Seth Djanie Kotey, Eric Tutu Tchao, Abdul‐Rahman Ahmed, Andrew Selasi Agbemenu · 8 authors
Abstract Blockchain technology has been increasingly adopted over the past few years since the introduction of Bitcoin, with several blockchain architectures and solutions being proposed. Most proposed solutions have been developed in isolation, without a standard protocol or cryptographic structure to work with. This has led to the problem of interoperability, where solutions running on different blockchain platforms are unable to communicate, limiting the scope of use. With blockchains being adopted in a variety of fields such as the Internet of Things, it is expected that the problem of interoperability if not addressed quickly, will stifle technology advancement. This paper presents the current state of interoperability solutions proposed for heterogenous blockchain systems. A look is taken at interoperability solutions, not only for cryptocurrencies, but also for general data‐based use cases. Current open issues in heterogenous blockchain interoperability are presented. Additionally, some possible research directions are presented to enhance and to extend the existing blockchain interoperability solutions. It was discovered that though there are a number of proposed solutions in literature, few have seen real‐world implementation. The lack of blockchain‐specific standards has slowed the progress of interoperability. It was also realized that most of the proposed solutions are developed targeting cryptocurrency‐based applications.
Mencapai keseimbangan antara skalabilitas, keberlanjutan, dan keamanan sambil mempertahankan desentralisasi telah menjadi solusi target untuk aplikasi blockchain yang terdesentralisasi selama beberapa tahun terakhir. Beberapa pendekatan telah diusulkan oleh beberapa tim blockchain untuk mencapainya, Ethereum termasuk di antaranya. Ethereum berada di jalur peningkatan protokol utama yang disebut Ethereum 2.0 (Eth2), menerapkan Sharding dan memperkenalkan Proof-of-Stake (PoS). Karena perubahan mekanisme konsensus merupakan masalah yang rumit, peningkatan ini akan dicapai melalui fase yang berbeda, yang pertama adalah penerapan Beacon Chain. Sebagai Ethereum1, Eth2 mengandalkan jaringan peer-to-peer (p2p) terdesentralisasi untuk distribusi pesan. Hingga saat ini, ada lebih dari 17.500 node di jaringan utama Eth2 yang tersebar secara geografis. Namun, topologi yang satu ini masih belum diketahui. Dalam makalah ini, kami menyajikan hasil yang diperoleh dari analisis yang kami lakukan pada jaringan p2p Eth2. Menggambarkan topologi jaringan, kemungkinan bahaya yang disiratkan oleh yang satu ini (Cortes-Goicoechea and Bautista-Gomez, 2021).
Blockchain technology has been integrated into diverse software applications by enabling a decentralised architecture design. However, the defects of on-chain algorithmic mechanisms, and tedious disputes and debates in off-chain communities may affect the operation of blockchain systems. Accordingly, blockchain governance has received great interest for supporting the design, use, and maintenance of blockchain systems, hence improving the overall trustworthiness. Although much effort has been put into this research topic, there is a distinct lack of consideration for blockchain governance from the perspective of software architecture design. In this study, we propose a pattern-oriented reference architecture for governance-driven blockchain systems, which can provide guidance for future blockchain architecture design. We design the reference architecture based on an extensive review of architectural patterns for blockchain governance in academic literature and industry implementation. The reference architecture consists of four layers. We demonstrate the components in each layer, annotating with the identified patterns. A qualitative analysis of mapping two concrete blockchain architectures, Polkadot and Quorum, on the reference architecture is conducted, to evaluate the correctness and utility of proposed reference architecture.
Smart contracts are programs whose business logic runs in a decentralized architecture named blockchain where each of the executing nodes trusts and agrees with the execution outcomes. Blockchain is an isolated execution environment, so smart contracts cannot access external data by themselves. The blockchain Oracle, or simply Oracle, is the software that allows smart contracts to interact with the outside world. In the past, a wide variety of studies have examined the oracles from various perspectives such as their implementation characteristics and their reliability. Unlike some other studies, this paper analyzes the use of Oracles through a static analysis of smart contracts. First, we analyze the source code of a corpus of over 40K smart contracts to find the most blockchain Oracles used by the Ethereum blockchain. On the basis of previous works, we examine the features of the most used blockchain Oracles in Ethereum. Lastly, we discussed our findings and the possible reasons why some blockchain oracles are more widely used than others. The purpose of this study is to shed light on how and which oracles are actually used by Ethereum smart contracts, as an alternative to other very interesting studies that analysed the blockchain oracle characteristics.
