Aug 1, 2018·2018 17th IEEE International Conference On Trust, Security And Privacy In Computing And Communications/ 12th IEEE International Conference On Big Data Science And Engineering (TrustCom/BigDataSE)
Blockchain is the shared distributed ledger to record the history of transactions. In blockchain network, nodes validate the transactions and reach the consensus on the ordered transactions. The more transactions are happened, the more processing powers of nodes are needed. Shard is introduced to blockchain for processing the multiple transactions in parallel. In this paper, we propose the blockchain for a domain based static sharding. We split a blockchain into multiple shards based on the domain. In each shard, nodes validate the multiple transactions concurrently and keep the shard's ledger separately. With this, it can be processing of low-latency transaction. Also, by changing the composition of committee members that validate blocks dynamically, we can enable the blockchain to be more trust.
Aug 1, 2018·2018 2nd International Conference on I-SMAC (IoT in Social, Mobile, Analytics and Cloud) (I-SMAC)I-SMAC (IoT in Social, Mobile, Analytics and Cloud) (I-SMAC), 2018 2nd International Conference on
When Bitcoin's price skyrocketed then cryptocurrencies dragged the world's attention. Since then "Cryptocurrency Mining" has became a buzz word for computer geeks as well as for those who wanted to add a new source of income. "Mining" is a process of solving computational problems using hardware which results in obtaining rewards in the form digital currency. Large number of people who could afford a personal computer, started getting attracted towards mining, which resulted in formation of "Mining Pools". Mining Pools are an explicit example of teamwork where miners share their efforts to mine cryptocurrencies. This paper throws light on some of the key concepts of mining such as hash rates, pool analytics and various mining software. A complete financial report is enclosed in this paper which discusses the profitability or non-profitability of various cryptocurrencies and hardware by considering various attributes like pool fee, electricity costs, and revenues excluding the cost of hardware. This paper is an outcome of practical mining of several cryptocurrencies on GPUs and CPUs (non-custom hardware) which results in contextually slower mining as compared to high-end miners. Proposed data will guide novice miners to start mining.
Bitcoin is a decentralized crypto-currency, which is based on the peer-to-peer network, and was introduced by Satoshi Nakamoto in 2008. Bitcoin transactions are written by using a scripting language. The hash value of a transaction’s script is used to identify the transaction over the network. In February 2014, a Bitcoin exchange company, Mt. Gox, claimed that they had lost hundreds of millions US dollars worth of Bitcoins in an attack known as transaction malleability. Although known about since 2011, this was the first known attack that resulted in a company loosing multi-millions of US dollars in Bitcoins. Our reason for writing this paper is to understand Bitcoin transaction malleability and to propose an efficient solution. Our solution is a softfork (i.e., it can be gradually implemented). Towards the end of the paper we present a detailed analysis of our scheme with respect to various transaction malleability-based attack scenarios to show that our simple solution can prevent future incidents involving transaction malleability from occurring. We compare our scheme with existing approaches and present an analysis regarding the computational cost and storage requirements of our proposed solution, which shows the feasibility of our proposed scheme.
As an emerging decentralized architecture and distributed computing paradigm underlying Bitcoin and other cryptocurrencies, blockchain has attracted intensive attention in both research and applications in recent years. The key advantage of this technology lies in the fact that it enables the establishment of secured, trusted, and decentralized autonomous ecosystems for various scenarios, especially for better usage of the legacy devices, infrastructure, and resources. In this paper, we presented a systematic investigation of blockchain and cryptocurrencies. Related fundamental rationales, technical advantages, existing and potential ecosystems of Bitcoin and other cryptocurrencies are discussed, and a six-layer reference model of the blockchain framework is proposed with detailed description for each of its six layers. Potential applications of blockchain and cryptocurrencies are also addressed. Our aim here is to provide guidance and reference for future research along this promising and important direction.
