In today’s world, people need tremendous improvement in each aspect of life and they saw so many changes that literally make their life much more simplistic. People need to access and exchange so many data continuously, and that is the concept of cloud computing. In this area, so many advancements happen, and that leads to edge computing. With the help of this, we can access with limited amounts of time and also with fewer errors. Blockchain technology, on the other hand, has also been polar in developing decentralized applications and pushing industries or sectors such as agriculture, finance, transport, manufacturing, logistics, etc., to use blockchain or distributed ledger technology to provide end users with trusted, safe services. When blockchain technology (integration of edge computing and blockchain) is used to protect data over edge or cloud computing, we may require a sufficient number of securities, power backups, regulation, standards, etc. This chapter therefore addresses numerous subjects of interest, such as the probability of risks, research opportunities (including existing research gaps), and challenges faced during the integration of blockchain with edge computing (with the perspective of the smart era).
Lucian Trestioreanu, Cristina Nita-Rotaru, Aanchal Malhotra, Radu State
Payment systems are a critical component of everyday life in our society. While in many situations payments are still slow, opaque, siloed, expensive or even fail, users expect them to be fast, transparent, cheap, reliable and global. Recent technologies such as distributed ledgers create opportunities for near-real-time, cheaper and more transparent payments. However, in order to achieve a global payment system, payments should be possible not only within one ledger, but also across different ledgers and geographies. In this paper we propose Secure Payments with Overlay Networks (SPON), a service that enables global payments across multiple ledgers by combining the transaction exchange provided by the Interledger protocol with an intrusion-tolerant overlay of relay nodes to achieve (1) improved payment latency, (2) fault tolerance to benign failures such as node failures and network partitions, and (3) resilience to BGP hijacking attacks. We discuss the design goals and present an implementation based on the Interledger protocol and Spines overlay network. We analyze the resilience of SPON and demonstrate through experimental evaluation that it is able to improve payment latency, recover from path outages, withstand network partition attacks, and disseminate payments fairly across multiple ledgers. We also show how SPON can be deployed to make the communication between different ledgers resilient to BGP hijacking attacks.
Xiaogang Xing, Yuling Chen, Tao Li, Yang Xin · 5 authors
Abstract Blockchain technology has the characteristics of decentralization and tamper resistance, which can store data safely and reduce the cost of trust effectively. However, the existing blockchain system has weak performance in data management, and only supports traversal queries with transaction hashes as keywords. The query method based on the account transaction trace chain (ATTC) improves the query efficiency of historical transactions of the account. However, the efficiency of querying accounts with longer transaction chains has not been effectively improved. Given the inefficiency and single method of the ATTC index in the query, we propose a subchain-based account transaction chain (SCATC) index structure. First, the account transaction chain is divided into subchains, and the last block of each subchain is connected by a hash pointer. The block-by-block query mode in ATTC is converted to the subchain-by-subchain query mode, which shortens the query path. Multiple transactions of the same account in the same block are merged and stored, which simplifies the construction cost of the index and saves storage resources. then, the construction algorithm and query algorithm is given for the SCATC index structure. Simulation analysis shows that the SCATC index structure significantly improves query efficiency.
Qianyun Gong, Chengjin Zhou, Le Qi, Jianbin Li · 6 authors
The payment channel networks (PCNs), as the main method of blockchain off-chain expansion, have received extensive attention in recent years. Using the PCNs, two unconnected parties in a transaction can forward payments through existing payment channels of other nodes, which dramatically reduces interactions with the blockchain. But in large-scale dynamic PCNs, the routing mechanism is a challenge. Existing PCNs routing algorithms have some limitations. The landmark routing destroys the decentralization of blockchain. The static routing requires nodes having a global view and ultra-high computing power, which can not be applied to light nodes. We propose VEIN, a dynamic multi-path source routing algorithm, which is suitable for not only full nodes but also light nodes. We present an ingenious routing protocol, a modified max-flow algorithm to find edge-disjoint paths, and a path selection algorithm to deal with the NP-hard multi-path selection problem. Extensive experiments show that VEIN increases the transaction success ratio by 34% with the state-of-art algorithm, and realizes multiple orders of magnitude reduction in storage. In addition, we implement a prototype of VEIN on the Ethereum testnet to verify its feasibility.
