SNARKs to the rescue: proof-of-contact in zero knowledge

Abstract

This paper describes techniques to help with COVID-19 automated contact tracing, and with the restoration efforts. We describe a decentralized protocol for ``proof-of-contact'' in zero knowledge where a person can publish a short cryptographic proof attesting to the fact that they have been infected and that they have come in contact with a set of people without revealing any information about any of the people involved. More importantly, we describe how to compose these proofs to support broader functionality such as proofs of $n$th-order exposure which can further speed up automated contact tracing. The cryptographic proofs are publicly verifiable, and places the burden on the person proving contact and not on third parties or healthcare providers rendering the system more decentralized, and accordingly more scalable.

10 pages, early draft

References in corpus (4)

• PACT: Privacy Sensitive Protocols and Mechanisms for Mobile Contact Tracing
• Epione: Lightweight Contact Tracing with Strong Privacy
• Assessing Disease Exposure Risk with Location Data: A Proposal for Cryptographic Preservation of Privacy
• Anonymous Collocation Discovery: Harnessing Privacy to Tame the Coronavirus