Petya Hristova Cvitic, Felix Dobslaw, Francisco Gomes de Oliveira Neto
A distributed ledger is the backbone of all blockchain solutions. It provides a shared database spreading across a network of nodes. The number of DL solutions and their implementations has grown in recent years. Besides the architectural and performance promises of thesesolutions, organizations seekingto implement DL also need to consider the overall quality of the software available and its ecosystem. Particularly, previous research has identified the need to better understand the testing and maintenance practices behind these types of technologies. This paper investigates the testing and maintenance of 18 different open-source projects that implement distributed ledgers. We perform a manual inspection of test artefacts and mine the history of commits, issues and contributors of the chosen projects to understand the landscape of testing and maintenance in these projects. Our findings suggest that unit and integration tests are present in most projects, they do not follow a holistic system testing approach. Moreover, projects rely on a small team of core contributors (5 on average). While the projects are continuously maintained, larger changes are uncommon. Our results can be used for benchmarking and pinpointing areas of improvement for the development of distributed ledgers.
Alberto Arias Maestro, Óscar Sanjuán Martínez, Ankur Teredesai, Vicente García‐Díaz
Contemporary cloud application and Edge computing orchestration systems rely on controller/worker design patterns to allocate, distribute, and manage resources. Standard solutions like Apache Mesos, Docker Swarm, and Kubernetes can span multiple zones at data centers, multiple global regions, and even consumer point of presence locations. Previous research has concluded that random network partitions cannot be avoided in these scenarios, leaving system designers to choose between consistency and availability, as defined by the CAP theorem. Controller/worker architectures guarantee configuration consistency via the employment of redundant storage systems, in most cases coordinated via consensus algorithms such as Paxos or Raft. These algorithms ensure information consistency against network failures while decreasing availability as network regions increase. Mainstream blockchain technology provides a solution to this compromise while decentralizing control via a fully distributed architecture coordinated through Byzantine-resistant consensus algorithms. This research proposes a blockchain-based decentralized architecture for cloud resource management systems. We analyze and compare the characteristics of the proposed architecture concerning the consistency, availability, and partition resistance of architectures that rely on Paxos/Raft distributed data stores. Our research demonstrates that the proposed blockchain-based decentralized architecture noticeably increases the system availability, including cases of network partitioning, without a significant impact on configuration consistency.
Muhammad Hammad, Jawaid Iqbal, Ch Anwar Ul Hassan, Saddam Hussain · 9 authors
Version control is an important component of configuration management, and most enterprise-level software uses different tools and technologies to manage the software version control such as CVS, Subversion, or Perforce. Following the success of bitcoin, the first practical application of blockchain, it is being implemented in other fields such as healthcare, supply chains, financial management, real estate, electoral systems, and so on. Blockchain’s core features include decentralization, immutability, and interminability. Most version control repositories are centralized and can be modified by external sources, implying that they are in danger of being corrupted or controlled. In this study, we present the BDA-SCV architecture for implementing a version control system in blockchain technology. Our proposed approach would replace the necessity for a centralized system, with a decentralized approach implemented in the blockchain using distributed file storage, for which we will use the InterPlanetary File System (IPFS), which is a distributed file system. The proof of authority (PoA) consensus algorithm will be used to approve the developer communicating modifications to the private blockchain network; the authority will only provide permission and will not be able to add, edit, or delete code files. For each change, a ledger block will be created with a reference to the file stored in the distributed repository. A block cannot be manipulated once it has been created. Smart contracts will be used to register developers, create blocks, and manage the repository. The suggested model is implemented using the Hyperledger Fabric network, and the developer and authorizer ends are built into the dotnet web application.