Cesar E. Castellon, Swapnoneel Roy, Patrick Kreidl, Ayan Dutta · 5 authors
Blockchain-powered smart systems deployed in different industrial applications promise operational efficiencies and improved yields, while mitigating significant cybersecurity risks pertaining to the main application. Associated tradeoffs between availability and security arise at implementation, however, triggered by the additional resources (e.g., memory, computation) required by each blockchain-enabled host. This paper applies an energy-reducing algorithmic engineering technique for Merkle Tree root calculations, a principal element of blockchain computations, as a means to preserve the promised security benefits but with less compromise to system availability. Using pyRAPL, a python library to measure computational energy, we experiment with both the standard and energy-reduced implementations of the Merkle Tree for different input sizes (in bytes). Our results show up to 98% reduction in energy consumption is possible within the blockchain's Merkle Tree construction module, such reductions typically increasing with larger input sizes. The proposed energy-reducing technique is similarly applicable to other key elements of blockchain computations, potentially affording even “greener” blockchain-powered systems than implied by only the Merkle Tree results obtained thus far.
Blockchain brings many added values to modern business systems. However, Blockchain-based applications with massive IoT devices experience some limitations. The limitations are due to the linear structure and the consensus algorithms used in Blockchain that consume the participating nodes' considerable resources. In addition, IoT devices are generally with limited resources and have limited bandwidth connections. IOTA, based on Directed Acyclic Graph (DAG), is a new distributed ledger technology (DLT) for IoT devices. It proves its high scalability by providing parallel data processing. However, DAG is still not mature enough to fully replace Blockchain. In previous work, we proposed combining Blockchain and IOTA technologies to allow scalable transactions where Blockchain is employed in the backend, and Tangle is used in the frontend. This paper considers the proposed solution, focusing mainly on the connector part that intermediates both DLT technologies. The connector is a decentralized software component that supports the interaction between the DLT implicitly. The experiments' results show the flexibility to merge both DLTs using a message queuing protocol that enables smart contracts to run on the Tangle nodes and enriches the new platform with reliability and working offline features.
Ethereum as one of the largest blockchain systems plays an important role in the distributed ledger, database systems, etc. As more and more blocks are mined, the storage burden of Ethereum is significantly increased. The current Ethereum system uniformly transforms all its data into key-value (KV) items and stores them to the underlying Log-Structure Merged tree (LSM-tree) storage engine ignoring the software semantics. Consequently, it not only exacerbates the write amplification effect of the storage engine but also hurts the performance of Ethereum. In this paper, we proposed a new Ethereum-aware storage model called Block-LSM, which significantly improves the data synchronization of the Ethereum system. Specifically, we first design a shared prefix scheme to transform Ethereum data into ordered KV pairs to alleviate the key range overlaps of different levels in the underlying LSM-tree based storage engine. Moreover, we propose to maintain several semantic-orientated memory buffers to isolate different kinds of Ethereum data. To save space overhead, Block-LSM further aggregates multiple blocks into a group and assigns the same prefix to all KV items from the same block group. Finally, we implement Block-LSM in the real Ethereum environment and conduct a series of experiments. The evaluation results show that Block-LSM significantly reduces up to 3.7× storage write amplification and increases throughput by 3× compared with the original Ethereum design.
