Blockchain Technologies for the Internet of Things: Research Issues and Challenges (1806.09099v1)

Abstract: This paper presents a comprehensive survey of the existing blockchain protocols for the Internet of Things (IoT) networks. We start by describing the blockchains and summarizing the existing surveys that deal with blockchain technologies. Then, we provide an overview of the application domains of blockchain technologies in IoT, e.g, Internet of Vehicles, Internet of Energy, Internet of Cloud, Fog computing, etc. Moreover, we provide a classification of threat models, which are considered by blockchain protocols in IoT networks, into five main categories, namely, identity-based attacks, manipulation-based attacks, cryptanalytic attacks, reputation-based attacks, and service-based attacks. In addition, we provide a taxonomy and a side-by-side comparison of the state-of-the-art methods towards secure and privacy-preserving blockchain technologies with respect to the blockchain model, specific security goals, performance, limitations, computation complexity, and communication overhead. Based on the current survey, we highlight open research challenges and discuss possible future research directions in the blockchain technologies for IoT.

Blockchain Technologies for IoT: Research Issues and Challenges

Introduction

The convergence of blockchain technologies with the Internet of Things (IoT) poses significant opportunities and challenges. This paper provides a detailed survey of existing blockchain protocols applicable to IoT networks, an area growing exponentially across various sectors, including intelligent transportation and smart cities. The integration of blockchain frameworks potentially aids in addressing IoT's inherent QoS limitations, primarily caused by constrained computational, storage, and bandwidth resources.

Application Domains

Blockchain's distributed ledger technology offers promising applications in multiple IoT domains:

• Internet of Vehicles (IoV): Proposals include decentralized security models leveraging elliptic curve cryptography to ensure secure communication without central authority intervention.
• Healthcare: Blockchain-based systems provide solutions for the immutability and privacy of electronic health records (EHRs).
• Energy Sector: Smart Grids can utilize blockchain to ensure data transparency and security against false data injections via consensus mechanisms.
• Cloud and Fog Computing: Blockchain helps manage resources and security in decentralizing IoT network management.

Threat Models in IoT Blockchain

The paper categorizes threat models affecting IoT blockchain infrastructure into five main classes:

1. Identity-Based Attacks: Including Sybil and key attacks, these exploit identity spoofing to gain unauthorized access.
2. Manipulation-Based Attacks: Such as modification and replay attacks, often target transaction integrity.
3. Cryptanalytic Attacks: Notably, quantum attacks target the blockchain's cryptographic underpinnings.
4. Reputation-Based Attacks: Hiding blocks and whitewashing attacks seek to falsely manipulate participant reputations.
5. Service-Based Attacks: DDoS and double-spending attacks threaten service availability and financial integrity.

Comparative Analysis

The paper provides a taxonomy of existing blockchain-based methods, comparing their effectiveness against these threats and their computational efficiencies. Various strategies, such as digital signatures, attribute-based cryptography, and consensus mechanisms, are explored for enhancing security and privacy in blockchain-IoT integrations.

Open Challenges and Future Directions

Several noteworthy challenges remain:

• Energy Efficiency: With blockchain's resource-intensive nature, especially with consensus protocols like PoW, energy-efficient methods are crucial for IoT's constrained environments.
• Dynamic Security Frameworks: There is a need for adaptable security solutions that cater to IoT's diverse devices and environments.
• Compliance with Regulations: Blockchain systems face inherent conflicts with regulations such as GDPR, especially concerning data erasure and privacy.
• Trust and Social Integration: Incorporating blockchain into social networks and trust mechanisms could mitigate issues like misinformation spread.

Conclusion

While substantial progress has been made, the intersection of blockchain and IoT necessitates further research in ensuring secure, efficient, and sustainable applications. The outlined challenges and potential paths forward emphasize the need for continued innovation in this dynamic field, paving the way for more resilient IoT solutions.