Yu Qiu, Haijun Zhang, Kai Sun, Keping Long · 5 authors
Recently, Web3 has received extensive attention as the next generation Internet and is in rapid development, which can highly integrate the physical world with the digital world. The blockchain that can build trust and fog computing with distributed computing mode can fit well with the decentralization idea of Web3. The combination of the two can provide an effective solution for the implementation of Web3. This article proposes a new network architecture, fog-assisted blockchain radio access network (FogBC-RAN), which supports stable and mutual trust connections on a global scale, and can smoothly coordinate multi-dimensional resources to support new services such as holographic communication, digital twin, and sensory interconnection. With the interconnection of ten thousand chains in the future Web3, the cross-chain information transfer process based on Polkadot for charging sharing is presented, which can realize flexible cross-chain transactions. Meanwhile, for the mainstream computing-intensive applications of Web3, considering the latency, energy consumption and transaction cost, a computing offloading strategy based on matching game is proposed to minimize the system cost. Finally, the simulation results demonstrate the effectiveness of the offloading mechanism proposed in FogBC-RAN.
By combining distributed generation, battery storage, and smart meters, microgrid performance can be enhanced. As a result, distributed energy resources (DER) can be intelligently controlled via online platforms. Through integration, prosumers that use decentralized resources like wind power have replaced conventional power customers. Due to the growth and digitalization of the power distribution infrastructure, a new method of exchanging electricity in community microgrids called peer-to-peer (P2P) intratrading has emerged. Blockchain technology is used because it is transparent, secure, and completes transactions quickly. Prosumers, consumers, and owners of renewable energy sources may now trade energy more easily amongst one another. This study develops the P2P paradigm to create a self-sufficient community microgrid system for trading energy. Incorporating peer-to-peer energy trades and a battery backup system, the suggested technique uses blockchain to simulate a decentralized microgrid energy market. The microgrid P2P market's clearing price is established by taking into account customers' expected reactions to price changes, incentivizing consumers and prosumers to alter their patterns of energy usage. A cryptocurrency called Cosmos that is mined and distributed using blockchain technology is also included in the P2P market idea. The results show how automated P2P commerce and adjustable energy storage enable end users to save energy and become more independent. This paper provides a sustainable microgrid energy market model and suggests an approach to improve security by incorporating blockchain technology into current energy management systems. In summary, the paper offers a design paradigm for an independent microgrid system that makes use of distributed energy sources. It demonstrates how end users may gain from energy efficiency and independence while highlighting the possibilities of P2P energy trade and storage variety offered by blockchain. This thorough method provides information on creating a sustainable microgrid energy market and illustrates how blockchain technology can be used to increase the safety of energy management systems.
Blockchain is a distributed ledger technology that enables cryptocurrencies, such as Bitcoin and Ethereum. However, it suffers from the scalability problem, which means that not all generated blocks can be added to the chain in a timely manner. For the Internet of Things (IoT), which involves a large number of interconnected devices, blockchain is infeasible due to the scalability issue. Instead, a different distributed ledger technology, IOTA Tangle, is expected to be widely adopted in IoT applications. Nevertheless, it has been found that the tip selection and weight update operation of IOTA Tangle could negatively affect its efficiency. To tackle this problem, Fishing Net Topology (FNT) was proposed to completely eliminate the tip selection and weight update operation. However, in our research, we noticed that the width of the fishing net used in FNT remains unchanged, which has a serious impact on the performance of FNT. In this paper, we focus on Wireless Sensor Networks (WSNs), which are often used to implement IoT applications. Specifically, we present a secure data storage scheme based on FNT for WSN, Adaptive FNT (AFNT). Our experimental results indicate that AFNT outperforms FNT in terms of layer number, average fishing net width, percentage of over-approved nodes, and percentage of over-approving nodes.
