PriLok: Citizen-protecting distributed epidemic tracing

Abstract

Contact tracing is an important instrument for national health services to fight epidemics. As part of the COVID-19 situation, many proposals have been made for scaling up contact tracing capacities with the help of smartphone applications, an important but highly critical endeavour due to the privacy risks involved in such solutions. Extending our previously expressed concern, we clearly articulate in this article, the functional and non-functional requirements that any solution has to meet, when striving to serve, not mere collections of individuals, but the whole of a nation, as required in face of such potentially dangerous epidemics. We present a critical information infrastructure, PriLok, a fully-open preliminary architecture proposal and design draft for privacy-preserving digital contact tracing, which we believe can be constructed in a way to fulfil the former requirements. Our architecture leverages the existing regulated mobile communication infrastructure and builds upon the concept of "checks and balances", requiring a majority of independent players to agree to effect any operation on it, thus preventing abuse of the highly sensitive information that must be collected and processed for efficient contact tracing. This is technically enforced with a largely decentralised layout and highly resilient state-of-the-art technology, which we explain in the paper, finishing by giving a security, dependability and resilience analysis, showing how it meets the defined requirements, even while the infrastructure is under attack.

TB-ICT: A Trustworthy Blockchain-Enabled System for Indoor COVID-19 Contact Tracing

“…Some certified nodes collect the information about the close interactions and submit them to the blockchain, and smart contracts will be used for the proof of location without violation of users' privacy. PriLok is proposed in [46], which is a permissioned blockchain that should be handled by collaboration of various entities, e.g., health and public authorities and telecommunication firms. PriLok uses a cellular network with the idea that the BLE technology and smartphones are not available as they should be specifically for older people.…”