Blockchains are append-only data structures, meaning their size increases steadily. As of March 2021, new nodes connecting to the Bitcoin blockchain already need to synchronize and validate more than 330 GB of data. Already now, this is an issue for resource-constrained thin clients who lack the required download, storage, or computing capacities to achieve this. In future, this issue will become even more relevant when blockchain technology is applied to new domains like the Internet of Things (IoT). We propose a new blockchain architecture that addresses this issue. Our proposal relies on incremental snapshot blocks that allow new and occasionally used clients to synchronize with the current state of the blockchain efficiently. The snapshot blocks form a second linked blockchain and are secured by the blockchain consensus algorithm. In this paper, we describe the proposed architecture in detail and evaluate its storage-saving potential using the Bitcoin blockchain. The evaluations performed show that our design can reduce the volume of data that needs to be downloaded and stored by up to 98%, thus facilitating secure blockchain-based applications also on resource-constrained thin clients like smartphones, netbooks, or IoT devices.
Oct 1, 2021·2021 IEEE SmartWorld, Ubiquitous Intelligence & Computing, Advanced & Trusted Computing, Scalable Computing & Communications, Internet of People and Smart City Innovation (SmartWorld/SCALCOM/UIC/ATC/IOP/SCI)
Nazmus Saquib, Fatih Bakir, Chandra Krintz, Rich Wolski
Due to the proliferation of IoT and the popularity of smart contracts mediated by blockchain, smart home systems have become capable of providing privacy and security to their occupants. In blockchain-based home automation systems, business logic is handled by smart contracts securely. However, a blockchain-based solution is inherently resource-intensive, making it unsuitable for resource-constrained IoT devices. Moreover, time-sensitive actions are complex to perform in a blockchainbased solution due to the time required to mine a block. In this work, we propose a blockchain-independent smart contract infrastructure suitable for resource-constrained IoT devices. Our proposed method is also capable of executing time-sensitive business logic. As an example of an end-to-end application, we describe a smart camera system using our proposed method, compare this system with an existing blockchain-based solution, and present an empirical evaluation of their performance.
With the development of blockchain, various blockchain-based applications emerged. Of which Bitcoin and Ethereum are the most representative and popular blockchain applications. Therefore, it is important to compare Bitcoin with Ethereum and infer their developing trends. In the paper, we compare Bitcoin and Ethereum from different perspectives, including consensus algorithm, transaction cost, extension, and security. Comparative results demonstrate that Ethereum is better than Bitcoin on extension and transaction mechanism. Also, based on the results, we discuss about the essential development trend about blockchain applications. In the future, blockchain applications will be a platform which can provide more functions than digital currencies.
Kai Li, Yuzhe Tang, Jiaqi Chen, Yibo Wang · 5 authors
Ethereum relies on a peer-to-peer overlay network to propagate information. The knowledge of Ethereum network topology holds the key to understanding Ethereum's security, availability, and user anonymity. From a measurement perspective, an Ethereum network's topology is routing-table information hidden inside individual Ethereum nodes, measuring which poses challenges and remains an open research problem in the existing literature. This paper presents TopoShot, a new method uniquely repurposing Ethereum's transaction replacement/eviction policies for topology measurement. TopoShot can be configured to support Geth, Parity, and other major Ethereum clients. As validated on local nodes, TopoShot achieves 100% measurement precision and high recall 88% - 97%. To efficiently measure the large Ethereum networks in the wild, we propose a non-trivial schedule to run pair-wise measurements in parallel. To enable ethical measurement on Ethereum mainnet, we propose workload-adaptive configurations of TopoShot to minimize the service interruption to target nodes/network. We systematically measure a variety of Ethereum networks and obtain new knowledge including the full-network topology in major testnets (Ropsten, Rinkeby and Goerli) and critical sub-network topology in the mainnet. The results on testnets show interesting graph-theoretic properties, such as all testnets exhibit graph modularity significantly lower than random graphs, implying resilience to network partitions. The mainnet results show biased neighbor selection strategies adopted by critical Ethereum services such as mining pools and transaction relays, implying a degree of centralization in real Ethereum networks.
