Vger: a VRF based cross-chain mechanism for blockchains

Nowadays, the implemetation scheme of blockchain system generally has the defect of insufficient saclability, which can not meet the needs of large-scale applications, and imped its development. Sharding technology is regarded as the most likely solution to the current blockchain bottleneck, it divides the nodes of the blockchain network into each shard, which can maximize the transaction processing capacity of the system. In a sharding scheme, the blockchain is split into several blocks, networks with fewer nodes are created, so the reliability of the nodes in the network becomes critical. In this work, a blockchain sharding scheme based on Verifiable Random Functions(VRF) and node reputation is proposed. The nodes are randomly assigned to each shard by VRF, and the nodes are encouraged to work actively through the reputation score of the in-shard nodes. At the same time, the aggregation of malicious nodes is cotrolled to reduce the probability of fragmentation deterioration and influence of the whole blockchain.

Proof of Work (PoW) is a fundamental and widely adopted consensus mechanism in blockchain systems that enables effective consensus in permissionless environments, solely through block propagation without additional message exchange between nodes. However, PoW can result in excessive energy consumption and network centralization. This paper proposes VRF-PoW, a novel consensus protocol that reduces energy consumption while preserving the decentralized and permissionless nature of PoW. The VRF-PoW method integrates Verifiable Random Functions (VRFs) into the PoW process, reducing network energy consumption. To prevent Sybil attacks, this work introduces a pre-PoW phase. Further, this work validates VRF-PoW via a theoretical analysis and numerical evaluation. The results demonstrate that VRF-PoW significantly reduces energy consumption compared to the traditional PoW, while maintaining decentralization, stable block generation, and network liveness.

The blockchain technology has shown promise of transforming a variety of industries, it has captured significant interest for its ability to revolutionize multiple sectors through the facilitation of decentralized and secure transactions. Peer-to-peer architecture of blockchain provides strong security and trust-oriented guarantees, such as immutability, verifiability and decentralization. Nonetheless, it remains a considerable challenge to ensure the safety and efficiency of blockchain networks. Through consensus algorithms, existing blockchain can still maintain its integrity and safety; however, existing consensus tools face hurdles in addressing security threats and attacks. We need an advance method to improve security without slowing down the blockchain network. This paper proposes an advanced technique used to identify anomalous nodes in a blockchain network through the use of a machine learning technique that enhances the security and reliability of new node addition or a new transaction. A novel model for a blockchain network based on a vote-based consensus algorithm is presented, which enhances its fault-tolerant. The proposed method will monitor the network pattern by implementing machine learning algorithms to detect anomalies and prevent fraud. We will be making use of the vote-based approach, which will be performed by the nodes or the validators to check whether to approve or validate the transaction. Through simulations and experiments, the effectiveness of the approach can be evaluated. The model will attain an F1 of 0.68, precision of 0.70, and recall of 0.66 in the case of the Elliptic Bitcoin Transaction dataset in the context of unsupervised learning, which is better than the literature. Further, the inclusion of the machine learning-based node filtering approach to the consensus process will result in the reduction of the consensus latency of PBFT/DBFT by approximately 15%. The result shows that adding the functionality would enhance blockchain security, allowing for additional advancements.