Christian Baliker, Mohamed Baza, Abdullah Alourani, Ali Alshehri · 6 authors
Financial Technology (FinTech) has expanded beyond simple mobile banking to online money transfers, crowdfunding, and managing individual investments. This reinforces the importance of ensuring security and privacy in FinTech, e.g., using Blockchain (hereafter referred to as Blockchain-based FinTech applications). In this work, we will systematically summarize recent Blockchain-based FinTech applications. As a result of the advancement of BFinTech, several novel cyberattacks have been evolved to potentially impact BFinTech functionalities. Thus, this work highlights the open research challenges and future research directions in Blockchain-based FinTech applications.
With the rapid emergence of technologies, coupling interdependent consumer electronics networks have become imperative to enable information exchange, holistic data analysis, and effective decision-making techniques. While interdependent networks can discover crucial information through intuitive understanding and efficient data-driven algorithms, it is crucial to leverage secure and effective data exchange among the underlying networks of consumer electronics. Blockchain comes into play when it requires ensuring trustless communication and data exchange among multiple interdependent networks. Blockchain interoperability is evolving and gaining widespread popularity in industry and research due to its ability to exchange data among multiple blockchains. This article presents Divide-LeapChain, a next-generation efficient and effective interoperable blockchain framework for interdependent networks of heterogeneous consumer electronics devices. The Divide-LeapChain addresses the critical issues of intra- and interblockchain communication, including spatial and temporal uncertainties in data traversal, exchange, validation, and cross-chain swaps. It promises significant drops-off in verification steps without weakening blockchain integrity, which extends the possibilities to apply blockchain applications on heterogeneous embedded consumer Internet-of-Things (IoT) devices.
Shi Peng Li, Jingwei Li, Yuxing Tang, Xiapu Luo · 12 authors
Today's blockchain systems store detailed runtime information in the format of transactions and blocks, which are valuable not only to understand the finance of blockchain-based ecosystems but also to audit the security of on-chain applications. However, exploring this blockchain “big data” is challenging due to data heterogeneity and the huge amount. Existing blockchain exploration techniques are either incomplete or inefficient, making them inapt in time-sensitive applications. This paper presents <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math>${\sf BlockExplorer}$</tex-math></inline-formula> , an efficient and flexible blockchain exploration system for Ethereum. <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math>${\sf BlockExplorer}$</tex-math></inline-formula> builds on a master-slave architecture, where the master partitions all blocks into multiple non-overlapped sets and each slave simultaneously processes Ethereum big data based on a set of blocks. <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math>${\sf BlockExplorer}$</tex-math></inline-formula> implements a transaction-based partitioning approach to address load balance among slaves, and a code instrumentation approach to acquire complete Ethereum big data. The evaluation shows that <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math>${\sf BlockExplorer}$</tex-math></inline-formula> accelerates the data acquisition performance of the state-of-the-art by 4.1×, while the workload difference among slaves is up to 18%. To demonstrate the application of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math>${\sf BlockExplorer}$</tex-math></inline-formula> , we develop three apps upon <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math>${\sf BlockExplorer}$</tex-math></inline-formula> to detect real-life attacks against Ethereum and show that our apps can detect attacks in a large range of blocks (e.g., ten million) within a short time (e.g., multiple hours).
Sanil Gandhi, Arvind W. Kiwelekar, Laxman D. Netak, Shashank Shahare
Approval processes are intra-organizational business processes designed to sanction the execution of specific administrative tasks. Purchasing essential stationery products, filing bills for acquired items, approving attendance at conferences, processing insurance claims, approving loans, and similar tasks are examples for which employees require approvals from multiple authorities within an organization. Common concerns mentioned by both the approving authority and the proposal submitter are the genuineness of the proposer and the time required for approving the proposal. This paper presents a novel Blockchain-based Approval Process System (BAPS) to establish mutual trust between the submitter and the approving authorities. The proposed system’s design, implementation, and evaluation are included in this paper. The suggested approach can shorten the time needed to obtain the permissions and increase transparency between the users and the authority. In addition, it eliminates issues such as the misplacement of papers. It stores the information in a secure and tamper-proof platform which is some of the most significant drawbacks of traditional paper-based systems.
