Education plays an important role in the economic and social progress of any community. Currently, the higher education system needs immense of enhancements for fulfilling essential needs of the productive and beneficial educational environment. The major challenges faced by the higher education system is the verification of student's data at the time of admission in the university. Current admission system requires a lot of time along with an excess of human resources. there is no mechanism for the authentication of degrees and educational certificates in Pakistan. In this paper, the proposed system based on blockchain technology. This system can validate and verify degree/certificates. The proposed system can verify and validate the student's educational record from respective educational stakeholders like HEC, PEC, IBCC. It allows students to apply for admission using the single platform at a few clicks. Using blockchain, this system is secure, tamper-resistant, time saving, efficient and reliable.
There has been a great focus on services across the Internet. Freelancing is one such service that is thought to be in the middle of a dramatic change. Here, the online freelancing platforms have created global opportunities for people to outsource their works, and seek employment slots, like a job. Online freelancing platforms have transformed how, when, and where the work is to be performed. However, these platforms also carry risks. These platforms lack credibility, security, and flexibility d ue to centralized nature. Designing n ew approach, that overcomes these issues, is very important for growth of freelancing. This paper proposes Boomerang, a decentralized freelance administration paradigm on Hyperledger Fabric. Hyperledger Fabric is a distributed operating system for permissioned blockchains. The Boomerang integrates blockchain-based distributed ledger, consensus protocol, and a fine-grained access control. The design includes demonstration of Boomerang and a detailed description of Boomerang architecture. The prototype implementation, based on the Boomerang architecture, is detailed next. The implementation of database and application logic are illustrated for better understanding. In addition, the tools chosen and assumptions made in prototype development are mentioned. This research would help the coming and existing startups to secure grow fast with requisite security.
One of the current challenges that faces individual organizations that are attempting to utilize blockchain in making more secure and transparent transaction between organizations are standards. Not all platforms, however, are suitable. In this paper, we provide a comparison of blockchain development platforms for developers to choose the best platform based on their need.
Bitcoin is a cryptocurrency which acts as an application protocol that works on top of the IP protocol. This paper focuses on distinct Bitcoin security features, including security services, mechanisms, and algorithms. Further, we propose a well-defined security functional architecture to minimize security risks. The security features and requirements of Bitcoin have been structured in layers.
Summary This paper reviews some recent blockchain‐based applications for information capture, distribution and preservation. As part of that review, this paper examines two key concerns with current blockchain designs for accounting and supply chain transactions: data independence and multiple semantic models for the same information distribution problem. Blockchain applications typically integrate database, application and presentation tiers all in the same ledger. This results in a general inability to query information in the ledger and other concerns. Further, since most applications appear to be private blockchain applications, there is a concern of agents needing to accommodate multiple blockchains depending on who their trading partners are and what they request. Finally, this paper uses a distributed database to design a ‘blockchain‐like’ system for virtual organizations.
With the rapid development of blockchain platforms, it is important that different implementations are tested and analyzed for comparative purposes. One such implementation is Hyperledger Sawtooth, a new member of the Hyperledger family. Sawtooth blockchain is a permissioned implementation developed in part by Intel. While research has been done on Hyperledger Fabric, research on Sawtooth is not well documented. Using the Hyperledger Caliper benchmarking tool, we aim to test the performance of the blockchain and identify potential issues.
Lan N. Nguyen, Truc Nguyen, Thang N. Dinh, My T. Thai
A major challenge in blockchain sharding protocols is that more than 95% transactions are cross-shard. Not only those cross-shard transactions degrade the system throughput but also double the confirmation time, and exhaust an already scarce network bandwidth. Are cross-shard transactions imminent for sharding schemes? In this paper, we propose a new sharding paradigm, called OptChain, in which cross-shard transactions are minimized, resulting in almost twice faster confirmation time and throughput. By treating transactions as a stream of nodes in an online graph, OptChain utilizes a lightweight and on-the-fly transaction placement method to group both related and soon-related transactions into the same shards. At the same time, OptChain maintains a temporal balance among shards to guarantee the high parallelism. Our comprehensive and large-scale simulation using Oversim P2P library confirms a significant boost in performance with up to 10 folds reduction in cross-shard transactions, more than twice reduction in confirmation time, and 50% increase in throughput. When combined with Omniledger sharding protocol, OptChain delivers a 6000 transactions per second throughput with 10.5s confirmation time.