The Distributed nature of Bitcoin introduces security issues that necessitate security-specific enhancements in Bitcoin protocol. Therefore, proposing a method of incorporating criteria check and verification process for miners to participate in the mining process and join the mining pool respective
Blockchain platforms, such as Ethereum, allow a set of actors to maintain a\nledger of transactions without relying on a central authority and to deploy\nscripts, called smart contracts, that are executed whenever certain\ntransactions occur. These features can be used as basic building blocks for\nexecuting collaborative business processes between mutually untrusting parties.\nHowever, implementing business processes using the low-level primitives\nprovided by blockchain platforms is cumbersome and error-prone. In contrast,\nestablished business process management systems, such as those based on the\nstandard Business Process Model and Notation (BPMN), provide convenient\nabstractions for rapid development of process-oriented applications. This\narticle demonstrates how to combine the advantages of a business process\nmanagement system with those of a blockchain platform. The article introduces a\nblockchain-based BPMN execution engine, namely Caterpillar. Like any BPMN\nexecution engine, Caterpillar supports the creation of instances of a process\nmodel and allows users to monitor the state of process instances and to execute\ntasks thereof. The specificity of Caterpillar is that the state of each process\ninstance is maintained on the (Ethereum) blockchain and the workflow routing is\nperformed by smart contracts generated by a BPMN-to-Solidity compiler. The\nCaterpillar compiler supports a large array of BPMN constructs, including\nsubprocesses, multi-instances activities and event handlers. The paper\ndescribes the architecture of Caterpillar, and the interfaces it provides to\nsupport the monitoring of process instances, the allocation and execution of\nwork items, and the execution of service tasks.\n
Blockchain is an emerging technology that enables new forms of decentralized software architectures, where distributed components can reach agreements on shared system states without trusting a central integration point. Blockchain provides a shared infrastructure to execute programs, called smart contracts, and to store data. Since blockchain technologies are at an early stage, there is a lack of a systematic and holistic view on designing software systems that use blockchain. We view blockchain as part of a bigger system, which requires patterns for using blockchain in the design of their software architecture. In this paper, we collect a list of patterns for blockchain-based applications. The pattern collection is categorized into four types, including interaction with external world patterns, data management patterns, security patterns and contract structural patterns. Some patterns are designed considering the nature of blockchain and how it can be specifically introduced within real-world applications. Others are variants of existing design patterns applied in the context of blockchain-based applications and smart contracts.
Jun Duan, Alexei Karve, Vugranam C. Sreedhar, Sai Zeng
Business interest in blockchain technology is increasing due the potential for change that it offers. Large scale adoption in enterprise IT environments brings about a need for service management and DevOps processes for blockchain deployments. Nodes in the network may fail or be taken down for maintenance requiring visibility across hybrid, traditional, cloud enabled and cloud native deployments. Service management is necessary to ease deployment woes for those looking to install code within their own data centers on-premises or on dedicated cloud servers and further to handle the life cycle of the deployments that includes security patches, critical updates, upgrades, change management and restarting services. In this paper, we provide a mechanism to optimally perform such operations with no disruption to the consensus and transactions for such emerging blockchain applications.
Today, Cloud services are mainly traded on provider platforms such as on Amazon's EC2 On-Demand marketspace. Thereby, consumers and providers neither negotiate the price nor the characteristics of the services. The recent years underpin a trend to more dynamic Cloud markets. So e.g. the Cloud provider Virtustream released a revenue model where consumers are charged based on consumed μVMs while Amazon extended it's spot market with spot blocks and spot fleet management. Hence, multi-round bilateral negotiations are a promising approach for trading Cloud services on future Cloud markets. Such negotiations are based on an alternating exchange of offers and hence, they are termed Bazaar-negotiations. Specifications such as the WS-Agreement Negotiation - which is maintained by the Open Grid Forum - foster the development of Bazaar-based markets. To ensure integrity and transparency of negotiations with untrusted negotiation partners - which is a precondition for the adaption of Bazaar-based Cloud markets - blockchains are a promising approach. In this paper we introduce a concept of a blockchain for Bazaar-negotiations whereby we assume that the offers exchanged during negotiations follow the structure defined in the WS-Agreement Negotiation specification. We implemented it within a CloudSim based simulation environment which is able to simulate such Bazaar-based markets to show its technical feasibility.
Jul 1, 2018·2018 IEEE International Conference on Internet of Things (iThings) and IEEE Green Computing and Communications (GreenCom) and IEEE Cyber, Physical and Social Computing (CPSCom) and IEEE Smart Data (SmartData)
Saulo dos Santos, Daniyal Khowaja, Muskan Vinayak, Ruppa K. Thulasiram · 5 authors
Cryptocurrencies especially bitcoin has received a lot of attention in the past year. The popularity has increased the volume of transactions in an unprecedented way. The time to complete a simple pairwise transaction from one virtual wallet to other takes time in proof-of-work where transactions are added into the Blockchain. At the same time, validating a pairwise transaction is very significant in this new technology as a payment option. Through this study, we propose a heuristic approach for validating pairwise transactions on cryptocurrencies. Our heuristic simulate all entities sending and receiving transactions among themselves. We use SHA256 algorithm to enhance our solution for pairwise transactions, creating a local Blockchain of transactions that has been used in the development of various Blockchain systems. For our experiments, we ran simulations in-file and in-memory with 2 million transactions in 290.39 and 5.34 seconds respectively. Our peak transactions per second was 6.887 using a file persistence version and 374.255 with in-memory version. Based on our experiments we conclude that is possible to improve the number of transactions processed per second increasing the size of the block as well as avoiding access to the file during the simulation. We also present some of our results implementing our algorithm in a parallel environment and hence show better performance.
