Recent Trends in Blockchain and Its Applications

As is well known, smart contracts on the blockchain store plenty of digital assets, and these contracts deployed on the blockchain are difficult to be modified. For this reason, the analysis and detection of smart contract vulnerabilities have received extensive attention. Smartcheck, a typical Java-implemented static analysis tool of smart contracts, is capable of converting Solidity source code into path diagrams based on the lexical and syntactic analysis, and finds smart contract vulnerabilities by path matching. Although Smartcheck can analyze most of the real-world vulnerabilities, some imperceptible vulnerabilities may be ignored, causing huge economic losses. In order to address these issues, we develop a new tool named MSmart to analyze the vulnerabilities of high risk such as timestamp dependence vulnerabilities, integer overflow vulnerabilities, self-destruct vulnerabilities, etc. MSmart converts the smart contract source code into an intermediate representation, and looks for smart contract vulnerabilities based on intermediate representation and XPath rules. We add new intermediate representation rules of Smartcheck to detect more kinds of vulnerabilities and optimize existing rules to suit the complexity of smart contract. We also implemented smart contract batch detection to shorten the time it takes to find vulnerabilities. To analysis the performance of MSmart, we collect 6000 real-world contracts from Etherscan and design some comparative experiments with other tools. The results of experiment show that MSmart is able to analyze related vulnerabilities better, and false positives and false negatives have been reduced due to our improvements. Full article

Vehicular Ad Hoc Network (VANET) is an important part of the modern intelligent transportation system, which can provide vehicle communication at a certain distance. More importantly, VANET can provide route planning and autonomous driving for drivers by analyzing data. However, VANET’s data privacy and security are a huge challenge when serving drivers. In this paper, we propose a VANET data-sharing model (DSVN) that combines ciphertext-based attribute encryption (CP-ABE), blockchain, and InterPlanetary File System (IPFS). DSVN uses an outsourced and revocable ciphertext policy attribute-based encryption (ORCP-ABE) scheme, which is improved based on CP-ABE. ORCP-ABE uses key encryption key (KEK) trees to manage user attribute groups and revoke user-level attributes. It eliminates redundant attributes in the access policy by attribute-weighted access trees. Moreover, DSVN has no single point of failure. We demonstrate the indistinguishability under the chosen-plaintext attack (IND-CPA) security of DSVN by a game based on the computational Diffie–Hellman (CDH) assumption. Experimental results show that DSVN can store and share data with low overhead. Additionally, it can revoke attributes of users safely. Full article

Blockchain is a new and modern technology that is gradually being used in various fields due to its ability to decentralize and organize secure and reliable data exchange and storage. One of the related research areas generating increasing interest is the field of education, with particular focus on the digitization and automation of educational management processes and the ability to store and verify digital documents about student progress. The main goal of this study is to develop a platform that creates a unified digital register of students’ educational achievements, which is one of the most pressing issues in the field of education, based on the Ethereum blockchain architecture. Blockchain is expensive; therefore, there is a need to consider performance criteria when evaluating any decision made about the technology, especially the most important aspects such as predicting traffic behavior, estimating transaction costs and providing the necessary indicators of system quality and functionality. However, most research ignores the evaluation of performance indicators, such as throughput, the speed of transactions and the amount of data stored in the Ethereum blockchain database, which are the main evaluation criteria. This paper aims to eliminate this gap by evaluating the performance of the developed platform and by discussing the obtained experimental results. Thus, the main results of this work are the design and deployment of a blockchain platform and the analysis of its transaction costs. We conclude that the proposed blockchain solution is applicable as a system for the accounting and verification of loans and student academic achievements. Full article

In recent years, blockchain technology has received increasing attention in the real estate literature. Moreover, recent evidence suggests that blockchains could provide some added benefits for the real estate sector even in the current hybrid settings, where blockchain is usually just an add-on to existing systems. This research provides an up-to-date and systematic understanding of blockchain’s theoretical potential, pros, and cons for the real estate sector. The research aims to understand why and where to apply blockchain in real estate by conducting a systematic review that identified 296 relevant documents and performed a thematic content analysis. The identified blockchain adoption proposals were classified using standardized real estate vocabulary. Most of the literature focused on blockchain possibilities within land administration, followed by property transactions, real estate investment, leasing and renting, and real estate administration. However, real estate development and real estate maintenance did not appear as attractive real estate subsectors for blockchain. This paper provides a detailed analysis of blockchain technology’s possibilities for each real estate subsector, i.e., blockchain merits, and discusses the pros and cons. Last, this review provides suggestions for future research directions. Full article

