22 April 2020
(University of Helsinki & Finnish Centre for AI)
Many European countries are planning to deploy contact tracing apps to help COVID-19 epidemic management. Privacy is an absolute requirement for such apps, and typically they would only share a list of anonymous identifiers of recent contacts when someone is diagnosed positive. We propose additional opt-in sharing of numbers of daily contacts of users under strict privacy guarantees from differential privacy. Such data would help epidemic modelling and monitoring the impact of non-pharmaceutical interventions needed for managing the epidemic.