COVID-19 Antibody Test Certification: There's an app for that

As the Coronavirus Pandemic of 2019/2020 unfolds, a COVID-19 'Immunity Passport' has been mooted as a way to enable individuals, especially those in healthcare and other key industries, to return safely back to work at 'the right moment'. Despite a number of ethical, social, legal, and biological dilemmas (e.g. 'COVID-19 antibody testing' is itself unproven), verifiable test results could well become highly desirable, at least in certain key sectors. But a 'paper certificate' has a number of dilemmas of its own, including weak tamper-proofness and rather arcane and clumsy verifiability. To address many of the underlying issues involved in certification, and as a proof of concept for future pandemics, we have developed a prototype mobile phone app that facilitates instant verification of tamper-proof test results. Personally identifiable information is only stored at the user's discretion, and the app allows the end-user selectively to present only the specific test result with no other personal information revealed. Behind the scenes it relies upon (a) the 2019 World Wide Web Consortium standard called 'Verifiable Credentials', (b) Tim Berners-Lee's decentralised personal data platform 'Solid', and (c) a consortium Ethereum-based blockchain. These enable the aforementioned mixture of verifiability and privacy in a manner derived from public/private key pairs and digital signatures, generalised to avoid restrictive ownership of sensitive digital keys and/or data. We describe the underlying principles, ethical considerations, and a 9-step use case scenario.