Murat Kuzlu, Manisa Pipattanasomporn, Levent Gurses, Saifur Rahman
Focusing on one of the most popular open source blockchain frameworks-Hyperledger Fabric, this paper evaluates the impact of network workload on performance of a blockchain platform. In particular, the performance of the Hyperledger Fabric platform is evaluated in terms of: (a) throughput, i.e., successful transactions per second; (b) latency, i.e., response time per transaction in seconds; and (c) scalability, i.e., number of participants serviceable by the platform. The results indicate that the instance of Hyperledger Fabric platform being implemented can support up to 100,000 participants on the selected AWS EC2 instance. As long as the transaction rate is maintained within 200 transactions per seconds, the network latency is in the order of fraction of a second.
Amjad Aldweesh, Maher Alharby, Maryam Mehrnezhad, Aad van Moorsel
Ethereum and other blockchains rely on miners contributing computational power to execute tasks such as the proof of work consensus mechanism and the execution and validation of smart contracts. Miners receive a fee, and for the correct operation of the blockchain, rewards should be proportional to the required investment (equipment, energy use, etc.). In Ethereum, the reward obtained for executing smart contracts is set statically, associating a fee with each operation code (opcode) in the smart contract. To determine whether fees are aligned with investments made, we propose OpBench, a platform-independent benchmarking approach. OpBench measures the CPU time required to execute opcodes in the Ethereum Virtual Machine. We implemented OpBench for the PyEthApp and Go-Ethereum clients, and present results for both platforms on three different machines and operating systems. The results show that the static fees set by Ethereum are not always proportional to the invested CPU time, with up to an order of magnitude difference across opcodes. The results also show a markable difference in performance between clients, with the Go client outperforming the Python client across machines.
Ethereum is the largest blockchain platform supporting smart contracts with the second biggest market capitalization. Ethereum data can yield many useful insights because of the large volume of transactions, accounts and blocks as well as the popular applications developed as smart contracts. Studying Ethereum data can also reveal many new attacks to the platform and its smart contracts. Unfortunately, it is non-trivial to systematically explore Ethereum because it involves massive heterogeneous data, which are produced and stored in different ways. Although a few recent studies report some interesting observations about Ethereum, they are limited by their data acquisition methods which cannot provide comprehensive and precise data. In this paper, to fill the gap, we propose DataEther, a systematic and high-fidelity data exploration framework for Ethereum by exploiting its internal mechanisms. Besides supporting the analyses in existing studies, DataEther further empowers users to explore unknown phenomena and obtain in-depth understandings. We first describe how we tackle the challenging issues in developing DataEther, and then use four data-centric applications to demonstrate its usage and report many new observations.
Zhongli Dong, Emma Zheng, Young Choon, Albert Y. Zomaya
Directed Acyclic Graph (DAG) has been emerging as the so-called Blockchain 3.0 after Bitcoin (Blockchain 1.0) and Ethereum (Blockchain 2.0). This new distributed ledger technology is getting significant attention for its high performance and low transaction fee. There have already been several notable implementations, such as IOTA [1], Nano [2] and Byteball [3]. In this paper, we present DAGBENCH as a performance evaluation framework for DAG implementations. DAGBENCH provides a number of sample workloads and adaptors that make effective and easy evaluation of different DAG implementations. It allows any DAG implementation to be evaluated by adding an adaptor. DAGBENCH allows to measure the performance of DAG implementation in terms of throughput, latency, scalability, success indicator, resource consumption, transaction data size and transaction fee. We demonstrate the efficacy of DAGBENCH with different DAG implementations. In particular, we have conducted experiments, on Amazon EC2, with three popular DAG implementations: IOTA, Nano and Byteball. Our experimental results provide the performance comparison between these implementations that helps developers/users effectively evaluate different performance characteristics; and, this enables them to identify bottlenecks and accordingly to improve performance.