Founded in 2017, Algorand is one of the world's first carbon-negative, public blockchains inspired by proof of stake. Algorand uses a Byzantine agreement protocol to add new blocks to the blockchain. The protocol can tolerate malicious users as long as a supermajority of the stake is controlled by non-malicious users. The protocol achieves about 100x more throughput compared to Bitcoin and can be easily scaled to millions of nodes. Despite its impressive features, Algorand lacks a reward-distribution scheme that can effectively incentivize nodes to participate in the protocol. In this work, we study the incentive issue in Algorand through the lens of game theory. We model the Algorand protocol as a Bayesian game and propose a novel reward scheme to address the incentive issue in Algorand. We derive necessary conditions to ensure that participation in the protocol is a Bayesian Nash equilibrium under our proposed reward scheme even in the presence of a malicious adversary. We also present quantitative analysis of our proposed reward scheme by applying it to two real-world deployment scenarios. We estimate the costs of running an Algorand node and simulate the protocol to measure the overheads in terms of computation, storage, and networking.
Rati Gelashvili, Alexander Spiegelman, Zhuolun Xiang, George Danezis · 8 authors
Block-STM is a parallel execution engine for smart contracts, built around the principles of Software Transactional Memory. Transactions are grouped in blocks, and every execution of the block must yield the same deterministic outcome. Block-STM further enforces that the outcome is consistent with executing transactions according to a preset order, leveraging this order to dynamically detect dependencies and avoid conflicts during speculative transaction execution. At the core of Block-STM is a novel, low-overhead collaborative scheduler of execution and validation tasks.
Manaswini Piduguralla, Saheli Chakraborty, Parwat Singh Anjana, Sathya Peri
Blockchain technology is a distributed, decentralized, and immutable ledger system. It is the platform of choice for managing smart contract transactions (SCTs). Smart contracts are self-executing codes of agreement between interested parties commonly implemented using blockchains. A block contains a set of transactions representing changes to the system and a hash of the previous block. The SCTs are executed multiple times during the block production and validation phases across the network. The execution is sequential in most blockchain technologies. In this work, we incorporate a direct acyclic graph (DAG) based parallel scheduler framework for concurrent execution of SCTs. The dependencies among a block's transactions are represented through a concurrent DAG data structure that assists in throughput optimization. We have created a DAG scheduler module that can be incorporated into blockchain platforms for concurrent execution with ease. We have also formally established the safety and liveness properties of the DAG scheduler. For evaluation, our framework is implemented in Hyperledger Sawtooth V1.2.6. The performance across multiple smart contract applications is measured for various scheduler types. Experimental analysis shows that the proposed framework achieves notable performance improvements over the parallel SCT execution frameworks.
Juan Jesús Rico-Peña, Raquel Arguedas Sanz, Carmen López-Martín
Blockchain has emerged as an innovative technology with potential to transform business management, through operational efficiency improvements. Nevertheless, several performance and vulnerability issues have been identified for the different typologies supporting the wide range of blockchain-based applications currently implemented in different domains. A variety of analytical and empirical models are being used to evaluate the issues associated with the different blockchain typologies, enabling systematic analyses of the corresponding efficiency impact, and technical or economic threats. A thorough systematic literature review of these models has been performed, followed by a detailed assessment on the way these models have been employed, and the target parameters and applications evaluated (336 research selected and analysed). We propose a co-classification of these models, allowing us to identify which ones are employed to a greater extent to address the different blockchain issues in scientific research. In a second step, a bibliometric analysis on the selected research is conducted, offering a complementary overview of the status of and trends in blockchain modelling, including the most prolific authors and leading contributing countries to the topic. The main outcome and contribution of the paper is the provision of a broad overview on how blockchain issues have been analytically tackled, through the synthesis and meta-analysis of the models used in the scientific literature since the inception of blockchain technology. The results have two main direct applications, firstly supporting novel vulnerability and performance analyses of existing blockchain applications by providing historical information on the models used so far, as well as the key parameters and typology of the blockchain-based applications evaluated. Secondly, in the implementation of new applications, by allowing the recognition of key issues identified that are associated with the different blockchain typologies and to determine the most suitable models to analyse the weaknesses and risks of the alternative designs under evaluation for these new implementations.