The alliance chain system is a distributed ledger system based on blockchain technology, which can realize data sharing and collaboration among multiple parties while ensuring data security and reliability. The Practical Byzantine Fault Tolerance (PBFT) consensus algorithm is the most popular consensus protocol in the alliance chain, but the algorithm has problems such as high complexity and too simple election of the master node, which will make PBFT unable to be applied in scenarios with too many nodes. At the same time, there are certain security issues. In order to solve these problems, this paper proposes an improved Byzantine consensus algorithm, Polymerization Signature and Reputation Value PBFT (P-V PBFT). Firstly, the consistency protocol process is improved based on the aggregate signature technology. The simulation results show that the P-V PBFT algorithm can effectively reduce the overhead of network transmission, and the time complexity of the algorithm decreases exponentially, which improves the efficiency of the consensus process. Secondly, the node reputation election mechanism is introduced to elect the primary node, and the security analysis is carried out to verify the fairness and security of the primary node election of the P-V PBFT algorithm. Therefore, as a feasible improvement of the blockchain consensus protocol, the P-V PBFT algorithm can provide more efficient and secure guarantee for the blockchain system in practical application.
Javier José Díaz Rivera, Waleed Akbar, Talha Ahmed Khan, Muhammad Afaq · 5 authors
Zero Trust Networking (ZTN) is a security model where no default trust is given to entities in a network infrastructure. The first bastion of security for achieving ZTN is strong identity verification. Several standard methods for assuring a robust identity exist (E.g., OAuth2.0, OpenID Connect). These standards employ JSON Web Tokens (JWT) during the authentication process. However, the use of JWT for One Time Token (OTT) enrollment has a latent security issue. A third party can intercept a JWT, and the payload information can be exposed, revealing the details of the enrollment server. Furthermore, an intercepted JWT could be used for enrollment by an impersonator as long as the JWT remains active. Our proposed mechanism aims to secure the ownership of the OTT by including the JWT as encrypted metadata into a Non-Fungible Token (NFT). The mechanism uses the blockchain Public Key of the intended owner for encrypting the JWT. The blockchain assures the JWT ownership by mapping it to the intended owner's blockchain public address. Our proposed mechanism is applied to an emerging Zero Trust framework (OpenZiti) alongside a permissioned Ethereum blockchain using Hyperledger Besu. The Zero Trust Framework provides enrollment functionality. At the same time, our proposed mechanism based on blockchain and NFT assures the secure distribution of OTTs that is used for the enrollment of identities.
Lioba Heimbach, Lucianna Kiffer, Christof Ferreira Torres, Roger Wattenhofer
With Ethereum's transition from Proof-of-Work to Proof-of-Stake in September 2022 came another paradigm shift, the Proposer-Builder Separation (PBS) scheme. PBS was introduced to decouple the roles of selecting and ordering transactions in a block (i.e., the builder), from those validating its contents and proposing the block to the network as the new head of the blockchain (i.e., the proposer). In this landscape, proposers are the validators in the Proof-of-Stake consensus protocol, while now relying on specialized block builders for creating blocks with the highest value for the proposer. Additionally, relays act as mediators between builders and proposers. We study PBS adoption and show that the current landscape exhibits significant centralization amongst the builders and relays. Further, we explore whether PBS effectively achieves its intended objectives of enabling hobbyist validators to maximize block profitability and preventing censorship. Our findings reveal that although PBS grants validators the opportunity to access optimized and competitive blocks, it tends to stimulate censorship rather than reduce it. Additionally, we demonstrate that relays do not consistently uphold their commitments and may prove unreliable. Specifically, proposers do not always receive the complete promised value, and the censorship or filtering capabilities pledged by relays exhibit significant gaps.
Fengyang Guo, Xun Xiao, Artur Hecker, Schahram Dustdar
IOTA is a recent distributed ledger technology that relies on Directed Acyclic Graph (DAG) for its ledger organization. To improve IOTA mechanisms, the state of the art methodology employs graph analysis and, for that, heavily relies on synthetic graph generation. Herein, the most popular generation method simulates IOTA protocol execution. Although this method produces realistic IOTA ledgers, it requires too much memory and time due to repeated random walks on the DAG. In this paper, we propose an alternative Graph Generation and Refinement (GraGR) algorithm designed to generate realistic IOTA ledgers while strongly relaxing memory and timing constraints. The evaluations show that, compared to the state of the art, GraGR can generate a ledger with the same properties with only half of memory and up to 10 times faster.
