PaperlayerView exact revision on arXiv

Source-linked AI summary

Integration of Blockchain and Cloud of Things: Architecture, Applications and Challenges

Dinh C Nguyen, Pubudu N Pathirana, Ming Ding, Aruna Seneviratne

arXiv:1908.09058v2cs.CR

TL;DR

Cloud of Things faces centralization and resource constraints, while blockchain introduces computational and security limitations that complicate integration. The paper surveys BCoT architectures, applications, platforms, services, and research challenges, concluding that the integration offers security, privacy, and service-support benefits while retaining important scalability and resource-efficiency issues.

  • Problem

    Cloud of Things relies on centralized models and constrained IoT devices, while blockchain introduces computational, energy, throughput, and security limitations for integration.

  • Method

    The paper presents an extensive survey of BCoT background, integration motivations, architecture, applications, platforms, services, and research challenges.

  • Results

    The review finds that BCoT supports secure data sharing, traceability, access control, decentralized cloud services, and more secure cooperation across application domains.

  • Takeaways & Limitations

    BCoT is presented as a promising integration for cloud IoT applications, but its deployment requires attention to energy efficiency, scalability, standardization, and security.

  • Takeaways & Limitations

    Blockchain consensus can require extensive processing power and energy, making blockchain infeasible for resource-constrained IoT devices in some Cloud of Things applications.

Abstract

from arXiv · show

The blockchain technology is taking the world by storm. Blockchain with its decentralized, transparent and secure nature has emerged as a disruptive technology for the next generation of numerous industrial applications. One of them is Cloud of Things enabled by the combination of cloud computing and Internet of Things. In this context, blockchain provides innovative solutions to address challenges in Cloud of Things in terms of decentralization, data privacy and network security, while Cloud of Things offer elasticity and scalability functionalities to improve the efficiency of blockchain operations. Therefore, a novel paradigm of blockchain and Cloud of Things integration, called BCoT, has been widely regarded as a promising enabler for a wide range of application scenarios. In this paper, we present a state-of-the-art review on the BCoT integration to provide general readers with an overview of the BCoT in various aspects, including background knowledge, motivation, and integrated architecture. Particularly, we also provide an in-depth survey of BCoT applications in different use-case domains such as smart healthcare, smart city, smart transportation and smart industry. Then, we review the recent BCoT developments with the emerging blockchain and cloud platforms, services, and research projects. Finally, some important research challenges and future directions are highlighted to spur further research in this promising area.

I. INTRODUCTION

BCoT integrates blockchain with Cloud of Things to combine decentralized security and privacy mechanisms with cloud-enabled scalability and elasticity. This survey reviews the integration's architecture, applications, platforms, and open challenges.

  • Background: Blockchain provides a decentralized, immutable, and publicly accessible ledger secured through consensus mechanisms and cryptography.Its peer-to-peer architecture removes dependence on a single controlling entity and supports trustworthy transaction validation.
  • Background: Cloud of Things combines IoT devices with cloud computing to process and manage services despite constrained device resources.The paradigm supports flexible and robust service delivery, but conventional infrastructures rely heavily on centralized communication models.
  • Integration Motivation: The integration is motivated by replacing centralized Cloud of Things models with more decentralized ecosystems enabled by blockchain.The paper presents BCoT as a complementary integration rather than a standalone blockchain or cloud deployment.
  • Integration Motivation: BCoT combines blockchain's decentralization with Cloud of Things elasticity and scalability to address centralized architectures, privacy, and network-security challenges.Blockchain can support decentralization, access control, data ownership, and cooperation, while cloud resources can accelerate blockchain transaction processing and improve fault tolerance.
  • Survey Scope: Earlier surveys examined blockchain, IoT, cloud, or related application domains, but lacked a comprehensive review of their combined integration.The paper addresses this gap by covering background, integrated architectures, application domains, platforms, services, and research challenges.
  • Survey Scope: The survey reviews BCoT architectures, application domains, emerging platforms and services, and future research challenges.Its stated contributions include coverage of BCoT models across applications and lessons from their adoption.

B. Structure of The Survey

The survey introduces blockchain and Cloud of Things, presents their integration architecture, and reviews motivations, platforms, applications, challenges, and future directions. It emphasizes blockchain’s decentralized operation, security properties, and continuing scalability and energy constraints.

  • The survey covers blockchain and CoT background, integration motivations, architecture, developments, application domains, platforms, services, challenges, and future directions.
  • 1) Blockchain:: Blockchain uses decentralized peer-to-peer operation, distributed ledgers, consensus, and smart contracts to validate and protect linked transaction blocks.Blocks are connected through hash labels, making prior data traceable and resistant to modification.
  • 1) Blockchain:: Blockchain’s decentralization removes reliance on central control and supports tamper resistance, shared verification, and reduced single-point-failure risks.Users can access, verify, and track transaction activities with equal rights across the network.
  • 1) Blockchain:: Blockchain integration with CoT must address energy efficiency, resource constraints, throughput, block-generation time, and rapidly expanding blockchain size.
  • 1) Blockchain:: Bitcoin processes up to 4 transactions/second, Ethereum about 20 transactions/second, and Visa up to 1667 transactions/second.