The issue of admissibility of evidence in modern legal doctrine is difficult to overestimate, because it is this category of criminal proceedings that is one of the guarantees of its legality. At the same time, each of the possible types of evidence in criminal proceedings contains a system of its own characteristics and features that are related to its admissibility. This also applies to blockchain systems. It is worth noting that as of today, when martial law is in effect in Ukraine, the situation with the proper conduct of criminal proceedings has become somewhat more complicated. Within the framework of this work, the issue of understanding blockchain systems, their advantages and disadvantages was highlighted. According to the author’s algorithm, a study was conducted and the belonging of blockchain systems to electronic evidence was argued. This algorithm included the isolation of the characteristics of electronic evidence mentioned in the scientific literature and their comparison with the characteristics of blockchain systems. As a result, it was stated that blockchain systems belong to electronic evidence. The following should also be distinguished. In cases where blockchain is involved, the blockchain itself is a source of evidence, and cryptocurrency is actually evidence, because cryptocurrency is a digital asset, exists thanks to blockchain technology, is recorded in the form of transactions in the blockchain, and does not exist outside the corresponding blockchain network. The publication also prepared an overview and a substantive description of the most common investigative actions, as a result of which it is possible to obtain a blockchain system as a source of evidence: inspection (Article 237 of the Code of Criminal Procedure of Ukraine), temporary access to things and documents (Articles 159-166 of the Code of Criminal Procedure of Ukraine), search (Article 234 of the Code of Criminal Procedure of Ukraine), interrogation (Article 224 of the Code of Criminal Procedure of Ukraine), conducting an examination (Article 242 of the Code of Criminal Procedure of Ukraine), removal of information from electronic information systems (Article 263 of the Code of Criminal Procedure of Ukraine), control over the commission of a crime (Article 271 of the Code of Criminal Procedure of Ukraine), audio and video surveillance of a person (Article 260 of the Code of Criminal Procedure of Ukraine). In general, the peculiarity of the admissibility of blockchain systems as a source of evidence during martial law is associated with such objective circumstances as military operations that cause disruptions in the operation of electronic networks, the lack of stable access to the Internet, and the limited ability to attract specialists and experts in the field of digital technologies. This, in turn, complicates the proper recording of blockchain data, verification of their authenticity, and documentation of the evidence collection process. Further scientific research is required on the role and significance of blockchain systems as evidence, as well as the issues of their admissibility in civil, administrative, and commercial proceedings.

Incentivizing cooperative relay in UTXO-based blockchain network

Blockchain technology is being studied in many innovative applications, such as: cryptocurrencies, smart contracts, communication systems, healthcare, Internet of Things, financial systems, software development, electronic voting and many others. Using a transparent and fully distributed peer-to-peer blockchain architecture, applications benefit from a data-only model, in which “transactions” are accepted into the blockchain ledger and, if the system is functioning properly, cannot be modified or deleted. The transparency of blockchain systems makes it possible to store publicly available and irrefutable records. A peer-to-peer blockchain system provides verifiable ledger maintenance without centralized management, which solves the problems of a single point of failure and a single point of trust. The article deals with the issue of the security of application of accounting systems built on decentralized principles using blockchain technology. Particular attention is paid to the problem of the possibility of double spending in such accounting systems. The article exemplifies the reorganization of records in blockchain ledgers, performed by successfully carrying out a 51% attack on consensus algorithms based on proof of work. Given refinement of analytical expressions of 51% attack probability obtained in the works of S. Nakamoto and M. Rosenfeld using a more general model, namely, the model of independent players, where the probability of block formation by attackers and an honest network are independent events. The results of comparing of the success probability of a double-spending attack on the blockchain systems calculated according to different models are presented.

SummaryThe block chain is the emerging domain that offers the features like shared, immutable, and decentralized dataset that saves the asset's history. Security and storage are the most challenging aspect. The classical techniques' issues and challenges are an encouragement for developing a fresh block chain‐assisted IPFS model with access control policies. Hence, this research paper introduces an effective access control and authentication based on an interplanetary file system (IPFS)‐based block chain and access control system for attaining secured transactions. The developed method comprises five entities, that is smart contract, data owner, data requester, block chain and IPFS along with eight phases, to be exact setup, user registration, initialization, storage and data encryption, authentication, testing, access control, and decryption phase, to provide better access control and storage capacity. The proposed IPFS‐based block chain and access control system offered effective storage and secure transactions in the block chain network. The highest detection rate (0.870), lowest communication overhead (0.766 MB), and highest privacy rate (0.719) are all achieved by the proposed IPFS‐based block chain and access control system.

