Towards Privacy-preserving Digital Contact Tracing

摘要

There have been several digital contact tracing apps proposed and deployed. However, these have not been widely adopted owing to apprehensions surrounding privacy and security. We propose a blockchain-based privacy-preserving contact tracing protocol, "Did I Meet You" (DIMY), that provides full-lifecycle data privacy protection on the devices themselves as well as on the back end, to address most of the privacy concerns associated with existing protocols. We have employed Bloom filters to provide efficient privacy-preserving storage and have used the Diffie-Hellman key exchange for secret sharing among the participants. DIMY’s footprint on the storage space of clients’ devices and blockchain-based back end is significantly lower than other similar state-of-the-art apps. We have implemented DIMY with the front-end application on an Android platform and have used Hyperledger Fabric for the back end.