2) Cloud of Things:

CoT combines IoT connectivity with cloud storage, processing, and automatic resource provisioning, but centralized architectures create availability, privacy, and integrity concerns. Blockchain offers complementary security and privacy support, while its own computational, cost, and security limitations constrain deployment.

  • 2) Cloud of Things:: IoT connects heterogeneous devices for automatic sensing, processing, and communication, while CoT adds cloud-based storage, analytics, remote execution, and resource provisioning.
  • 2) Cloud of Things:: CoT integration is motivated by cloud security challenges, blockchain’s technical limitations, and opportunities from combining both technologies.
  • 2) Cloud of Things:: Centralized cloud IoT architectures risk service unavailability when central services fail, face privacy concerns over data use, and expose outsourced data to unauthorized modification or deletion.
  • 2) Technical Limitations of Blockchain:: Blockchain deployment in CoT remains constrained by consensus complexity, high operational costs, and security flaws including potential 51% attacks.
  • 2) Cloud of Things:: Blockchain can support CoT decentralization, data security, and privacy, while CoT can provide cloud resources for intensive blockchain computation and data storage.

3) The Opportunities of Integration of Blockchain and CoT:

Integrating blockchain with Cloud of Things creates BCoT opportunities centered on decentralized management, privacy, security, and simpler deployment. The surveyed literature also extends these ideas through cloud services, applications, and multicloud collaboration.

  • Opportunities of Integration: BCoT enables decentralized management through peer-to-peer control, replicated ledgers, and distributed consensus among cloud nodes and IoT devices.This structure is described as eliminating single-point failure bottlenecks, preventing service disruption, and enhancing data availability.
  • Opportunities of Integration: Blockchain properties such as immutability, integrity, and transparency can enhance privacy for IoT data outsourced to clouds and exchanged among users.The paper describes blockchain consensus as making practical data-modification attacks nearly impossible.
  • Opportunities of Integration: BCoT improves system security through cryptographic confidentiality, replicated availability, cloud-supported off-chain storage, and cloud security tools for blockchain software.Records are hashed and transactions are signed, while cloud resources can support availability during network interruptions.
  • Opportunities of Integration: Blockchain-as-a-Service reduces implementation complexity by providing managed platforms and cloud infrastructure for running blockchain algorithms.The integration is presented as supporting large-scale BCoT deployment with simple and inexpensive implementations.
  • Opportunities of Integration: Cloud providers including Amazon, Microsoft, IBM, and Oracle have launched BaaS platforms for IoT, including an Amazon-based healthcare example.These platforms are presented as evidence of industry activity around blockchain–cloud integration.
  • Opportunities of Integration: The survey reviews existing BCoT models and extends the discussion to security applications, identity management, cloud offloading, and multicloud collaboration.Multicloud integration is motivated for complex IoT systems requiring substantial resources and serving numerous users.

B. The Conceptual BCoT Architecture

The conceptual BCoT architecture connects IoT devices, cloud-hosted blockchain services, and applications through three layers. Cloud resources provide blockchain management, storage, computation, and scalable data services for IoT systems.

  • Architecture: The conceptual architecture contains three layers: IoT, cloud blockchain, and application.The model is designed to represent both multiple-cloud and single-cloud BCoT settings.
  • IoT Layer: IoT devices collect local data, transmit it through gateways, and use blockchain accounts to perform transactions and interact with cloud services.Resource-limited devices may participate as lightweight blockchain nodes.
  • Architecture: The architecture positions BCoT as middleware that combines secure blockchain network management with on-demand, reliable computing for large-scale IoT applications.Cloud resources can also support consensus participation, including mining tasks performed through virtual cloud machines.
  • Cloud Blockchain Layer: The cloud blockchain layer hosts BaaS to provide secure network management and services such as shared ledgers, consensus, smart contracts, and cryptography.Shared ledgers record exchanges, consensus verifies transactions, and smart contracts support access authentication and data-sharing verification.
  • Cloud Blockchain Layer: BaaS also provides cloud blockchain storage that manages IoT data through hash values and periodic verification to detect modification.IPFS is cited as an example of blockchain-based storage available on cloud infrastructure.
  • Cloud Computing Services: Cloud computing services support IoT applications through SaaS, IaaS, and PaaS, while processing and storing aggregated data on-chain or off-chain.Cloud servers can apply data mining or machine learning to offloaded IoT data, and multiple clouds can support sharing or collaboration.