Blockchain technologies have been developing very fast recently. Ethereum, as the second generation of blockchain, can support smart contracts with various functions. Blockchain, combined with IoT technologies like RFID, can bring more security into IoT systems. It has been noted that just storing hash values, addresses and transaction records cannot meet the needs of various blockchain applications. Thus, how to test capacity of reading/writing data for blockchain and further make comparisons with the traditional relational databases needs to be paid attention. Although there has been some research on testing and analyzing the performance of blockchains, few studies focus on analyzing blockchains and relational databases. This test was conducted to analyze the capacities of reading/writing data and processing/recording transactions of blockchains and relational databases. Ethereum and MySQL are chosen as the representatives of blockchain and relational databases. This test has three aims: (1) getting the detailed data of the blockchain’s capacity of processing transactions; (2) identifying the bottleneck or potential bottleneck in blockchain systems; (3) putting forward a testing method and testing indexes which are reasonable, practical and compatible with the current development situations of blockchain systems. With the results data, it was concluded that the maximum data volume in single transaction on blockchain network was about 1/10 of MySQL. As for the time spent in processing single transaction, the blockchain network was 80–2000 times as much as MySQL. Thus, it’s recommended to store little-size data into blockchain. For more detailed testing, these indexes and testing method can be referenced.

The refinement of the division of labor among organizations in the field of ocean exploration has made the cross-organizational data sharing a common phenomenon. Although the blockchain system can solve the trust problem among organizations, the unstable Underwater Wireless Sensor Network (UWSN) and high network traffic costs of satellite network hindered the application of blockchain in the smart ocean. In this paper, we propose the smart ocean blockchain architecture (SOBC) that supports high transaction concurrency and saves network traffic to achieve trusted cross-organizational data sharing in the ocean exploration field. First, we design the SOBC architecture and use channels to isolate different businesses to ensure data privacy and high transaction concurrency. Second, we design blockchain smart contracts to implement data transmission rules among regulatory agencies, data providers and data demanders to achieve trusted data sharing. Finally, we design a channel-based consistency protocol to reduce the network traffic consumption when nodes reconnect to the core network. We use data collected from the spectrum detection platform to verify the effect of SOBC by simulating the ocean exploration network conditions. The experimental results show that the SOBC is superior to the Ethereum-based blockchain architecture in transactions concurrency supporting. Besides, compared with Ethereum, the SOBC reduces network traffic consumption by 70% under unstable network conditions.

An efficient Proof-of-Authority consensus scheme against cloning attacks

Blockchain as a potentially disruptive technology can advance many different fields, e.g., cryptocurrencies, supply chains, and the industrial Internet of Things. The next-generation blockchain ecosystem is expected to consist of various homogeneous and heterogeneous distributed ledgers. These ledger systems will inevitably require a certain level of proper cooperation of multiple blockchains to enrich advanced functionalities and enhance interoperable capabilities for future applications. The interoperability among blockchains will revolutionize current blockchain design principles, like the emergence of the Internet. However, the development of cross-blockchain applications involves much complexity regarding the variety of underlying cross-blockchain communication. With that regard, we propose an efficient, interoperable blockchain architecture, InterTrust, to support interoperability and trustworthiness among arbitrary blockchain systems (including homogeneous and heterogeneous blockchains). It consists of an atomic cross-chain communication protocol, which can be considered an agnostic protocol to integrate existing blockchain systems smoothly. InterTrust is powered by two innovative techniques: threshold signature scheme and trusted hardware. The threshold signature scheme guarantees consistency and verifiability in the target blockchain systems, and the trusted hardware guarantees trusted services among distinct blockchain systems. Combining these two techniques provides an efficient cross-chain communication protocol to facilitate atomic swaps and interoperable operations between different blockchain systems. Our interoperable architecture is robust to support arbitrary blockchain systems. We also present the security analysis on the scenarios of integrating our protocol into Byzantine fault tolerance based blockchain systems.

For a blockchain system, the network layer is of great importance for scalability and security. The critical task of blockchain networks is to provide a fast delivery of data. A rapid spread accelerates the transactions to be included into blocks and then confirmed. Existing blockchain systems, especially the cryptocurrencies like Bitcoin, take a simple strategy that requires relay nodes to verify all received transactions and then forward valid ones to all outbound neighbors. Unfortunately, this design is inefficient and slows down the transmission of transactions. In this paper, we introduce the concept of reputation and propose a novel relay protocol, RepuLay, to accelerate the transmission of transactions across the network. First of all, we design a reputation mechanism to help each node identify the unreliable and inactive neighbors. In this mechanism, two values are used to define one’s reputation. Each node keeps a local list of reputations of all its neighbors. Based on the reputation mechanism, RepuLay adopts probabilistic strategies to process transactions. More specifically, after receiving a transaction, the relay node verifies it with a certain probability, which is deduced from the first value of sender’s reputation. Next, the valid and unverified transactions are forwarded to some neighbors. Each neighbor has some probability to be chosen as a receiver and the probability is determined by its second value of reputation. Theoretically, we prove that our design can guarantee the quality of relayed transactions. Further simulation results confirm that RepuLay effectively accelerates the spread of transactions and optimize the usage of nodes’ bandwidths.

