Blockchain is considered one of the most disruptive technologies of our time and in the last 2 decades andhas drawn attention from research and industrial communities. Blockchain is basically a distributed ledger with immutable records, mostly utilized to perform the transactions across various nodes after achieving the mutual consensus between all the associated nodes. The consensus protocol is a core component of Blockchain technology, playing a vital role in Blockchain’s success, global emergence, and disruption capability.Many consensus protocols such as PoW, PoS, PoET, etc. have been proposed to make Blockchain more efficient to meet real-time application requirements. However, these protocols have their respective limitations of low throughput and high latency and sacrifice on scalability.These limitations have motivated this research team to introduce a novel review-based consensus protocol called Proof-of-Review, which is aimed to establish an efficient, reliable, and scalable Blockchain. The “review” in the proposed protocol is referring to the community trust on a node, which is entirely depending on the node’s previous behavior within the network which includes the previous transactions and interaction with other nodes. Those reviews eventually become the trust value gained by the node. The more positive the reviews the more trustworthyis the nodeto be considered in the network and vice versa. The most trustworthy node is selected to become the round leader and allows to publish a new block. The architecture of the proposed protocol is based on two parallel chains i.e. Transaction Chain and Review Chain. Both chains are linked to each other. The transaction chain stores the transaction whereas the review chain will store the reviews and be analyzed with an NLP algorithm to find the round leader for the next round.
Ammar Riadh Kairaldeen, Nor Fadzilah Abdullah, Asma Abu-Samah, Rosdiadee Nordin
Data security is a major issue for smart home networks. Yet, different existing tools and techniques have not been proven highly effective for home networks’ data security. Blockchain is a promising technology because of the distributed computing infrastructure network that makes it difficult for hackers to intrude into the systems through the use of cryptographic signatures and smart contracts. In this paper, an architecture for smart home networks that could guarantee data integrity, robust security, and the ability to protect the validity of the blockchain transactions has been investigated. The system model is tested using various sizes of realistic datasets (30, 3 k, and 30 k to represent a small, medium, and large number of transactions, respectively). Four different consensus algorithms were considered, the conventional schemes concatenated hash transactions (CHT) and Merkle hash tree (MHT), as well as the newly proposed odd and even modified MHT (O&E MHT) and modified MHT (MMHT). Moreover, 15 hash functions were also examined and compared to understand the effects of each consensus algorithms on the data integrity verification check execution time and the time optimization provided by the proposed MMHT algorithm. The results show that even though the CHT algorithm gives the lowest execution time, it is impractical for a blockchain implementation due to the requirement to copy the entire blockchain ledger in real time. Meanwhile, the O&E MHT does not give any tangible benefit in the execution time. However, the proposed MMHT offers a minimum of 30% gain in time optimization than the conventional MHT algorithm typically used in blockchains. This work shows that the proposed MMHT consensus algorithm not only can identify malicious codes but has an improved data integrity check performance in smart homes, all while ensuring network stability.
Sending bulk e-mail is commercially cheap and technically easy, making it profitable for spammers, even if a tiny percentage of recipients falls for the attacks or turn into customers. Some researchers have proposed making e-mail paid so that sending bulk e-mail becomes expensive, making spamming unprofitable and a futile exercise unless many victims respond to spam. On the other hand, the small sending fee is negligible for legitimate e-mail users. Making e-mail paid is a challenging task if implemented using a conventional payment system or developing new cryptocurrencies. Traditional payment systems are challenging to integrate with e-mail systems, and new cryptocurrencies will have challenges in adoption by users on the required scale. This work proposes using cryptocurrency payments to make e-mail senders pay for sending an e-mail without creating a new cryptocurrency or a new blockchain. In the proposed system, the recipients of the e-mail can collect the payments and use the collected revenues to send e-mail messages or even sell them on an exchange. The proposed solution has been implemented using Ropsten, an Ethereum Test Network and tested using enhanced E-mail Client and Server software.
Daniel Mago Vistro, Muhammad Shoaib Farooq, Attique Ur Rehman, Saroosh Malik
Blockchain emerges as a potential platform aim of providing efficient and robust infrastructure and the centre of the blockchain is the consensus protocol feature that shows the working of distributed ledger technology named the blockchain. However, existing blockchain systems do not satisfy the requirement of the transaction in pragmatic use due to their limited capacity. While several new ideas were suggested by experts as they faced either decentralization or security concerns. Although several scientists are working on the improvement of the new quantum-resistant, faulttolerant protocol, resource-efficient, and others focus on the development of multiple protocol versions, better adapted for particular use cases. Many researcher-made their own protocol to secure their work, instead of using traditional protocols. The paper represents a systematic literature review by accompanying a survey of blockchain technologies and their current utilization in different application domains in the IT industry. In this article, we first describe some previous and current consensus protocols of blockchain with the help of taxonomy which includes types and variants of protocols. Secondly, we have selected the most used protocols used up till now and write a comparative analysis with systematic review to find out which approach is the best suitable to use Lastly, we have analysed the strength and weaknesses of existing and previous protocols.
