Blockchain-based vaccination certificates management

With the explosion of COVID-19 cases and the government’s needs to control virus spreading, the development of effective and robust systems for managing vaccination certificates to restrict citizens’ activities has been in the centre of many governments. This paper proposes a system that allows for the update of the status of certificates and bases its function on a specific form of logs stored on Blockchains and a set of rules for the interpretation of these logs. Also an outline of a proof of concept implementation of the system in Ethereum together with a cost and security analysis are provided in the paper. The proposed architecture provides several benefits with the most prominent one being the suspension of certificates in case an already vaccinated individual is found positive. In existing certificate management systems a vaccinated individual that is tested positive still holds a valid vaccination certificate during the self-isolation period. This vulnerability allows infected individuals to commute freely and thus facilitates the spread of the pandemic. The proposed solution is not limited to COVID-19 related certificates, but rather it could be deployed in any kind of digital certificate.