This paper proposes an architecture for biometric electronic identification document (e-ID) system based on Blockchain for citizens identity verification in transactions corresponding to the notary, registration, tax declaration and payment, basic health services and registration of economic activities, among others. To validate the user authentication, a biometric e-ID system is used to avoid spoofing and related attacks. Also, to validate the document a digital certificate is used with the corresponding public and private key for each citizen by using a user’s PIN. The proposed transaction validation process was implemented on a Blockchain system in order to record and verify the transactions made by all citizens registered in the electoral census, which guarantees security, integrity, scalability, traceability, and no-ambiguity. Additionally, a Blockchain network architecture is presented in a distributed and decentralized way including all the nodes of the network, database and government entities such as national register and notary offices. The results of the application of a new consensus algorithm to our Blockchain network are also presented showing mining time, memory and CPU usage when the number of transactions scales up.

With the rapid development of 5G, numerous data is generated in the blockchain-enabled industrial Internet of Things (IIoT). Although these peers in the blockchain system have the storage ability, they are far from meeting the storage requirements of the generated data. In addition, all data is stored in the blockchain network, which is unfriendly to applications that require real-time information. To address the above storage problems, this article proposes a block storage optimization method for blockchain-enabled IIoT, whose core idea is to conditionally select some blocks to store in the cloud. This method firstly models the selection conditions of blocks as a many-objective optimization problem, where the selection conditions include using probability, storage cost, space occupation, and transmission cost. Then, a cascading selection-based evolutionary algorithm (CSEA) for many-objective optimization is developed to solve the model and thereby obtain the optimal blocks stored in the cloud, where CSEA adopts the diversity-first principle. Finally, CSEA is first compared with seven state-of-the-art methods on two benchmark test suites for validating its ability to obtain reliable experimental results, and then is used to solve the proposed model. The corresponding results demonstrate that CSEA has high competitiveness, and our method can effectively address the storage problems above. In summary, this article provides a novel method for addressing the storage problem in the blockchain-enabled IIoT.

In recent years, consensus algorithms have gained significant importance in the context of blockchain networks. These algorithms play a crucial role in allowing network participants to reach agreements on the state of the blockchain without needing a central authority. The present study focuses on carrying out a systematic mapping of these consensus algorithms to explore in detail their use, benefits, and challenges in the context of blockchain networks. Understanding consensus algorithms is essential to appreciating how blockchain networks achieve the reliability and integrity of their distributed ledgers. These algorithms allow network nodes to reach agreement on the validity of transactions and the creation of new blocks on the blockchain. In this sense, consensus algorithms are the engine that drives trust in these decentralized networks. Numerous authors have contributed to the development and understanding of consensus algorithms in the context of blockchain networks. This revolutionary concept paved the way for numerous cryptocurrencies and blockchain systems. Despite advances in this field, significant challenges remain: centralization, fair token distribution, scalability, and sustainability. The energy consumption of blockchain networks, particularly those using algorithms such as Proof of Work, Proof of Stake, Delegated Proof of Stake, Proof of Authority, and hybrid algorithms (Proof of Work/Proof of Stake), has raised concerns about their environmental impact, motivating the scientific and technological community to investigate more sustainable alternatives that promise to reduce energy consumption and contribute to climate change mitigation. Furthermore, interoperability between different blockchains and security in specific environments, such as IoT, are areas that still require significant research attention. This systematic mapping not only seeks to shed light on the current state of consensus algorithms in blockchain, but also their impact on sustainability, identifying those algorithms that, in addition to guaranteeing integrity and security, minimize the environmental footprint, promoting a more efficient use of energy resources, being a relevant approach in a context in which the adoption of sustainable technologies has become a global priority. Understanding and improving these algorithms are critical to unlocking the full potential of blockchain technology in a variety of applications and industry sectors.