Information and communication technology has been a positive dynamic force behind improving performance. Simultaneously enabling digital business ecosystems to become an increasingly popular concept for modelling and building distributed systems in heterogeneous, decentralized and open environments. These business solutions have created an opportunity for automated business relations and transactions as well as implementing blockchain based performance measurement systems (PMS), allowing PMS to be more advanced giving validation and verification of received data hence the indicators. This paper evaluates feasibility of blockchain based PMS for logistics industry. Today the performance of supply chain stakeholders including transport logistics is lacking transparency and restraining innovative digital improvements towards a connected, smart and efficient ecosystem. Current public blockchains are not feasible for given use case due to limited throughput, and transaction cost. In this paper we have evaluated different technological alternatives and found several new developments that make blockchain technology suitable for ensuring logistics sector performance measurement integrity. Validated indicators can add trustworthiness and visibility to management and process improvement decisions, as well as be subject to smart contracts and monetary transactions.
Blockchain technology is the underlying infrastructure and support technology to build trust of Bitcoin. It is not only an emerging technology that relies on pure mathematical method to create trust relationship in a distributed environment but also an innovative combination of hash algorithm, asymmetric cryptography, time stamp, consensus mechanism and many other technologies, with characteristics of decentralization, trustlessness, collective maintenance, reliable database, openness, security and untamperability, anonymity, verifiability and traceability, programmable and so on. This paper mainly introduces the technical characteristics and models of block chain, summarizes the development status and branch classification of Blockchain and outlines the future application of Blockchain technology.
Jul 1, 2018·2018 IEEE International Conference on Internet of Things (iThings) and IEEE Green Computing and Communications (GreenCom) and IEEE Cyber, Physical and Social Computing (CPSCom) and IEEE Smart Data (SmartData)
In Bitcoin, it is well known that the confirmation of a transaction issued by a user takes a longer time than the mean block-generation time of 10 minutes. In order to understand the stochastic behavior of the transaction-confirmation process, we consider a queueing model with batch service and general input. In our queueing model, we assume that the transaction interarrival times are independent and identically distributed (i.i.d.), and follow a general distribution, and that the transactions waiting in the queue are served in a batch manner. We define the number of transactions in queue just before a transaction arrival as the system state, deriving the steady-state distribution and the mean transaction-confirmation time by matrix analytic method. In numerical examples, we compare analytical results with trace-driven simulation, discussing the applicability of our queueing model to the prediction of the transaction-confirmation time. It is found that exponential-type distributions such as exponential distribution and hyper-exponential one can accurately estimate the mean transaction-confirmation time for the current maximum block-size limit of 1 Mbyte.
Next-generation blockchain ecosystem will be fuelled by a large variety of blockchain systems. These systems increasingly demand proper cross-chain cooperation to provide richer functionalities and enhanced capabilities in the future landscape. How to enable such `interoperability' - effective communication and efficient data transfer across multiple blockchain systems is thus critical and facing many unprecedented theoretical and practical challenges. In this paper, we first clarify the definition of interoperability based on the cross disciplinary nature. Second, a roadmap of challenges needed to be addressed for interoperability has been laid out. Third, we articulate novel architectural approaches to fill in the gap by enforcing the interoperability from different blockchain layers.
Jul 1, 2018·2018 IEEE International Conference on Internet of Things (iThings) and IEEE Green Computing and Communications (GreenCom) and IEEE Cyber, Physical and Social Computing (CPSCom) and IEEE Smart Data (SmartData)
Kwame-Lante Wright, Martin Martinez, Uday Chadha, Bhaskar Krishnamachari
Edge computing has emerged as an effective offloading strategy for constrained devices. It enables low-capability devices to leverage nearby resources for assistance with computationally-intensive tasks. We envision a future where Internet of Things (IoT) devices may autonomously transact with other more powerful devices to request such offloading services. We believe blockchain-based technologies can help facilitate this process by tracking usage and managing payments. In this work we introduce SmartEdge, an Ethereum-based smart contract for edge computing and show that it is a low-cost, low-overhead tool for compute-resource management.
We propose a decentralized routing algorithm that can be implemented in Bitcoin Lightning Network. All nodes in the network contribute equally to path searching. The algorithm is inspired from ant path searching algorithms.