Muhammad El-Hindi, Martin Heyden, Carsten Binnig, Ravi Ramamurthy · 6 authors
In this demo we present BlockchainDB, which leverages blockchains as storage layer and introduces a database layer on top that extends blockchains by classical data management techniques (e.g., sharding). Further, BlockchainDB provides a standardized key/value-based query interface to facilitate the adoption of blockchains for data sharing use cases. With BlockchainDB we can thus not only improve the performance and scalability of blockchains for data sharing but also decrease the complexity for organizations intending to use blockchains for this use case.
Ankur Sharma, Felix Schuhknecht, Divya Agrawal, Jens Dittrich
Within the last few years, a countless number of blockchain systems have emerged on the market, each one claiming to revolutionize the way of distributed transaction processing in one way or the other. Many blockchain features, such as byzantine fault tolerance, are indeed valuable additions in modern environments. However, despite all the hype around the technology, many of the challenges that blockchain systems have to face are fundamental transaction management problems. These are largely shared with traditional database systems, which have been around for decades already. These similarities become especially visible for systems, that blur the lines between blockchain systems and classical database systems. A great example of this is Hyperledger Fabric, an open-source permissioned blockchain system under development by IBM. By implementing parallel transaction processing, Fabric's workflow is highly motivated by optimistic concurrency control mechanisms in classical database systems. This raises two questions: (1)~Which conceptual similarities and differences do actually exist between a system such as Fabric and a classical distributed database system? (2)~Is it possible to improve on the performance of Fabric by transitioning technology from the database world to blockchains and thus blurring the lines between these two types of systems even further? To tackle these questions, we first explore Fabric from the perspective of database research, where we observe weaknesses in the transaction pipeline. We then solve these issues by transitioning well-understood database concepts to Fabric, namely transaction reordering as well as early transaction abort. Our experimental evaluation under the Smallbank benchmark as well as under a custom workload shows that our improved version Fabric++ significantly increases the throughput of successful transactions over the vanilla version by up to a factor of 12x, while decreasing the average latency to almost half.
Min Choi, Rupali Shinde, Sechang Oh, Oh‐Young Kwon
In this paper, we present a badge awarding system for performance assessment in education using blockchain technology. Learners will be awarded badges, which are certified for a predetermined level of progress in terms of learning. All the badges are stored in a backpack, which is an environment for storing and presenting the obtained badges. Badges are immutable and verifiable as well as rigid. The use of badges in the education system makes education more interesting, skill-based, and adaptable to changes. The key contribution of our work is in terms of compatibility with Openbadge specification and integrated cooperating platform between digital badge awarding and blockchaining. Our system implementation is compatible with Open Badges of IMS Global Learning Consortium, which is used to earn, issue, and award badges across various platforms. The badges are trusted by the IMS standard, the criteria to earn a badge is verified through the network, and the overall process is transparent compared to the traditional education system. Moreover, all badge awarding events in our system are recorded in a blockchain. Once stored, the contents cannot be tampered with. Thereafter, anyone can check the validity of the badge through the blockchain. Our platform will be useful for distance learning as well as time and location independent learning. The experimental results are as follows. On a Bitcoin-based digital badge publishing platform, the execution time required to award the badge is 24.53 s, while on the Ethereum-based digital badge publishing platform, the execution time to award the badge is only 3.86 s. It can also be used for career management and personal history. The learners can obtain the current knowledge required for a job. Lifelong learning will be also possible with this platform.
