In recent years, the rapid development of blockchain technology and cryptocurrencies has influenced the financial industry by creating a new crypto-economy. Then, next-generation decentralized applications without involving a trusted third-party have emerged thanks to the appearance of smart contracts, which are computer protocols designed to facilitate, verify, and enforce automatically the negotiation and agreement among multiple untrustworthy parties. Despite the bright side of smart contracts, several concerns continue to undermine their adoption, such as security threats, vulnerabilities, and legal issues. In this paper, we present a comprehensive survey of blockchain-enabled smart contracts from both technical and usage points of view. To do so, we present a taxonomy of existing blockchain-enabled smart contract solutions, categorize the included research papers, and discuss the existing smart contract-based studies. Based on the findings from the survey, we identify a set of challenges and open issues that need to be addressed in future studies. Finally, we identify future trends.

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Blockchain smart contracts: Applications, challenges, and future trends

Smart grids are the backbone of existing energy production and supply scenario in today’s society. Gradual increasing demand of energy has certainly emphasized the significance and provenance of reliability and predictive aspects over smart grids. Conventional smart grids under perform in terms of self-aware behavior, especially in delay tolerance, energy requirement, and dissemination of monitoring notions. Highly distributed geographical distribution sometimes cause problems for smart grids to provide necessary services to both the consumers and prosumers. Internet of Things (IoT) is thus integrated with smart grids to facilitate distributed monitoring services for smooth running of the smart grid. Although, IoT has remarkably supported smart grids to perform smarter than ever, it lacks in security, decentralization, transparency, and trust-less approaches. Thus, blockchain is envisaged to leverage minimizing such gaps and to pave new horizon in the blockchain-IoT enabled smart grid monitoring. In this paper, we investigate how blockchain and IoT together can improve existing smart grid ecosystem toward facilitation of better monitoring services. We do this via a Systematic Literature Review. Firstly, we present preliminaries behind the study, followed by in-depth review of different domains of IoT-based smart grid monitoring. Next, we discuss various attributes of blockchain-IoT derived smart grid management schemes. Then, we discuss possible opportunities and benefits of using blockchain with respect to blockchain-IoT based smart grid monitoring. Finally, we illustrate open research challenges and future directions in the aforementioned aspects. The article concludes that with certain changes in current blockchain technology, it can surely encompass the direction of enhanced monitoring of IoT based smart grid.

Reviewing the opportunities, challenges, and future directions for the digitalization of energy

Blockchain is a distributed secure ledger that eliminates the need for centralized authority to store data. The centralized approach has several limitations as it is a Single-Point-of-Failure and a third-party might be needed. Blockchain, on the other hand, provides decentralized, secure and trustless framework that eliminates the need for a third party and enhances fault tolerance. In this paper, we investigate the potentials of customizing the behavior of Blockchain network based on the applications' requirements. In particular, we conduct several experiments to evaluate the performance of the Hyperledger Fabric (HLF) – a permissioned blockchain framework. Seven different scenarios were tested to depict the Blockchain behavior in terms of end-to-end transaction latency and network throughput. Moreover, in these scenarios, the impact of different parameters, such as the batch-timeout, batch size, and number of endorsing peers, has been studied.

Performance Evaluation of Hyperledger Fabric

Smart contracts have been well-received by researchers and practitioners for the unique features of automatic execution, transparency, and nontampering in a blockchain environment. However, little is known about the current development status of knowledge and practice regarding the application of smart contracts in various industries, especially from the procurement perspective. Thus, this paper aims to address the gap with a mixed method of bibliometric analysis and systematic literature review. Based on the evaluation of 174 filtered publications, the review has analyzed the current development status of this research area with its distributions in years and journals, cooperation networks between authors, institutions, and countries, keywords cooccurrence network, and classifications of the application of smart contracts. The results show the application of smart contracts has attracted global attention since 2016 with the Ethereum and Hyperledger fabric as the main platforms in various industries, especially in information communication technology (ICT), public management, supply chain, energy, finance, and healthcare. Various functions and benefits of smart contracts, as well as their potential advantages, have been identified and articulated from the procurement perspective. A research framework has also been developed to highlight future procurement needs in business operations across the industries via an integrated procurement approach of smart contracts.

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A Review of Smart Contracts Applications in Various Industries: A Procurement Perspective

The emerging blockchain technology helps in the decentralization of transactions, where every participant network verifies and validates the transaction making it immutable. With the rapid expansion of the technology, transactional data which is stored and validated is also increasing. The blockchain technology came into prominence largely due to the bitcoin and the security aspects of the technology. This technology is comparatively fast, secure and efficient. This paper discusses the generalized overview, different algorithms to reach consensus, system workflows and various security aspects of handling, transacting and storing data. This paper also throws light Smart Contracts and their applications.

Blockchain-based Security Solutions to Preserve Data Privacy And Integrity

In today’s time, we use Leave Application System managed by some central authority. This can lead to corruption, misuse by a single authority or unnecessary time for approval. So, in this paper, we have developed smart contract architecture for Leave Management System using Solidity and Ethereum, which is a decentralized app architecture leveraged from Blockchain Technology. We also include smartphones as IoT devices by which any client can use this app. Due to the resource-constrained nature of these devices, the smart contract app is coupled with an alternative centralized architecture which is a classic client/server architecture with an underlying Blockchain backend.

Develop Leave Application using Blockchain Smart Contract

In today’s time, the number of IoT devices are increasing rapidly. We everyday hear about Amazon echo, Google Mini, Smart watches etc. These devices collect confidential data of a person and as most of these systems follow centralized architecture approach, So most of the data on internet is basically managed by some central authority or organization. Though these organizations have strict policy regarding data misuse or changing of data without consent but one can’t overlook the fact that these organizations have the ability to do so. Blockchain helps solve such problem as it is not managed by single party if somebody tries to change data in his Blockchain then the hash of the particular block will no longer match and the particular Blockchain will become invalid and other Blockchain will still be intact and therefore users data won’t be compromised. But due to high resource requirement, it becomes problem to run complete Blockchain node on all IoT devices mainly on low power or memory devices. In this paper, we have developed decentralized architecture leveraged from Blockchain technology coupled with an alternative centralized cloud architecture which is a classic client/server architecture with an underlying Blockchain at back-end support with smart contract application written in Solidity language at Ethereum platform. We implement this framework and show how this architecture prevent data misuse by using functionality of Blockchain without requiring the all IoT devices to actually run a Blockchain node. For an end-user experience, it will appear to be same as a normal web app and from the developers perspective, the smart contract application will have similar software design to current web apps thus allowing an easy transition for both of centralized and decentralized methods while still retaining the trust of decentralization.

Vinayak Singla

Papers

Develop Leave Application using Blockchain Smart Contract

A Blockchain Based Solution for Securing Data of IoT Devices