3) Application Layer:

The application layer spans healthcare and other industrial domains, with the surveyed healthcare literature emphasizing secure sharing, protected storage, access control, traceability, and efficient medical services. It also identifies a storage trade-off: keeping all health data on-chain can slow transactions and increase privacy concerns.

  • Application Layer: BCoT applications cover smart healthcare, smart transportation, smart city, smart energy, and smart industry, providing network management, QoS improvement, security, and privacy.The review focuses on application findings and lessons across these scenarios.
  • Health Data Sharing: Cloud IoT healthcare systems support online processing and storage of electronic health records, while mobile users access medical information for monitoring.The literature associates these capabilities with on-demand healthcare services, cost savings, and improved experience.
  • Health Data Sharing: Healthcare data-sharing schemes store encrypted records or medical data in cloud storage while keeping indexes or hash metadata on blockchain under smart-contract management.This design prevents arbitrary modification and supports traceability, access control, and data integrity.
  • Health Data Sharing: Storing all health data on blockchain can slow transaction operations and expose sensitive patient information to data-leakage and sharing-security concerns.A proposed alternative encrypts large datasets off-chain in cloud storage and keeps only metadata such as hash values on blockchain.
  • Lessons Learned: BCoT healthcare systems use blockchain, cloud storage, and smart contracts for secure access verification, transaction tracking, and protection against cloud-data modification.The reviewed lessons emphasize secure sharing and improved security for cloud healthcare storage.
  • Healthcare Services: BCoT can support healthcare services including health monitoring, patient diagnosis, and healthcare remedy evaluation with high security and efficiency.These services are presented as potential improvements enabled by the integration.

2) Smart City:

In smart cities, BCoT combines cloud computing for large-scale IoT data processing with blockchain for distributed security, integrity, and control. The reviewed applications include city operations, smart homes, auditing, lightweight blockchain, and decentralized data management.

  • Smart City: Smart cities combine ubiquitous IoT devices, heterogeneous networks, large-scale storage, and cloud processing to provide services for citizens.This infrastructure creates the setting in which BCoT security and processing capabilities are applied.
  • Security Services: Blockchain can provide integrity, authenticity, confidentiality, and non-repudiation through decentralized security architectures for smart cities.These cryptographic properties respond to privacy, integrity, and trust bottlenecks in data-based services.
  • Security Services: Smart-city research includes blockchain-based auditing of cloud data integrity and authorization or delegation architectures for cloud IoT systems.One framework uses a data auditing blockchain to handle auditing requests between data owners and cloud service providers.
  • Security Services: A proposed smart-city architecture uses smart block, peer-to-peer network, and cloud layers with lightweight blockchain to reduce computation and resource demands.Communications among IoT devices, cloud storage, and peer-to-peer nodes are recorded as transactions.
  • Security Services: BCoT offers smart-city security services by pairing cloud capacity for large data streams with blockchain-based distributed and secure control of operations.The review presents this integration as addressing smart-city architectural challenges.
  • Smart Home Services: BCoT supports smart-home monitoring, management, access control, flexible storage, and secure transaction processing among devices, owners, and external users.The reviewed smart-home architectures use cloud storage and blockchain-based overlays or networks to support confidentiality, integrity, and availability.

3) Smart Transportation:

BCoT applies blockchain and cloud computing to secure and decentralize smart transportation, especially vehicular communication and services. Reviewed systems address privacy, trust, resource limitations, and service coordination across connected vehicles.

  • Smart transportation faces security risks from dynamic V2V communication and reliance on centralized authorities.
  • BCoT combines cloud data management with blockchain security to support secure vehicular communication and services.
  • Vehicular Communication Management: Cloud and blockchain architectures address VANET storage, computation, and bandwidth limitations through interconnected vehicular, roadside, and central clouds.
  • Vehicular Communication Management: Blockchain enables peer-to-peer vehicle networks for service management, value exchange, and collaborative trust.
  • Secure Vehicular Services: Applications include task scheduling, data carpooling, insurance management, software updates, vehicular reporting, and trust control.

4) Smart Industry:

BCoT extends blockchain and cloud computing across smart manufacturing, supply chains, and energy systems. The reviewed applications target decentralized coordination, improved security, efficient operations, and lower management effort.

  • BCoT organizes smart-industry applications into smart manufacturing, smart energy, and smart supply chains.
  • Smart Manufacturing: Centralized manufacturing architectures have limitations in flexibility, efficiency, and security, motivating distributed BCoT designs.
  • Smart Manufacturing: BCmfg uses a five-layer distributed peer-to-peer architecture to support cloud manufacturing and trusted data sharing.
  • Smart Supply Chain: BCoT supports faster and more secure cooperation in supply-chain and logistics activities through decentralized and immutable blockchain properties.
  • Smart Energy: Blockchain consensus optimizes and secures energy-management operations through decentralized verification among energy users.
  • Lessons Learned: BCoT can improve manufacturing efficiency, reduce operational costs, minimize management effort, and strengthen supply-chain privacy and security.
  • Lessons Learned: Cloud computing provides storage and management services while supporting blockchain-based decentralized energy operations.