Haoran Zhu, Zhi Chen, Jelena Mišić, Vojislav B. Mišić · 6 authors
Bitcoin is the largest PoW blockchain, which currently uses the longest-chain protocol for chain selection and is vulnerable to various attacks like stubborn mining attack. As a variant of selfish mining attack, stubborn mining attack usually has 7 types of strategies, each of which does damage to the blockchain system. GHOST is another chain-selection protocol, which has been demonstrated to make the blockchain system more secure than the longest-chain protocol under selfish mining attack. There were studies on stubborn mining in perfect GHOST blockchains and they only studied two types of stubborn mining strategies. But it is a fact of life that the blockchain is an imperfect network due to ubiquitous network congestion and/or attacks. This paper aims to explore a simulation-based approach to quantitatively evaluate the threat capability of all 7 stubborn mining strategies. We first develop all stubborn strategies in imperfect GHOST blockchains. Then we evaluate miner revenues and system throughput over different network conditions. The results show that the lead-fork-stubborn strategy is the dominant strategy for attackers when they have more than 33% total computing power. The stubborn attackers with less than 20% total computing power lose their revenue whichever stubborn mining strategy is used. The blockchain with high network quality still has the risk of significant throughput downgrade. Our work can help the stubborn mining attack detection and secure blockchain system design.
Named-Data Networking (NDN) is a novel network that secures network communication by fetching semantically named and secured data. All data packets in NDN are signed by producers and verified by data consumers. Therefore, it is vital to have producers' certificates available all the time. In this paper, we describe the design of CLedger, a secure distributed certificate ledger, to ensure certificate availability in NDN. CLedger logs certificate records in an immutable Directed Acyclic Graph (DAG) structure and replicates the DAG among a set of distributed loggers. We implemented CLedger using NDN's pub/sub API, and evaluated our design through an emulated deployment setting. Our initial evaluation results show that CLedger is effective, efficient, and resilient to failures.
The current online social network landscape is characterized by competition to get larger audiences leading to massive user migrations which will determine the shape of the future Web. However, user migration phenomena have not been fully understood and their driving mechanisms are still not well identified; in particular, the behaviors of hubs and the influence they exert on their followers are unclear. In this work, we focus on these aspects by analyzing the propensity of hubs to migrate towards a new social platform as a consequence of a shocking event; and the influence they exert on the decision of their neighbors of migrating to a new platform or staying on the native one. We conducted analysis on data made available after a user migration consequence of a hard fork involving two Web3 online social networks based on the blockchains Steem and Hive. Due to the blockchain nature of these Web3 platforms, we got detailed data about social and financial interactions among the users, along with information that allowed a precise reconstruction of the context surrounding the migration. The main findings suggest that different types of hubs apply different strategies when choosing to migrate, e.g. financial hubs diversify their strategy by staying and migrating at the same time. As for hub influence, results suggest that users directly interacting with hubs tend to migrate. In general, findings on influence indicate that understanding the activity and the influence of hubs is crucial in monitoring and controlling the user migration process.
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).
Network resource sharing needs more flexible and efficient for diversified services with the rapid evolution of 5G network and IoT technology, the current sharing cannot support highly decentralized resource collaboration and sharing. In this paper, we proposed a solution to establish a sharing ecosystem by DLT, and research the relationship and activities of roles in this ecosystem. Based on these, we research the general framwork of network resource sharing based on DLT and give the scenarios and application by using it.
Blockchain is a revolutionary technique that is becoming increasingly popular for addressing a wide range of security-related issues that are controlled by both the public and private sectors. Charitable organizations are showing an increasing interest in blockchain technology. People have lost faith in charities as a matter of fact of the transactions’ lack of clarity involving donations, which prevents donors from knowing whether their contributions are being used effectively. This paper suggests a decentralized blockchain-based Alumni Network Donation App: AlumNet that will deliver to the target group total transparency, integrity, and access directly. The alumni network is willing to support any purpose, including projects, conferences, etc., through this platform. It is focused upon the blockchain of Ethereum. The smart contract consists of token creation, issue and transfer functions and initially some tokens are provided by the smart contract. This is a totally decentralized system and the donations made are stored onto the blockchain.