Recently, blockchain has been evolving rapidly with new innovations, coins, and use cases every day. The platform is getting more congested due to the increase of interest and mainstream adoption, and because most of this activity is on the widely used Ethereum blockchain. This also further increases the costs of using the platform, as the gas prices become higher. Smart contracts are deployed on the Ethereum blockchain and the high usage of these smart contracts is one of the main reasons behind the congestion. We propose a new scheme using sidechains and a middleware to reduce the workload for certain smart contracts, which allows the execution of smart contract transactions in parallel through sidechains. In this way, the sidechains could be leveraged to decrease the congestion on the main blockchain and increase the rate of transactions per second. Furthermore, the sidechains could have their settings, like block time and block gas limit, adjusted to give more optimal results. We implemented a modified version of the ballot contract from the solidity documentation, and our results demonstrated that through the use of two sidechains, the transactions processed per second could be increased from 1.8× to 13.0×, depending on the sidechains settings.
Recent years have witnessed an increasing interest in the blockchain technology, and many blockchain-based applications have been developed to take advantage of its decentralization, transparency, fault tolerance, and strong security. In the field of smart grids, a plethora of proposals have emerged to utilize blockchain for augmenting intelligent energy management, energy trading, security and privacy protection, microgrid management, and energy vehicles. Compared with traditional centralized approaches, blockchain-based solutions are able to exploit the advantages of blockchain to realize better functionality in smart grids. However, the blockchain technology itself has its disadvantages in low processing throughput and weak privacy protection. Therefore, it is of paramount importance to study how to integrate blockchain with smart grids in a more effective way so that the advantages of blockchain can be maximized and its disadvantages can be avoided. This article surveys the state-of-the-art solutions aiming to integrate the emergent blockchain technology with smart grids. The goal of this survey is to discuss the necessity of applying blockchain in different components of smart grids, identify the challenges encountered by current solutions, and highlight the frameworks and techniques used to integrate blockchain with smart grids. We also present thorough comparison studies among blockchain-based solutions for smart grids from different perspectives, with the aim to provide insights on integrating blockchain with smart grids for different smart grid management tasks. Finally, we list the current projects and initiatives demonstrating the current effort from the practice side. Additionally, we draw attention to open problems that have not yet been tackled by existing solutions, and point out possible future research directions.
present, we are in the world of digital revolution. Use of smartphones and internet accelerated due to the impact of the novel Covid-19 virus. The whole world started to turn digital. The industrialization of Internet of Things (IoT) enables more devices to connect and communicate which leads to many data transfer transactions. The architecture of IoT is centralized. The distributed and decentralized architecture of Blockchain can be used to provide secure and scalable transactions of IoT devices. Blockchain is a distributed ledger technology, which provides secure data transactions that cannot be tampered and altered. In this paper, we provide advantages and challenges of integrating IoT and Blockchain. We also provide different architectures and algorithms proposed by researchers to provide secure data transactions. We shall also shed light on the future research directions of integrating Blockchain and IoT.
Integrating blockchain into software solutions is not straightforward as it requires sophisticated architectural design to connect and orchestrate centralized elements, such as backend logic, with decentralized elements, such as blockchain ledgers and smart contracts. We systematically explore this design space and possible architectural solution approaches. More specifically, we provide architectural blue prints for applications with different degrees of decentralization, describe conceptional components as well as possible relations between them. Our research shows that an event-driven architecture incorporating a messaging framework, tethered to dedicated components for handling blockchain state-changing and state-collecting operations, is a prevalent approach for choreographing blockchain-dependent business logic in blockchain-based applications.
Mobile ad-hoc network (MANET) is an infrastructure-less extended scenario of blockchain radio access network (B-RAN); meanwhile, the decentralization of B-RAN befits MANETs. In the framework of B-RAN, we propose a blockchain-based multi-hop routing protocol, namely Data Broker, for non-cooperative MANETs. To incentivize the collaboration among selfish peers, we record the identity information of participating brokers on a ledger list. However, blockchain cannot guarantee the integrity of such a routing ledger directly. Therefore, we design a ledger safeguard mechanism, along with reward policies, to avoid the ledger list being tampered with or modified by dishonest brokers. The experimental results show that the proposed Data Broker can significantly improve the network performance of non-cooperative MANETs regarding latency and loss rate.
