Towards Large-Scale and Privacy-Preserving Contact Tracing in COVID-19 Pandemic: A Blockchain Perspective

Area of Science:

• Computer Science
• Cybersecurity
• Network Engineering

Background:

• The COVID-19 pandemic increased demand for activity-tracking and location-based services, particularly for automated contact tracing.
• Key challenges include ensuring data security, protecting location privacy, and efficiently deploying Internet of Things (IoT) devices for monitoring.

Purpose of the Study:

• To propose a decentralized and permissionless blockchain protocol, Bychain, to address data security, privacy, and deployment challenges in activity-tracking systems.
• To develop a privacy-preserving short-range communication (SRC) protocol and an incentive mechanism for IoT witness deployment.

Main Methods:

• Developed a privacy-preserving SRC protocol using interactive zero-knowledge proofs and key escrow to decouple identity from location data.
• Designed an artificial potential field-based incentive allocation mechanism to encourage optimal IoT witness deployment for maximum coverage.
• Implemented and evaluated the Bychain protocol using Bluetooth 5.0, analyzing performance metrics like storage, CPU, power, and time delay.

Main Results:

• The Bychain protocol successfully decouples personal identity from on-chain location information while allowing ownership claims without private key disclosure.
• The incentive mechanism effectively encourages IoT witnesses towards maximizing monitoring coverage.
• Real-world evaluation demonstrated the protocol's performance in terms of storage, CPU utilization, power consumption, and time delay.

Conclusions:

• Bychain offers a robust solution for secure and private activity tracking using blockchain technology.
• The proposed methods enhance IoT device deployment efficiency and monitoring capabilities, crucial for applications like contact tracing.
• The study provides a comprehensive real-world performance evaluation, validating the protocol's effectiveness and security.