The blockchain has a great vogue in recent years, and its core consensus algorithms also become the focus of research. At present, most of the research on consensus mechanisms are oriented to the public blockchain and based on existing consensus mechanisms or sophisticated distributed algorithms. Various application scenarios have been developed based on the consortium blockchain, while few researchers pay attention to customize consistency algorithms. Moreover, there is a trade-off between security and performance in designing consensus mechanisms. We propose a novel consensus algorithm called proof of vote (PoV), where the distributed nodes controlled by consortium members could reach consensus and come to a decentralized arbitration by voting. PoV separates the voting rights and bookkeeping rights with the essential idea of establishing different security identities for network nodes. Contrary to the third-party intermediary or uncontrollable public awareness, the production and verification of PoV blocks are decided by the voting results among the core consortium members. We theoretically prove that PoV blocks can reach transaction finality by only one confirmation. Compared with the total traffic complexity of BFT-based consensus, PoV has just that of O(3N_c), which is a great improvement when the number of nodes is over 100.

Array codes are used widely in data storage systems such as redundant array of independent disks. The row-diagonal parity (RDP) codes and EVENODD codes are two popular double-parity array codes. The increasing capacity of hard disks demands better fault tolerance by using array codes with three or more parity disks. Although many extensions of RDP and EVENODD codes have been proposed, their main drawback is high decoding complexity. In this paper, we propose a unified form of RDP and EVENODD codes under which RDP codes can be treated as shortened EVENODD codes. Moreover, an efficient decoding algorithm based on an LU factorization of a Vandermonde matrix is proposed. The LU decoding method is applicable to all the erasure patterns of RDP and EVENODD codes with three parity columns. It is also applicable to the erasure decoding of RDP and EVENODD codes with more than three parity columns when the number of continuous surviving parity columns is no less than the number of erased information columns and the first parity column has not failed. The proposed efficient decoding algorithm is also applicable to other Vandermonde array codes, with less decoding complexity than that of the existing method.

The metaverse gradually evolves into a virtual world containing a series of interconnected sub-metaverses. Diverse digital resources, including identities, contents, services, and supporting data, are key components of the sub-metaverse. Therefore, a Domain Name System (DNS)-like system is necessary for efficient management and resolution. However, the legacy DNS was designed with security vulnerabilities and trust risks due to centralized issues. Blockchain is used to mitigate these concerns due to its decentralized features. Additionally, it supports identity management as a default feature, making it a natural fit for the metaverse. While there are several DNS alternatives based on the blockchain, they either manage only a single type of identifiers or isolate identities from other sorts of identifiers, making it difficult for sub-metaverses to coexist and connect with each other. This article proposes a M ulti- I dentifier management and resolution S ystem (MIS) in the metaverse, supporting the registration, resolution, and inter-translation functions. The basic MIS is portrayed as a four-tier architecture on a consortium blockchain due to its manageability, enhanced security, and efficiency properties. On-chain data is lightweight and compressed to save on storage while accelerating reading and writing operations. The resource data is encrypted based on the attributes of the sub-metaverse in the storage tier for privacy protection and access control. For users with decentralization priorities, a modification named EMIS is built on top of Ethereum. Finally, MIS is implemented on two testbeds and is available online as the open-source system. The first testbed consists of 4 physical servers located in the UK and Malaysia while the second is made up of 200 virtual machines (VMs) spread over 26 countries across all 5 continents on Google Cloud. Experiments indicate that MIS provides efficient reading and writing performance than the legacy DNS and other public blockchain-based workarounds including EMIS and Ethereum Name Service (ENS).

Smart contracts, programs running on a blockchain, play a crucial role in driving Web 3.0 across a variety of domains, such as digital finance and future networks. However, they currently face significant security vulnerabilities that could result in potential risks and losses. This paper outlines the inherent vulnerabilities of smart contracts, both those typical of their applications and those unique to Web 3.0 applications. We then systematically classify the techniques based on their core approach to detecting vulnerabilities in smart contracts. Using these approaches, we conduct a comparative analysis of existing tools in terms of their vulnerability coverage, detection effectiveness, open-source availability, and integration capabilities. Finally, we present the Co-Governed Sovereignty Multi-Identifier Network (CoG-MIN) as a case study to demonstrate the significance of smart contract application security in establishing a community with a shared future in cyberspace during the Web 3.0 era and anticipate future research directions with challenges. To conclude, this study addresses the gap in integrating existing smart contract security research with the advancement of Web 3.0 development, while also providing recommendations for future research directions.

Binary maximum distance separable (MDS) array codes are a special class of erasure codes for distributed storage that not only provide fault tolerance with minimum storage redundancy but also achieve low computational complexity. They are constructed by encoding k information columns into r parity columns, in which each element in a column is a bit, such that any k out of the k + r columns suffice to recover all information bits. In addition to providing fault tolerance, it is critical to improve repair performance in practical applications. Specifically, if a single column fails, our goal is to minimize the repair bandwidth by downloading the least amount of bits from d healthy columns, where k ≤ d ≤ k + r - 1. If one column of an MDS code is failed, it is known that we need to download at least 1/(d - k + 1) fraction of the data stored in each of d healthy columns. If this lower bound is achieved for the repair of the failure column from accessing arbitrary d healthy columns, we say that the MDS code has optimal repair. However, if such lower bound is only achieved by d specific healthy columns, then we say the MDS code has weak-optimal repair. In this paper, we propose two explicit constructions of binary MDS array codes with more parity columns (i.e., r ≥ 3) that achieve asymptotically weak-optimal repair, where k + 1 ≤ d ≤ k + ⌊(r - 1)/2⌋, and “asymptotic” means that the repair bandwidth achieves the minimum value asymptotically in d. Codes in the first construction have odd number of parity columns and asymptotically weak-optimal repair for any one information failure, while codes in the second construction have even number of parity columns and asymptotically weak-optimal repair for any one column failure.

Multi‐field packet classification is not only an indispensable and challenging functionality of existing network devices, but it also appears as flow tables lying at the heart of the forwarding plane of software defined networking age. Despite almost two decades of research, algorithmic solutions still fall short of meeting the line‐speed of high‐performance network devices. Although decomposition‐based approaches, such as cross‐producting and recursive flow classification (RFC), can achieve high lookup rate by performing a parallel search on chunks of the packet header, both of them suffer from memory explosion problem during aggregation. In this study, the authors propose an HybridRFC, a memory‐efficient recursive scheme for multi‐field packet classification. By addressing the embedded problem of the RFC caused by uncontrollably expanded cross‐product tables, HybridRFC can not only reduce the memory consumption to a practical level but also improve pre‐processing performance significantly. Experimental results show that the memory requirement of HybridRFC is two orders of magnitude less than RFC, as well as three orders of speed‐up on the performance of table building on average.