5) Other BCoT Applications:

Beyond transportation and industry, BCoT is applied to cloud services, resource management, and education. These applications use blockchain’s integrity, transparency, access control, and trusted-ledger properties alongside cloud capabilities.

  • BCoT applications include smart cloud services, smart resource management, and smart education.
  • Smart Cloud Services: Blockchain-based cloud services address payment fairness, data deletion verification, BIM provenance, and decentralized storage.
  • Smart Resource Management: BCoT resource-management systems support real-time processing, resource-intensive applications, mining, consensus, and monitored cloud usage.
  • Smart Education: Educational applications use immutable blockchain ledgers and cloud computing to validate and securely share certificates, student information, and institutional learning data.
  • Lessons Learned: The reviewed applications associate BCoT with better cloud-service efficiency and security, transparent resource management, robust access control, and trusted educational collaboration.

B. BCoT Platforms and Services

BCoT platforms and services combine decentralized blockchain storage with cloud infrastructure and Blockchain-as-a-Service. The reviewed ecosystem supports distributed IoT data storage, deployable blockchain services, and secure industrial data sharing.

  • Cloud Blockchain Platforms: Traditional centralized cloud storage limits user control and raises security, privacy, cost, and scalability concerns for IoT data.
  • Cloud Blockchain Platforms: Decentralized cloud-blockchain storage distributes IoT data across peer-to-peer storage nodes instead of relying on a central provider.
  • BaaS Services for CoT: Blockchain-as-a-Service integrates blockchain with cloud computing to provide infrastructure and technical support for developing, verifying, and deploying BCoT applications.
  • BaaS Services for CoT: Commercial BaaS providers can accelerate BCoT deployment by reducing the need for infrastructure installation and system investment.
  • Research Projects: A blockchain-based vehicle-data platform enables drivers, manufacturers, and service providers to share vehicle data securely in untrusted vehicular networks.

V. RESEARCH CHALLENGES AND DISCUSSION

The survey identifies major BCoT challenges spanning standardization, security, privacy, intelligence, and resource management. It emphasizes unresolved vulnerabilities in heterogeneous systems and outsourced IoT data environments.

  • The survey highlights standardization, security vulnerability, privacy leakage, intelligence, and resource management as five major BCoT challenges.
  • Standardization: BCoT lacks common standards, with heterogeneous protocols and provider-specific designs complicating interoperability across blockchain and CoT systems.
  • Security vulnerability: Security risks persist across CoT and blockchain, including identity, access control, integrity, and 51% attacks that can halt transaction confirmations.
  • Privacy leakage: Off-chain cloud storage and blockchain transactions can expose IoT data through unauthorized processing, external access, modification, or transaction leakage.

4) Intelligence:

BCoT research has concentrated on storage, sharing, and security, while intelligent services and adaptive resource management remain important development needs. The survey discusses cloud-based analytics, machine learning, and standardization-related measures as possible responses.

  • Intelligence: BCoT applications mainly provide data storage, sharing, and security, while intelligent analytics, decision systems, and automatic management receive less research attention.
  • Resource Management: Resource management in cloud blockchain requires adaptive designs for allocation, bandwidth reservation, task allocation, and workload allocation under changing service demands.
  • Standardization: Standardization may require agreements among providers covering network settings, blockchain deployment, device integration, and payment schemes.
  • Intelligence: Machine learning can support intelligent BCoT services, including healthcare assessment and cloud-based smart-city data collection, processing, and visualization.
  • Resource Management: Machine learning embedded in smart contracts has been proposed to optimize datacenter energy use according to user requests and potentially reduce scheduling and migration costs.

A. Improving Blockchain Performance for Future BCoT

Future BCoT systems must improve blockchain efficiency while handling growing IoT data and demanding network environments. The survey points to machine learning, big data, 5G, and selective blockchain participation as relevant directions.

  • Blockchain efficiency is constrained by transaction verification, authentication, mining resource demands, limited scalability, and growing storage requirements.
  • Future BCoT must address growing IoT traffic and dynamic data management to support ubiquitous services, higher performance, and improved security in 5G and beyond.
  • Machine learning is identified as an efficient approach for supporting networking optimization, system management, and service management in future BCoT.
  • Big data can support storage, data cleaning, and analytics for rapidly growing blockchain-IoT data, while BCoT can improve data integrity and privacy preservation.
  • Blockchain can support 5G services through trust management, attack detection, secure key management, and transparent resource or device-to-device data exchange.
Loading 1908.09058v2…