In recent years, with the continuous development of UAV technology, the application of the UAV swarm in the military has been a global focus of research. Although it can bring a series of benefits in autonomous cooperation, the traditional UAV management technology is prone to hacker attacks due to many security issues, such as a single point of failure brought by centralized management and the lack of reliable identity authentication. This paper studies the advantages and the recent advances of the blockchain in UAV swarm, proposes a blockchain-based UAV swarm identity management model (B-UIM-M), and establishes a distributed identity authentication scheme based on the distributed identity identifier (DID) under this model. Moreover, to ensure the safe transmission of UAV communication data, a secure communication architecture based on blockchain and a set of secure transmission protocols were designed, combined with cryptography. In the current military field, there is no similar application case of the UAV swarm identity management model and distributed identity authentication. The feasibility and security of the proposed scheme are proved through experiments and security analyses. Full article

Currently, blockchain is facing a serious storage explosion problem. While most storage scaling schemes are focused on permissionless blockchain, we propose the ring-overlap mechanism for consortium blockchain and use it to scale Hyperledger Fabric. In our scheme, all accounting nodes are divided into clusters, and each cluster contains several nodes; then, a portion of the entire block data is stored in a cluster. Block data is stored overlappingly on some cluster nodes, and each block is guaranteed to have some copies in a cluster. Theoretical analysis and simulation show that the storage occupied by nodes is significantly reduced in blockchain applications with frequent transactions, and the mechanism can still guarantee data integrity in the case of partial node failures in a single cluster. Furthermore, for transaction-frequent applications, storage space consumption can be significantly reduced without increasing excessive query time overhead. Full article

With the success of Bitcoin and the introduction of different uses of Blockchain, such as smart contracts in Ethereum, many researchers and industries have turned their attention to applications that use this technology. In response to the advantages and disadvantages of Blockchain, similar technologies have emerged with alterations to the original structure. Distributed ledger technology (DLT) is a generalized distributed technology encompassing these new variants. Several studies have examined the challenges and applications of Blockchain technology. This article explores the possibilities of using different DLTs to solve traditional distributed computing problems based on their advantages and disadvantages. In this paper, we provide an overview and comparison of different DLTs, such as Hashgraph, Tangle, Blockchains, Side Chain and Holochain. The main objective of the article is to examine whether distributed ledger technologies can replace traditional computational methods in other areas instead of traditional methods. Based on the primary keywords, we conducted a systematic review of more than 200 articles. Based on the data extracted from articles related to the use of DLT, we conclude that that DLTs can complement other methods, but cannot completely replace them. Furthermore, several DLTs such as Sidechain, Holochain and Hashgraph are still in their infancy, and we foresee much research work in this area in the coming years. Full article

The market of oil and gas has many particularities, once it is a natural resource of great value. Due to the fact the resource is owned by nations, it is highly regulated. The volumes traded are high; for this reason, their calculation needs to be performed very carefully, meeting not only the uncertainties and metrological control, but also particularly the tracking of the activities. The technical regulations of measurement adopted by the countries carefully follows many guidelines. The reason is that the established volumes directly affect the calculation of royalties and profit sharing in concession agreements or even a simple ownership shift of the products. Therefore, it is an application with a lot of responsibility, involving a large amount of equipment, software, and execution processes. Therefore, the transfer of data among different entities requires total transparency and security. Blockchain technology, which has been initially developed for the financial market, presents itself as an alternative to ensure reliability, from the sensors in the field to the effective generation of the Monthly Report on the petroleum and natural gas production unit, which is the basic document for determining the remuneration of the owners of the product. This paper presents a technical solution for creating the blockchain validation blocks by the MAC (Media Access Control Address) addressing, which in turn comes from the communication boards of the flow computers and from the Supervisory Stations. There are limitations to extending this solution to the level of field sensors due to the current links of communication, but also because of the way that historical, events and alarm databases of the flow computers are generated. Once these devices exhibit an elevated degree of safety in their operation, the solution herein presented adds a high level of reliability in the fiscal measurement and/or custody transfer. Full article