Blockchain and distributed ledger technology started as a decentralized infrastructure to enable and manage digital currency like Bitcoin without relying on a central authority. One of the attractive features provided by blockchain technology is its append-only “immutability” feature, which means the stored data cannot be modified or manipulated by any means once it is validated in the blockchain ledger. Such immutability helps traceability, auditing, and non-repudiation, which builds decentralized trust among un-trusted parties. Despite that, immutability if misused could lead to the permanent existence of sensitive information and misinformation in the blockchain. Incidents like broadcasting illegal content have already taken their place in blockchain systems. Such incidents call for prompt solutions for mitigation. One emerging research theme, “redactable distributed ledgers” such as redactable blockchain provides approaches for modifying ledgers with certain controllability. This article aims to survey the current research landscape about redactable distributed ledgers. We will first describe the motivations behind redactable distributed ledgers. Compared to other relevant surveys, we comprehensively summarized and briefly explained the underlying technologies for supporting redactable distributed ledgers. We mainly focused on chameleon hash-based redactable blockchain structure and classifications, with detailed comparisons and illustrations. Further, we tackled new distributed ledger structures, including the new state-of-the-art block matrix structure. Furthermore, new applications that can be enabled by redactable distributed ledgers and future research directions are discussed in detail. This article emphasizes the motivation of utilizing the redactable distributed ledgers in several critical applications to mitigate misuse of immutability features threatening the original known design of distributed ledgers.
M. Darshan, Matthieu Amet, Gautam Srivastava, Jorge Crichigno
Blockchain technology is crucial for cutting-edge demands and aligns with the trend toward decentralized architecture. Interoperability between private and public blockchain technology can revolutionize digital record-keeping and enable automation. Traditional database systems saw major developments when application programming interfaces (APIs) and data were used across centralized entities. For blockchain technology, the natural evolution would be to facilitate communication and data exchange between private and public blockchain technologies, potentially revolutionizing digital record-keeping for future automation. Our research tests this interoperability in real-world scenarios and explores smart city elements and use-cases for application in the next generation of blockchain systems.
Blockchain mandates that every node store the whole chain’s history in order to address trust issues in the network. And the storage requirement becomes extremely high, severely affecting the chain’s scalability. To solve such a problem, many optimizations of storage have been proposed. In this paper, existing ways of blockchain storage scalability are described in two categories: off-chain and on-chain. The off-chain way is combined with various distributed and nondistributed storage systems. And on-chain is optimized by changing its block structure, storage rules, or technology. Blockchain technology with scalable storage has been applied in the medical industry. We assess and contrast the methods’ latency, security, and cost. And we point out the problems and challenges of the existing approaches and give an outlook on the future.
Tomas Rafaj, Lukas Mastilak, Kristián Košťál, Ivan Kotuliak
Decentralized finance (DeFi) and blockchain-based gaming platforms are rapidly gaining popularity in the digital world. However, the high gas fees associated with on-chain transactions make it difficult to use these platforms for mass adoption. In this paper, we propose a DeFi gaming platform that leverages the benefits of layer 2 solutions to reduce gas fees and improve user experience. Our platform utilizes state channels, where players can interact with each other without the need for on-chain transactions. Our platform's architecture and smart contracts are designed to ensure security, transparency, and fairness. We demonstrate the feasibility and effectiveness of our platform through several test scenarios. In addition, we implement two approaches to validate the game results for different games. Our results show that using a layer 2 solution significantly reduces gas fees, making DeFi gaming accessible to a wider audience. Our proposed platform can potentially revolutionize the gaming industry by providing a seamless, decentralized, and rewarding gaming experience to users.