The sixth generation (6G) of wireless cellular networks is expected to incorporate the latest developments in network infrastructure and emerging advances in technology. In the age of 6G, edge caching technology will evolve towards intelligence, dynamics, and security. However, the security problems of edge caching, including data tampering and eavesdropping, are seldomly considered in most literatures. In this paper, we consider the two-hop edge caching where the blockchain and physical layer security technologies are adopted to prevent data from being tampered with and eavesdropped. We design blockchain-based framework to guarantee the reliability of important data such as the frequency of contents and jointly optimize content caching probability and redundancy rate to maximize the secure transmission probability. Extensive simulation shows that our optimization scheme can significantly improve the secure transmission probability of edge cache network, whether facing the threat of independent eavesdropping or joint eavesdropping.
In recent years Fifth Generation (5G) technology is the most recent advancement in a wireless communication network. There is the advent of using the 5G with diverse data structures. The Blockchain (BC) has become an approving adoption for decentralized, peer-to-peer, distributed transparent ledger systems with a diverse data structure. The use of 5G with BC is an emerging trend in communication technology. The elasticity of 5G with BC enables many applications to reciprocity information molds it a fast, transparent, consequential, and safe for transportation of data in this smart era. Green computing (GC) is presently the intense optimistic tactic for the integration of smart technology in a diverse and distributed world of power consumption. This Systematic Mapping Study (SMS) has been analyzed by cautiously elected publications between 2016 and 2020 in well-putative venus. This study analyzed the advanced research on power consumption solutions for BC-based 5G communication, Moreover, a taxonomy of 5G based on green BC and GC in various areas is presented. Furthermore, Green energy renewable communication (GERC) problems are being observed in this research by integrating three discrete technologies such as 5G with green BC and GC also along with smart systems. Lastly, the research gaps had been bestowed to render future directions for the researchers in 5G with green BC and GC as the solution for rechargeable data packets.
Blockchain technology has advanced rapidly in recent years and is now widely used in a variety of fields. Blockchain appears to be one of the best solutions for managing massive heterogeneous devices while achieving advanced data security and data reputation, particularly in the field of large-scale IoT (Internet of Things) networks. Despite the numerous advantages, there are still challenges while deploying IoT applications on blockchain systems due to the limited storage, power, and computing capability of IoT devices, and some of these problems are caused by the consensus algorithm, which plays a significant role in blockchain systems by ensuring overall system reliability and robustness. Nonetheless, most existing consensus algorithms are prone to poor node reliability, low transaction per second (TPS) rates, and scalability issues. Aiming at some critical problems in the existing consensus algorithms, this paper proposes the Efficient Byzantine Reputation-based Consensus (EBRC) mechanism to resolve the issues raised above. In comparison to traditional algorithms, we reinvented ways to evaluate node reliability and robustness and manage active nodes. Our experiments show that the EBRC algorithm has lower consensus delay, higher throughput, improved security, and lower verification costs. It offers new reference ideas for solving the Internet of Things+blockchain+Internet court construction problem.
Arvind W. Kiwelekar, Pramod Patil, Laxman D. Netak, Sanjay U. Waikar
Fog computing is a paradigm for distributed computing that enables sharing of resources such as computing, storage and network services. Unlike cloud computing, fog computing platforms primarily support {\em non-functional properties} such as location awareness, mobility and reduced latency. This emerging paradigm has many potential applications in domains such as smart grids, smart cities, and transport management. Most of these domains collect and monitor personal information through edge devices to offer personalized services. A {\em centralized} server either at the level of cloud or fog, has been found ineffective to provide a high degree of security and privacy-preserving services. Blockchain technology supports the development of {\em decentralized} applications designed around the principles of immutability, cryptography, consistency preserving consensus protocols and smart contracts. Hence blockchain technology has emerged as a preferred technology in recent times to build trustworthy distributed applications. The chapter describes the potential of blockchain technology to realize security services such as authentication, secured communication, availability, privacy and trust management to support the development of dependable fog services.
A fundamental open question for oracles in blockchain environments is a determination of the amount of trust to be placed in the oracle. Oracles serve as intermediaries between a trusted blockchain environment and the untrusted external environment from where the oracles fetch data. As such, it is important to understand the uncertainty introduced by the oracle in the trusted blockchain environment and the implications of this uncertainty on blockchain performance. This paper develops a model for commoditization of trust. The model provides for dynamic trust environments that incorporates oracle selfishness. The work also considers the equilibrium behavior for the demand and supply for trust and introduces elastic incentives for increasing the trust. These results are used to determine optimum size of the network that can be served by an oracle with varying degrees of selfishness. Key consequences and challenges of incorporating oracles in trusted distributed ledger environments are presented.