Consensus protocols stand behind the success of blockchain technology. This is because parties that distrust each other can make secure transactions without the oversight of a central authority. The first consensus protocol emerged with Bitcoin. Since then, many others have appeared. Some of them have been implemented by official blockchain platforms, whereas others, for the time being, remain as proposals. A blockchain consensus is a trade-off. The new solutions promise to overcome the known drawbacks of blockchain, but they may also bring new vulnerabilities. Moreover, blockchain performance metrics are not clearly defined, as some metrics, such as delay and throughput, which are key factors for the efficiency of standard networks, are purposely constrained by most mainstream blockchain platforms. The main body of this paper consolidates knowledge of blockchains, focusing on the seminal consensus protocols in large-scale market capitalization platforms, and how consensus is achieved for large-scale, decentralized, blockchain architectures. The benefits, limitations, and tradeoffs, as well as the subsequent trend in current consensus development, and its limitations as a general paradigm, are highlighted. The paper also sheds light on overlooked potential performance metrics, and it proposes some novel solutions to some of the identified problems. Full article

Blockchain is making a big impact in various applications, but it is also attracting a variety of cybercrimes. In blockchain, phishing transfers the victim’s virtual currency to make huge profits through fraud, which poses a threat to the blockchain ecosystem. To avoid greater losses, Ethereum, one of the blockchain platforms, can provide information to detect phishing fraud. In this study, to effectively detect phishing nodes, we propose a phishing node detection approach as message passing based graph convolution network. We first form a transaction network through the transaction records of Ethereum and then extract the information of nodes effectively via message passing. Finally, we use a graph convolution network to classify the normal and phishing nodes. Experiments show that our method is effective and superior to other existing methods. Full article

Whereas the use of distributed ledger technologies has previously been limited to cryptocurrencies, other sectors—such as healthcare, supply chain, and finance—can now benefit from them because of bitcoin scripts and smart contracts. However, these applications rely on oracles to fetch data from the real world, which cannot reproduce the trustless environment provided by blockchain networks. Despite their crucial role, academic research on blockchain oracles is still in its infancy, with few contributions and a heterogeneous approach. This study undertakes a bibliometric analysis by highlighting institutions and authors that are actively contributing to the oracle literature. Investigating blockchain oracle research state of the art, research themes, research directions, and converging studies will also be highlighted to discuss, on the one hand, current advancements in the field and, on the other hand, areas that require more investigation. The results also show that although worldwide collaboration is still lacking, various authors and institutions have been working in similar directions. Full article

Anonymity and privacy in the electoral process are mandatory features found in any democratic society, and many authors consider these fundamental civil liberties and rights. During the election process, every voter must be identified as eligible, but after casting a vote, the voter must stay anonymous, assuring voter and vote unlinkability. Voter anonymity and privacy are the most critical issues and challenges of almost all electronic voting systems. However, vote immutability must be assured as well, which is a problem in many new democracies, and Blockchain as a distributed technology meets this data immutability requirement. Our paper analyzes current solutions in Blockchain and proposes a new approach through the combination of two different Blockchains to achieve privacy and anonymity. The first Blockchain will be used for key management, while the second will store anonymous votes. The encrypted vote is salted with a nonce, hashed, and finally digitally signed with the voter’s private key, and by mixing the timestamp of votes and shuffling the order of cast votes, the chances of linking the vote to the voter will be reduced. Adopting this approach with Blockchain technology will significantly transform the current voting process by guaranteeing anonymity and privacy. Full article

A smart grid is an intelligent electricity network that allows efficient electricity distribution from the source to consumers through telecommunication technology. The legacy smart grid follows the centralized oligopoly marketplace for electricity trading. This research proposes a blockchain-based electricity marketplace for the smart grid environment to introduce a decentralized ledger in the electricity market for enabling trust and traceability among the stakeholders. The electricity prices in the smart grid are dynamic in nature. Therefore, price forecasting in smart grids has paramount importance for the service providers to ensure service level agreement and also to maximize profit. This research introduced a Stackelberg model-based dynamic retail price forecasting of electricity in a smart grid. The Stackelberg model considered two-stage pricing between electricity producers to retailers and retailers to customers. To enable adaptive and dynamic price forecasting, reinforcement learning is used. Reinforcement learning provides an optimal price forecasting strategy through the online learning process. The use of blockchain will connect the service providers and consumers in a more secure transaction environment. It will help tackle the centralized system’s vulnerability by performing transactions through customers’ smart contracts. Thus, the integration of blockchain will not only make the smart grid system more secure, but also price forecasting with reinforcement learning will make it more optimized and scalable. Full article