Swagatika Sahoo, Akshay M. Fajge, Raju Halder, Agostino Cortesi
In the nine years since its launch, amid intense research, scalability is always a serious concern in blockchain, especially in case of large-scale network generating huge number of transaction-records. In this paper, we propose a hierarchical blockchain model characterized by: (1) each level maintains multiple local blockchain networks, (2) each local blockchain records local transactional activities, and (3) partial views (tunable w.r.t. precision) of different subsets of local blockchain-records are maintained in the blockchains at next level of the hierarchy. To meet this objective, we apply abstractions on a set of transaction-records in a regular time interval by following the Abstract Interpretation framework, which provides a tunable precision in various abstract domain and guarantees the soundness of the system. While this model suitably fits to the real-worlds organizational structures, the proposal is powerful enough to scale when large number of nodes participate in a network resulting into an enormous growth of the network-size and the number of transaction-records. We discuss experimental results on a small-scale network with three sub networks at lower-level and by abstracting the transaction-records in the abstract domain of intervals. The results are encouraging and clearly indicate the effectiveness of this approach to control exponential growth of blockchain size w.r.t. the total number of participants in the network.
With the rapid evolution of technological, economic, and regulatory landscapes, contemporary blockchain platforms are all but certain to undergo major changes. Therefore, the applications that rely on them will eventually need to migrate from one blockchain instance to another to remain competitive and secure, as well as to enhance the business process, performance, cost efficiency, privacy, and regulatory compliance. However, the differences in data and smart contract representations, modes of hosting, transaction fees, as well as the need to preserve consistency, immutability, and data provenance introduce unique challenges over database migration. We first present a set of blockchain migration scenarios and data fidelity levels using an illustrative example. We then present a set of migration patterns to address those scenarios and the above data management challenges. Finally, we demonstrate how the effort, cost, and risk of migration could be minimized by choosing a suitable set of data migration patterns, data fidelity level, and proactive system design. Practical considerations and research challenges are also highlighted.
In order to meet the increasing demand of the blockchain, it needs to find a solution to the scalability problem. It has been focused on sharding recently to address the scalability problem. In the sharding method, the blockchain is divided into pieces. Instead of a more extensive network, networks with fewer nodes are created. As a result, it becomes more important that each node in the network is reliable. In this study, studies using sharding method have been investigated, and methods for the assigning nodes to shards are proposed. The use of learning-based adaptive methods for this process will contribute to the safe and reliable use of shards. The probability of the shards to deteriorate and influence the whole blockchain will be reduced.
This paper proposes a double-blockchain structured trading scheme (DBR-ETS) in carbon emission permits secondary market and introduces the enterprises' reputation, which is used to urge enterprises to actively invest in carbon emission reduction, and ultimately achieve carbon emission reduction in the overall society. The application of blockchain technology guarantees the security and privacy of distributed system. The confirmation chain and financial chain in the double-blockchain structure divide the transaction into two relatively independent processes, which can not only alleviate the transaction redundancy in the system but also improve the security of the system through the mutual verification of the two chains. The reputation-based transaction fee mechanism allows enterprises to promote their reputation by increasing investment in emission reduction. In the case study, we verified the superiority of the double-blockchain structure and the effect of the transaction fee mechanism on emission reduction.
Blockchain technologies have grown swiftly in recent years, primarily due to the advent of Bitcoin. Blockchain is a consensus of data structures or blocks programmed for cryptographically storing organized data, which is spread across nodes, so that various operations can be executed on it. Originally blockchain was designed for storing digital coins as system states and now has grown beyond crypto-currencies to support user-defined decentralized autonomous applications or smart contracts with Ethereum. Growing interest from the industry and wide range of applications has triggered development of new blockchain platforms. As the technology is progressing quickly, it is necessary and challenging to have a more profound perspective of what the core technology platforms have to provide in order to establish which blockchain implementation should be leveraged for a particular application. We therefore grasp the key aspects of blockchain and compare how the current blockchain implementations are different from each other, both qualitatively and quantitatively in terms of design architecture, codebase, consensus algorithms and performance. Drawing from the comparison we identify the current challenges as well as performance issues in blockchain adoption, thus suggesting possible solutions and future implementations to improve performance of blockchain and provide subsequent research directions.
