Smart Contract-Based Access Control for the Internet of Things (1802.04410v1)

Abstract: This paper investigates a critical access control issue in the Internet of Things (IoT). In particular, we propose a smart contract-based framework, which consists of multiple access control contracts (ACCs), one judge contract (JC) and one register contract (RC), to achieve distributed and trustworthy access control for IoT systems. Each ACC provides one access control method for a subject-object pair, and implements both static access right validation based on predefined policies and dynamic access right validation by checking the behavior of the subject. The JC implements a misbehavior-judging method to facilitate the dynamic validation of the ACCs by receiving misbehavior reports from the ACCs, judging the misbehavior and returning the corresponding penalty. The RC registers the information of the access control and misbehavior-judging methods as well as their smart contracts, and also provides functions (e.g., register, update and delete) to manage these methods. To demonstrate the application of the framework, we provide a case study in an IoT system with one desktop computer, one laptop and two Raspberry Pi single-board computers, where the ACCs, JC and RC are implemented based on the Ethereum smart contract platform to achieve the access control.

• The paper proposes a novel framework that decentralizes IoT access control using Ethereum smart contracts to combine static and dynamic validation.
• The methodology leverages Access Control, Judge, and Register Contracts to efficiently manage access policies and handle misbehavior reports.
• The framework demonstrated enhanced security, scalability, and adaptive misbehavior management in a practical IoT deployment case study.

Smart Contract-Based Access Control for the Internet of Things

The Internet of Things (IoT) presents a complex environment where enhanced security measures, such as access control, become essential. The paper, "Smart Contract-Based Access Control for the Internet of Things," proposes a novel framework that leverages blockchain technology, specifically smart contracts, to address the distributed and trustworthy access control issues within IoT systems. This approach integrates multiple smart contracts for efficient access and misbehavior management, crucial for the robust functioning of diverse IoT applications.

Framework Overview

The framework comprises three primary types of smart contracts: Access Control Contracts (ACCs), a Judge Contract (JC), and a Register Contract (RC).

• Access Control Contracts (ACCs) are designed to implement access control methods for specific subject-object pairs. They combine static access validation, based on predefined policies, with dynamic validation that considers the subject's behavior. This dual mechanism offers granularity in restricting access and enforcing security.
• The Judge Contract (JC) supports dynamic validation by evaluating misbehavior reports from ACCs. By maintaining a record of subject misbehaviors, the JC determines appropriate penalties, enhancing the system's resilience against malicious activities.
• The Register Contract (RC) serves as a repository for managing access control methods. It registers, updates, and deletes access control and misbehavior judging methods, facilitating efficient and organized contract management.

Methodology

The proposed framework pioneers in decentralizing the traditional access control mechanisms predominant in IoT systems. By utilizing Ethereum's blockchain capabilities, it addresses the single point of failure issue that characterizes centralized systems. Moreover, the improvements in transparency, integrity, and security inherent to blockchain technology are adeptly harnessed within the proposed framework.

A detailed case paper showcases the implementation of this framework on a small IoT network, consisting of common computing devices (desktop, laptop) and Raspberry Pi units. The choice of Ethereum as the foundational blockchain technology enables the smart contracts to be both decentralized and immutable, providing credible validation processes and efficient management of IoT interactions.

Results and Implications

The implementation of this framework presents several promising results:

• Security and Trustworthiness: By relying on blockchain's transparency and immutability, the framework achieved secure and trustworthy access control in IoT settings, as validated through the case paper.
• Scalability: Given that smart contracts are executed across the Ethereum network, the proposed framework offers scalability. Though not explicitly discussed in the paper, the ability to adapt to larger IoT deployments with minimal performance degradation is implied.
• Dynamic Misbehavior Management: The inclusion of dynamic validation mechanisms that adapt based on subject behavior significantly enhances preventive security measures. The paper demonstrates that this can effectively deter or mitigate unauthorized accesses and ensure compliance with predefined policies.

Future Developments

The implementation raises several avenues for further exploration:

• Optimizing Ethereum’s Gas Costs: Given the computational expenses associated with executing smart contracts on blockchain networks, future research can investigate optimizing gas costs for more economical access control implementations.
• Privacy Considerations: As data privacy becomes increasingly significant, integrating privacy-preserving techniques within this framework could prove beneficial, ensuring that subject-object interactions remain confidential while still secure.
• Integration with AI Tools: Leveraging machine learning models to predict potential security threats based on historical data could further enhance the framework's ability to preempt unauthorized access attempts.

While the paper effectively addresses several crucial concerns, ongoing advancements in both IoT devices and blockchain technology suggest the need for continuous improvement and adaptation of such frameworks. As a significant stride towards practical, secure IoT deployment, this work highlights the dynamic convergence of IoT requirements with blockchain's robust capabilities, setting a precedence for future research and commercial applications within this domain.