Cyril Kunjumon, Aditya Mutharia, Salemula Shareef, M S Suchithra
Blockchain Technology has been increasing in popularity in recent times due to its decentralized nature, immutability, transparency, high security and transparency. Several private and public organisations have been using it to develop new and innovative projects like cryptocurrency, NFTs, Metaverse, etc., and also to upgrade and improve old technologies like supply chains in agriculture and government voting systems. Land Registration is one such sector that can be upgraded using blockchain because in the current system there are a lot of middlemen involved and data is centralized and not secure, these things make the current system vulnerable to frauds and corruption. In this paper we have proposed a new implementation for the existing land registration system in the country that uses Non-Fungible tokens in the blockchain to represent a property and a sidechain like IPFS for storing its data in a decentralized manner. With our implementation we can overcome the flaws in the old system and make land registration secure, transparent and trustless. Here by "trustless" we mean that users do not have to trust any centralized authority or intermediary to verify transactions or maintain the integrity of the system. Instead, trust is placed in the system’s consensus mechanism and cryptographic protocols.
Hoai Luan Pham, Thi Hong Tran, Vu Trung Duong Le, Yasuhiko Nakashima
This article proposes a flexible and scalable BLAKE/BLAKE2 coprocessor aiming for high flexibility, high performance, and low power for blockchain-based IoT applications.
Blockchain systems must be secure and offer high performance. These systems rely on transaction broadcast mechanisms to provide both of these features. Unfortunately, in today’s systems, the broadcast mechanisms are highly inefficient.We present Mercury, a new transaction broadcast protocol designed for high performance blockchains. Mercury shortens the transaction propagation delay using two techniques: a virtual coordinate system and an early outburst strategy. Simulation results show that Mercury outperforms prior propagation schemes and decreases overall propagation latency by up to 44%. When implemented in Conflux, an open-source high-throughput blockchain system, Mercury reduces transaction propagation latency by over 50% with less than 5% bandwidth overhead.
Sharding is an effective technique to improve the scalability of blockchain. It splits nodes into multiple groups so that they can process transactions in parallel. To achieve higher parallelism and concurrency at large scales, it is desirable to maintain a large number of small shards. However, simply configuring small shards easily results in a higher fraction of malicious nodes inside shards, causing shard corruption and compromising system security. Existing sharding techniques hence demand large shards, at the expense of limited concurrency. To address this limitation, we propose CoChain: a blockchain sharding system that can securely configure small shards for enhanced concurrency. CoChain allows some shards to be corrupted. For security, each shard is monitored by multiple other shards. The latter reach a cross-shard Consensus on the Consensus results of their monitored shard. Once a corrupted shard is found, its subsequent consensus will be taken over by another shard, hence recovering the system. Via Consensus on Consensus, CoChain allows the existence of shards with more fraction of malicious nodes (<2/3) while securing the system, thus reducing the shard size safely. We implement CoChain based on Harmony and conduct extensive experiments. Compared with Harmony, CoChain achieves 35x throughput gain with 6,000+ nodes.
Peer-to-Peer (P2P) energy trading has the potential to create a more efficient and sustainable electricity market. It can relieve the load on the power grid during peak usage periods. However, such a P2P energy market is decentralized and vulnerable to numerous cyber attacks. Decentralized blockchain technology has been proposed to solve these problems. The consensus mechanism is the core of blockchain. It determines the effectiveness and safety of blockchain for energy trading. However, consensus mechanisms applied to energy trading today are traditional consensus. Due to their high latency and significant computational power, they cannot be directly implemented in P2P energy trading. Therefore, we propose a novel Block Alliance Consensus (BAC) mechanism. The BAC breaks through the blockchain impossible triangle in the energy trading scenario by reasonably pursuing decentralization. We achieve infinite scalability via sharding. Within each shard, we substitute the Hashgraph for conventional methods to further improve the throughput and transaction speed. We design a cross-shard method for transactions between different shards. We implement the energy trading blockchain (ETB) and BAC consensus mechanism on the Hyperledger Fabric platform. The experiments show that our ETB is not limited to the impossibility triangle like other consensus. Our BAC mechanism achieves infinite scalability while ensuring high levels of security.