This thesis focuses on the integration of smart contracts into the Bazo Blockchain with the goal of creating a platform for decentralized applications. Smart contracts are programs that are stored on a blockchain and can be triggered by transactions. Smart contracts offer opportunities in automation and bring along advantages provided by blockchains such as immutability, public visibility of transactions and decentralization. As blockchains are trust-less protocols, it is guar- anteed that smart contracts are executed as intended. The integration of smart contracts was solved by implementing a virtual machine that executes the instructions sent by a transaction. This stack based virtual machine uses byte arrays as base type, which enables the virtual machine to deal with numbers of arbitrary length. Working with elements of arbitrary size requires taking the length of the elements into account, when calculating the gas cost, in addition to the base cost of the instruction type. Furthermore, the virtual machine was embedded within the mining application, which required to alter the blockchain protocol and the mining application. As a result, smart contracts can be deployed and transactions that call functions of smart contracts can be executed. Calling a smart contract function leads to the execution of the contract in the virtual machine and persisting the result in the blockchain. The Bazo Blockchain contin- ues to be a research project, this means it’s not ready for production use due to complex setup and handling. Follow-up theses could simplify the development of smart contracts for the Bazo Blockchain by creating a high-level programming language that can be compiled to Bazo virtual machine instructions.
Message digest algorithms are one of the underlying building blocks of\nblockchain platforms such as Ethereum. This paper analyses situations in which\nthe message digest collision resistance property can be exploited by attackers.\nTwo mitigations for possible attacks are described: longer message digest sizes\nmake attacks more difficult; and, including timeliness properties limits the\namount of time an attacker has to determine a hash collision.\n
Blockchains and distributed ledgers, the technologies underlying Bitcoin and other decentralized transaction systems, have been garnering increasing interest in the theoretical distributed comput- ing community. The current column, by Antonio Fernández Anta, Chryssis Georgiou, Kishori Konwar, and Nicolas Nicolaou, starts with an informative overview of the world of distributed ledgers and motivates the need for rigorous approaches. The authors present an approach for formally specifying a distributed ledger in the context of several popular consistency conditions. The authors then give algorithms that implement the di erent variants in message-passing systems subject to crash failures. The article closes with a discussion of intriguing open questions. Many thanks to Antonio, Chryssis, Kishori and Nicolas for their timely contribution!
Hashgraph is data structure and consensus algorithm that is fast, with a very high throughput and low consensus latency, secure because of the asynchronous byzantine fault tolerant and fair due to the fairness of access, ordering, and timestamps. These properties enable new decentralized applications such as a stock market, improved collaborative applications, games, and auctions. Hashgraph is a new consensus protocol that has garnered attention lately by being projected as a technology that will make blockchains obsolete. Hashgraph currently scales only in the number of transactions processed but does not scale with the number of nodes in the network. Hashgraph will face the same issues that other public blockchains are facing today and may not be able to maintain its security and performance. In fact, scalability is still an open problem for public blockchains.
David Vangulick, Bertrand Cornélusse, Damien Ernst
Energy communities and peer-to-peer energy exchangesare expected to play an important role in the energy transition. In this context, the blockchain approach can be employed to foster this decentralized energy market. In [1],we evaluated several designs that should allow a Distribution System Operator (DSO) to accept peer-to-peer energyexchanges supported by this technology. This acceptanceis based on criteria such as a strong link with the wholesale/retail market, the resilience of the consensus to approve a block, the accuracy, traceability, privacy and security of the proposed schemes. We concluded that proof-ofstake (PoS), where the choice of node that creates a block isbased on a measure of its wealth, is the only method to fulfill these requirements. In the present paper, we clarify theidentification and estimation of bidding models to ensurethat the PoS that we are developing is a correct responseto two major issues with the PoS methodology, namely theconcentration of wealth and the ”nothing to stake” issue.1
Carlos Melo, Jamilson Dantas, Danilo Oliveira, Iure Fé · 8 authors
The blockchain shared ledger emerged as an alternative to the bureaucratic banking system that may take days to confirm a payment or a transfer between clients. The blockchain concept evolved and became viable for various applications beyond the domain of financial transactions. Blockchains become a way to reach better relationships through contract validation, documents transfer, and personal and business data security. Recently, the blockchain-as-a-service has debuted on Microsoft Data Centers, and now many share an infrastructure that can change and improve their security routines. This paper evaluates the feasibility of a blockchain-as-a-service infrastructure and helps those who plan to deploy or sell blockchains. A modeling methodology based on Dynamical Reliability Block Diagrams (DRBD) is adopted to evaluate two dependability attributes: system's reliability and availability. The proposed infrastructure contains the minimum requirements to deploy the Hyperledger Cello, a platform to create and manage blockchains. The availability results pointed out a system downtime of 121 hours per year and reliability issues that must be addressed when building blockchain-as-a-service infrastructures.