As the underlying technology of cryptocurrencies, blockchain has gained a lot of attention in recent years. However, the storage problem needs to be solved with the increasing number of blocks in the blockchain network. Cloud storage optimization is an effective way to solve the storage issue, which selects and stores parts of blocks to the cloud. Precisely, block selection can be described as a multiobjective optimization problem (MOP) and solved by evolutionary algorithms (EAs). To obtain well results of block selection, an improved NSGA-III algorithm based on deep Q-networks (DQN), termed NSGA-DQN, is proposed in this paper, which aims to maintain well convergence and diversity of the population. This way, a set of suitable solutions is obtained to determine the number of blocks stored to the cloud, and the storage problem can be solved effectively. To be specific, DQN creates a decision-making agent to maximize the expected reward by learning a policy that evaluates$Q$values of each action in each state. In the proposed selection mechanism, the reward values are set according to the convergence and diversity of the population, and the actions correspond to the individuals. This way, our method can determine a set of individuals that maximizes the convergence and diversity of the population. In addition, an adaptive maximum reward enhancement module (AMREM) is developed to further enhance the maximum expected reward by updating the new better reward and modifying the replay memory. We conduct the experimental study on block selection, and the results demonstrate that the proposed algorithm is superior to five state-of-the-art algorithms.
The next-generation blockchain ecosystem is expected to integrate both homogeneous and heterogeneous distributed ledgers. These systems require operations across multiple blockchains to enrich advanced functionalities for future applications. However, the development of blockchain interoperability involves much more complexity regarding the variety of underlying architectures. Guaranteeing the properties of ACID (Atomicity, Consistency, Isolation, Durability) across diverse blockchain systems remains challenging. To clear the fog, this article accordingly provides a comprehensive review of the current progress of blockchain interoperability. We explore the general principles and procedures for interoperable blockchain systems to highlight their design commons. Then, we survey practical instances and compare state-of-the-art systems to present their unique features between distinct solutions. Finally, we discuss critical challenges and point out potential research directions. We believe our work can provide an intuitive guideline for newcomers and also promote rapid development in terms of blockchain interoperability.
Pradeep Kumar, Manya Kumar, Kulvinder Singh, A. R. Tripathi
Blockchain is a development that draws in a got and circled segment to record trades. Blockchain used as digital competencies based in education fields to enhance the education in era. The advantages are enabled through the use of public-key encryption and peer-to-peer (P2P) architecture, as well as the use of public or private blockchain networks. Today, although blockchain is becoming more popular, some people are still skeptical about its long-term viability, scalability, and security. Distributed ledger technology, or blockchains, have been compared to the early days of the internet, with comments and debates regarding the technology’s potential to disrupt a variety of industries, including healthcare, government, energy, manufacturing, and, most significantly, financial services, where it is expected to be the beating heart of finance and the eventual giver of a new industry fabric.
Blockchain is a peer-to-peer trustless network that keeps records of digital assets without any central authority. With the passage of time, the sustainability issue of blockchain is rising. This paper discusses two major sustainability issues of blockchain: power consumption and scalability. It discusses the challenge of power consumption by analyzing various approaches to estimating power consumption in the literature. A case study of bitcoin is presented for this purpose. The study presents a review of the growing energy consumption of bitcoin along with a solution for immersion cooling in blockchain mining. The second challenge addressed in this research is scalability. With the increase in network size, scalability issues are also increasing as the number of transactions per second is decreasing. In other words, blockchain is observing low throughput with its increase in size. The paper discusses research studies and techniques proposed in the literature. The paper then investigates how to scale blockchain for better performance.
Khulud Salem Alshudukhi, Maher Khemakhem, Fathy Eassa, Kamal Jambi
In the Internet of Things (IoT), technological developments have increased the significance of federated cloud systems with integrated cloud providers for exchange transactions. Monolithic IoT systems implement service-oriented architecture (SOA), which is complex for supporting scalability and communicating transactions in a federated cloud system. One weakness of conventional security methods is that they depend on a centralized party, which means there is a single point of failure for the system. In contrast, blockchain (BC) and microservice (MS) technologies allow services to split for independent tasks. In this research paper, we introduce BC security managers based on MS technology for federated cloud systems in an IoT environment. In addition, we present the design of the Federation Security System Manager (FSSM) MS with interoperability features. This enables the exchange of transactions between permissioned BC managers at different cloud providers, with some constraints. Furthermore, a security framework based on MSs and BCs is implemented to ensure security and protect access control. The security functions are deployed based on a smart contract between the permissioned BC managers to achieve interoperability. Finally, we introduce the development process of the proposed framework, which allows for interoperability and ensures the security and privacy of the participating data for a distributed IoT based on the federated cloud system.