As the typical peer-to-peer distributed networks, blockchain systems require each node to copy a complete transaction database, so as to ensure new transactions can by verified independently. In a blockchain system (e.g., bitcoin system), the node does not rely on any central organization, and every node keeps an entire copy of the transaction database. However, this feature determines that the size of blockchain transaction database is growing rapidly. Therefore, with the continuous system operations, the node memory also needs to be expanded to support the system running. Especially in the big data era, the increasing network traffic will lead to faster transaction growth rate. This paper analyzes blockchain transaction databases and proposes a storage optimization scheme. The proposed scheme divides blockchain transaction database into cold zone and hot zone using expiration recognition method based on Least Recently Used (LRU) algorithm. It can achieve storage optimization by moving unspent transaction outputs outside the in-memory transaction databases. We present the theoretical analysis on the optimization method to validate the effectiveness. Extensive experiments show our proposed method outperforms the current mechanism for the blockchain transaction databases.
The deployment of small-scale renewable energy sources will transform the management of energy grids towards more decentralized solutions in which the prosumers will have a more active role. Regulatory and market barriers are driving the implementation of virtual aggregation models in which the small-scale prosumers work together on a larger scale to gain benefits that could not be obtained on an individual basis. In this paper, we propose to use public blockchain and self-enforcing smart contracts to construct Virtual Power Plants (VPPs) of prosumers to provide energy services. A model has been defined for capturing the prosumer level constraints in terms of available energy profiles and energy service requirements enabling their optimal aggregation in hierarchical structures. A lightweight decentralized solution for VPPs construction is implemented using smart contracts enabling its efficient running on the public blockchain. Smart contracts are encoding the model constraints and are defining functionalities for prosumers to initiate or join a VPP implementing the complete chain of Offer-Operate-Measure-Remunerate actions. The VPP will be managed on top of a distributed ledger technology offering decentralized functionality for tracking and validating the delivery of energy based on the blockchain transactions and for energy and financial settlement, the remuneration being done according to the amount of energy provided by individual prosumers. Experimental results show that the proposed solution runs successfully on the public blockchain with good execution time and can address Balancing Responsible Party requests for additional generation. The overhead in terms of gas consumption and transactional throughput stays within reasonable boundaries.
Blockchain has been practiced in crypto-currencies and cross-border banking settlement. However, no clear evidence that a distributed ledger network (or Blockchain) is built within domestic payment systems, although many experts believe that Blockchain has wide applicability in various industries and disciplines. As the author’s best knowledge, no one has published a clear architecture and a feasible framework for a Blockchain-based banking network. Thus, “how Blockchain can be implemented in domestic banking systems” is a big challenge. The most important contribution of this work is to give a feasible and viable framework resolving that problem. The author investigates a Blockchain-based payment framework, more explicitly, a decentralized banking architecture running on the top of existing banking cores. The Blockchain network has two tiers: master nodes (block generators) and normal nodes (validators). The consensus mechanism is introduced as a composition of Proof of Stake, Proof of Reputation and/or practical Byzantine Fault Tolerance. In addition, nomination and approval mechanisms are added to the governance to enhance legal compliance and compatibility with real Fintech space. Some qualitative analysis is provided to show that the proposed Blockchain banking framework offers better security, scalability and decentralization, while easily adapt with different national regulation environments, among other Blockchains. In the application aspects, the framework is implementable and deployable for decentralized payment network and smartcontract infrastructure for domestic markets, then enable a complete and unified digitized space for cloud banking and financial services.
Blockchain consensus, which enables nodes on a peer-to-peer network to agree on the same ledger history, is the core element of blockchain systems. In many blockchain systems, a node chosen as a block proposer, in accordance with the consensus protocol, generates a block, and each node chooses a chain to extend by a fork-choice rule. This study introduces saving attacks, a new kind of attack that prevents nodes from reaching a consensus. In saving attacks, the adversary “saves” its rights to propose blocks during a temporal consensus failure and utilizes them later to cause another consensus failure. As a result, the blockchain suffers from poor performance and high latency to block finalization. We study the effect of saving attacks on various fork-choice rules, including those that Ethereum 2.0 plans to employ.We simulate saving attacks on the longest-chain rule, Greedy Heaviest-Observed Sub-Tree (GHOST), latest-message-driven (LMD) GHOST, and fresh-message-driven (FMD) GHOST.We show that the saving attack has a very large negative impact on the consensus. For example, we observe that under a certain condition, an adversary with 30% of the total stake that has saved its blocks for 32 minutes succeeds in preventing a consensus against LMD GHOST for 83 minutes in the context of Ethereum 2.0. We also show that FMD GHOST decreases the attack duration to approximately 6.4 minutes under the same conditions. Our results are applicable to all slot-based proof-of-stake blockchains, not just Ethereum 2.0.