CoviChain: A Blockchain Based COVID-19 Vaccination Passport
This addresses the problem of balancing public health needs with privacy rights for citizens and governments, though it appears incremental as it builds on existing blockchain and biometric techniques.
The paper tackles the privacy concerns of COVID-19 vaccination passports by proposing a blockchain-based framework that uses two-factor authentication and iris extraction with locality sensitive hashing to create unique identifiers for locating vaccination records without storing personal information, aiming to enable safe societal reopening while protecting citizen anonymity.
Vaccination passports are being issued by governments around the world in order to open up their travel and hospitality sectors. Civil liberty campaigners on the other hand argue that such mandatory instruments encroach upon our fundamental right to anonymity, freedom of movement, and are a backdoor to issuing "identity documents" to citizens by their governments. In this paper we present a privacy-preserving framework that uses two-factor authentication to create a unique identifier that can be used to locate a person's vaccination record on a blockchain, but does not store any personal information about them. Our main contribution is the employment of a locality sensitive hashing algorithm over an iris extraction technique, that can be used to authenticate users and anonymously locate vaccination records on the blockchain, without leaking any personally identifiable information to the blockchain. Our proposed system allows for the safe reopening of society, while maintaining the privacy of citizens.