Bitcoin first proposed the Nakamoto consensus that applies proof of work into the blockchain structure to build a trustless append-only ledger. The Nakamoto consensus solves the distributed consistency problem in the public network but wastes too much computing power. Instead of consuming computing resources, many improved consensus schemes address this problem by leveraging miners’ storage resources. However, these schemes fail to let miners store data constantly and usually rely on a dealer to assign data, which is hard to build a reliable decentralized storage system. In this article, we first design a variant consensus algorithm named Proof of Continuous Work (PoCW) with a storage-related incentive mechanism. Miners can accumulate mining advantage by continuously submitting proofs of storage. Then, we present a hash ring-based data allocation algorithm using the blockchain’s state. Combined with both of them, we build a reliable blockchain-based storage system without relying on any third parties. The theoretical analysis and simulation results demonstrate that the proposed system has higher reliability than those existing systems, and we also give practical suggestions about system parameters. Finally, we discuss additional benefits that our system brings.
Lei Wu, Yki Kortesniemi, Dmitrij Lagutin, Maryam Pahlevan
In recent years, multiple distributed ledger technologies with different strengths and weaknesses have been introduced. This makes them better suited for different use cases, but it also makes interactions between the ledgers more difficult. Interledger technologies try to bridge this gap, but often suffer from obvious limitations: a large portion of the solutions addresses only value exchanges or transfers, others have restrictive assumptions about the ledgers, and some require separate relaying blockchains. This paper introduces the Flexible Interledger Bridge (FIB) design that supports a wide range of use cases and ledger types without requiring any changes to the ledgers themselves. An evaluation of the reference implementation shows it to be a lightweight solution that enables atomic data transfers between two ledgers.
Blockchain Technology Applications and Security
Caching and Content Delivery
Innovative Microfluidic and Catalytic Techniques Innovation
Sebastian Müller, Angelo Capossele, Bartosz Kuśmierz, Vivian Lin · 9 authors
The security of any Distributed Ledger Technology (DLT) depends on the safety of the network layer. Much effort has been put into understanding the consensus layer of DLTs. However, many network layer designs seem ad-hoc and lack a careful analysis of the influence of the design decisions on the whole DLT system. We propose a salt-based automated neighbor selection protocol that shows the inherent tradeoffs of certain design decisions and allows a quantitative treatment of some network topology requirements. This example may serve as a design framework and facilitate future research. We provide a selection of results from simulations to highlight some tradeoffs in the design decisions.
The Bitcoin peer-to-peer network ensures the consensus between the different nodes responsible for the propagation of the blocks containing the validated bitcoin transactions. The quality and safety of this network are therefore particularly essential. In this work, we present a study of the public nodes that form the backbone of the Bitcoin p2p network. We analyze the results of our measurement campaign that was made following a well-defined and reproducible methodology. In particular we analyze several criteria that can affect the network resilience: distribution and security assessment of the clients' versions, churn, detection of Sybil nodes, dynamicity and popularity of peers. We also investigate the countermeasures deployed to prevent an accurate inference of the network topology and show their effectiveness.
Michał Król, Onur Ascigil, Sergi Reñé, Alberto Sonnino · 6 authors
We propose Shard Scheduler, a system for object placement and migration in account-based sharded blockchains. Our system calculates optimal placement and decides on object migrations across shards. It supports complex multi-account transactions caused by smart contracts. Placement and migration decisions made by Shard Scheduler are fully deterministic, verifiable, and can be made part of the consensus protocol. Shard Scheduler reduces the number of costly cross-shard transactions, ensures balanced load distribution and maximizes the number of processed transactions for the blockchain as a whole. To this end, it leverages a novel incentive model motivating miners to maximize the global throughput of the entire blockchain rather than the throughput of a specific shard. In our simulations, Shard Scheduler can reduce the number of costly cross-shard transactions by half while ensuring equal load and increasing throughput more than 2 fold when using 60 shards. We also implement and evaluate Shard Scheduler on Chainspace, more than doubling its throughput and reducing user-perceived latency by 70% when using 10 shards.