Abhilash Kancharla, Jongho Seol, Nicole Park, Indy Park · 5 authors
This paper presents a work on how to assure the dependability of a crypto system built across on and off the blockchain by using the proposed adaptive checkpoint and rollback algorithm, and a prototype is developed for demonstration purpose.The theoretical background of the proposed checkpoint and rollback algorithm is studied to characterize the variables affecting the dependability such as security, authenticity and reliability with respect to the rates of hit by any events of those issues, the rates to detect and diagnose, and then the rate to vote for a consensus whether to trigger a rollback or not. Based on the variables characterization in a stochastic manner, then steady state probabilities and state transition probabilities are derived in order to assure the ultimate effective dependability of each individual dependability variable (i.e., security, authenticity and reliability), then finally to assure the dependability in a compound manner with each variable assigned a weight depending on the nature of the systems specifications.Based on the theoretical study, a protype of a crypto system is built to demonstrated the underlying architecture and operations and to justify the need for such system to take synergistic advantages from both on- and off-chain blockchains, with an experimental result of a benefit in gas fee which is the most exigently addressed issue today in blockchain systems especially in Ethereum network of blockchains. An astonishing gas fee saving results are demonstrated. It is observed that the crypto system benefits more if more computationally intensive transactions are executed off-chain while vice versa.
Unspent Transaction Output (UTXO) set is the foundational model used in many blockchain systems to represent assets. The benefits of UTXO representation include parallel processing, privacy, etc. However, the increasing size of UTXO set is degrading the access performance and severely brings down the validation speed of blockchain further, especially in resource-constrained scenerios, such as IoT. In this paper, we present a memory-economical storage system for UTXO-based blockchain. Based on the inherent properties of UTXO set, we propose two lossless compression techniques to reduce the memory space occupied by UTXO set. Besides, the database related operations are adopted to make the proposed mechanism easily applied in current blockchain system. Taking Bitcoin as the object of study, our mechanism can deliver 2.9-4.5x memory reduction and orders of magnitude validation speed improvement in resource-constrained situations. This compact system will improve validation performance and extend applied scope of blockchains.
With ever more IoT (Internet of Things) and bigdata applications, the emerging blockchain techniques provide fundamental supports to credibly track the transactions of digital assets. Public blockchains, e.g., bitcoin, are often energy-consuming and low efficient. Therefore, an empirical study of operating permissioned blockchains in clouds is urgently needed. In this paper, we study the performance of Sawtooth, a well-known permissioned blockchain platforms from Hyperledger, in cloud environments. Our results provide insights for blockchain operators to optimize the performance of Sawtooth through adjusting the two configuration parameters, i.e., Scheduler and Maximum Batches Per Block. Our approach can be used to test other blockchain platforms.
Considering rapidly evolving Internet-of-Things services such as smart buildings, smart homes or secure e-health applications, the fog computing concept provides a technical basis for innovative application scenarios of the blockchain technology. We develop an enhancement of the fog computing architecture HCL-BaFog by the blockchain functionality to collect and securely share sensor data. They may arise from private IoT applications such as ambient assisted living which incorporate the need of an immutable, local storage and a sharing of protected real-time sensor data monitored at patients’ or people’s homes. Our proof-of-concept employs the fully virtualized functionality of a permissioned blockchain and a network of fog computing nodes and utilizes the container orchestration and management system Docker and the MultiChain framework. We investigate some basic performance metrics of our storage-and-sharing approach using a test bed of Raspberry Pi SBCs. Finally, some conclusions on the developed fog computing architecture with its integrated blockchain functionality are discussed and its current limitations are revealed.