Blockchain mining pools assist in reducing computational load on individual miner nodes via distributing mining tasks. This distribution must be done in a non-redundant manner, so that each miner is able to calculate block hashes with optimum efficiency. To perform this task, a wide variety of mining optimization methods are proposed by researchers, and most of them distribute mining tasks via statistical request processing models. These models segregate mining requests into non-redundant sets, each of which will be processed by individual miners. But this division of requests follows a static procedure, and does not consider miner specific parameters for set creation, due to which overall efficiency of the underlying model is limited, which reduces its mining performance under real-time scenarios. To overcome this issue, an Incremental & Continuous Q-Learning Framework for generation of miner-specific task groups is proposed in this text. The model initially uses a Genetic Algorithm (GA) method to improve individual miner performance, and then applies Q-Learning to individual mining requests. The Reason for selecting GA model is that it assists in maintaining better speed-to-power (S2P) ratio by optimization of miner resources that are utilized during computations. While, the reason for selecting Q-Learning Model is that it is able to continuously identify miners performance, and create performance-based mining pools at a per-miner level. Due to application of Q-Learning, the model is able to assign capability specific mining tasks to individual miner nodes. Because of this capability-driven approach, the model is able to maximize efficiency of mining, while maintaining its QoS performance. The model was tested on different consensus methods including Practical Byzantine Fault Tolerance Algorithm (PBFT), Proof-of-Work (PoW), Proof-of-Stake (PoS), and Delegated PoS (DPoS), and its performance was evaluated in terms of mining delay, miner efficiency, number of redundant calculations per miner, and energy efficiency for mining nodes. It was observed that the proposed GA based Q-Learning Model was able to reduce mining delay by 4.9%, improve miners efficiency by 7.4%, reduce number of redundant computations by 3.5%, and reduce energy required for mining by 7.1% when compared with various state-of-the-art mining optimization techniques. Similar performance improvement was observed when the model was applied on different blockchain deployments, thus indicating better scalability and deployment capability for multiple application scenarios.
Since its inception as one of the Bitcoin's underpinning technologies, the concept of Blockchain has traversed a long way from being merely a secure distributed ledger meant only for storing cryptocurrencies-based financial transactions to implementing innovative and revolutionary distributed systems for multifarious purposes.One of the contemporary and out-of-the-box Blockchain-based projects, namely Hyperledger, promises to make preeminent use of this technology by promoting cross-industry collaboration in developing Blockchain-based solutions, thus, opening a new chapter in distributed computing.However, attributing to its underlying design, leveraging Hyperledger-Fabric (HF) features still lacks an analysis from the perspective of security risks and efficiency concerns pertaining to real-time distributed computing-based systems and applications.In this regard, we investigate the HF architecture, along with various research endeavours undergone by researchers in recent years to combat its security and performance-related challenges.In light of the identified limitations and bottlenecks, we present our conceptual proposal and feasible insights for improving the efficacy of HF-based systems while not compromising their security.
When there are loopholes in smart contracts or changes in demand, the existing three-tier model can only implement partial on-chain upgrades and the security of on-chain upgrades cannot be guaranteed. In this study, we optimized the three-tier smart contract model and proposed a four-tier smart contract model that includes the proxy, verification, business, and storage layers. The proxy layer is used to link contracts with other layers, the verification layer is used to check the integrity, boundary values, and abnormal processes of contracts, the business layer is used to execute business logic, and the storage layer is used to store data uniformly. On the basis of the proposed model, an on-chain upgrade and verification algorithm is proposed, which implements on-chain upgrade, on-chain verification, and version compatibility of contracts. We then design an information exchange system based on the proposed model and algorithm and test it based on the FISCO BCOS platform. Experiments show that, compared to the three-tier model, the proposed four-tier model and algorithm can implement the on-chain upgrade and reduce the contract complexity and data migration cost at the cost of some overall deployment.