Steichen, Jérôme François, Radu State
Future blockchain applications are anticipated to serve millions of users. Thus the evaluation of new blockchain applications have to consider large-scale assessment of the technologies behind the scene. Most of current testing approaches have been done either on simulators or via local small blockchain networks. Hence, the performance in real world conditions is unpredictable. This demonstration introduces BlockZoom, a large-scale blockchain testbed that runs on top of a highly reconfigurable and controllable HPC platform. BlockZoom presents a reproducible environment for experimenting distributed ledgers technologies and smart contract applications. Through different configuration scenarios developers can evaluate the applications performance and the blockchain behavior at a scale comparable to the production environment. The target audience of this demonstration includes researchers and developers in blockchain technology.
William Pourmajidi, Lei Zhang, John Steinbacher, Tony Erwin · 5 authors
Logs contain critical information about the quality of the rendered services on the Cloud and can be used as digital evidence. Hence, we argue that the critical nature of logs calls for immutability and verification mechanism without the presence of a single trusted party. In this paper, we propose a blockchain-based log system, called Logchain, which can be integrated with existing private and public blockchains. To validate the mechanism, we create Logchain as a Service (LCaaS) by integrating it with Ethereum public blockchain network. We show that the solution is scalable (being able to process 100 log files per second) and fast (being able to "seal" a log file in 23 seconds, on average).
Sina Rafati Niya, Danijel Dordevic, Atif Ghulam Nabi, Tanbir Mann · 5 authors
Supply Chain Tracking (SCT) is considered as a major challenge for stakeholders of heterogeneous production, processing, transporting, storing, and selling systems. Studies on solutions in SCT reveal that many centralized SCT applications lack a design, which can support or even enable main features of a reliable, transparent, and publicly accessible SCT system for end users. This work demonstrates the implementation of a SCT application which, employs SC on the Ethereum blockchain (BC). This Decentralized Application (Dapp) provides a hardware-and platform-independent approach that flexibly enables multiple object combinations and transformations to be tracked with a use case-agnostic design and utilization.
Jelena Mišić, Vojislav B. Mišić, Xiaolin Chang, Saeideh G. Motlagh · 5 authors
In this work we provide comprehensive analytical model for Bitcoin distribution network. We apply Jackson network model on the whole Bitcoin network where individual nodes operate as priority M/G/1 queuing systems. Data arrival process to the nodes is modeled as a non-homogeneous Poisson process in which the data arrival rates to the nodes are derived from the analytical model of gossip data delivery protocol. This model considers random probability distribution of node connectivity. Performance results include network distribution time for blocks, node response time for blocks, and populations of data distribution algorithms as functions on network size. Usefulness of this model is demonstrated by efficiently computing the forking probability for the Bitcoin blockchain.
Pingcheng Ruan, Gang Chen, Tien Tuan Anh Dinh, Qian Lin · 6 authors
The success of Bitcoin and other cryptocurrencies bring enormous interest to blockchains. A blockchain system implements a tamper-evident ledger for recording transactions that modify some global states. The system captures entire evolution history of the states. The management of that history, also known as data provenance or lineage, has been studied extensively in database systems. However, querying data history in existing blockchains can only be done by replaying all transactions. This approach is applicable to large-scale, offline analysis, but is not suitable for online transaction processing. We present LineageChain , a fine-grained, secure and efficient provenance system for blockchains. LineageChain exposes provenance information to smart contracts via simple and elegant interfaces, thereby enabling a new class of blockchain applications whose execution logics depend on provenance information at runtime. LineageChain captures provenance during contract execution, and efficiently stores it in a Merkle tree. LineageChain provides a novel skip list index designed for supporting efficient provenance query processing. We have implemented LineageChain on top of Hyperledger and a blockchain-optimized storage system called ForkBase. Our extensive evaluation of LineageChain demonstrates its benefits to the new class of blockchain applications, its efficient query, and its small storage overhead.
In this paper, we address the performance analysis of Direct Acyclic Graph (DAG)-based cryptocurrency on the basis of its native structure. Several attempts on existing blockchain-based cryptocurrencies to resolve the limitation of the transaction processing rate has resulted in numerous form of solutions, such as side-chain, off-chain or data sharding. While those efforts are dedicated to overcome the limitation that the one-dimensional data structure has, a two-dimensional form of distributed ledger as known as DAG-based cryptocurrency has been emerged. Comparing with blockchain-based cryptocurrencies, DAG-based cryptocurrencies feature relatively faster issuance and confirmation of the transactions due to the individual processing method of the transactions. However, existing DAG-based cryptocurrencies also suffer from the instability of the performance, since the confirmation or validation delay can be varied by network condition such as transaction incoming rate. We derive the generic performance model of DAG-based cryptocurrency while varying the parameters. From the derived models, we propose some novel strategies to improve the performance of the DAG-based cryptocurrency system which encourages the participants of the cryptocurrency (both traders and nodes) to boost the transaction processing speed while keeping the ledger healthy. We show the effectiveness of our proposal by numerical statistics obtained by simulation, which results in maximum 46 percent of increase in our case.
Due to the fact that financial data stands a great risk of attack, several schemes are being deployed to ensure security and integrity of financial data. In considering the security of the financial transaction data, it is essential to consider a network that ensure that processing nodes would have copies of the financial accounting ledger so as to prevent complete when a section of the network fails. In this article we propose an application of a blockchain to financial transaction data backup mechanism over a decentralized network. By using a decentralized distributed blockchain ledger, each node can have a copy of the transaction data such that, failure in one node does not engender a total failure in transaction data. The system have been described and simulated using the element of account ledger which consist of credit and debit transaction accompanied by timestamps and transaction ID. To secure this information in the chain each block contains in addition to the account ledger information a hash of the previous block as well as the hash of the current block.
Blockchain is the latest technology developed in recent years for storing and sharing valuable information about transactions. This technology applies different methods for storing information that is unlike other existing traditional ways. Blockchain technology is an excellent example of maintainin