Abstract:

The recent outbreak of COVID-19 has taken the world by surprise, forcing lockdowns andstraining public health care systems.

COVID-19 is known to be a highly infectious virus, and infectedindividuals do not initially exhibit symptoms, while some remain asymptomatic.

Thus, a non-negligiblefraction of the population can, at any given time, be a hidden source of transmissions. In response, manygovernments have shown great interest in smartphone contact tracing apps that help automate the difficulttask of tracing all recent contacts of newly identified infected individuals.

However, tracing apps have gener-ated much discussion around their key attributes, including system architecture, data management, privacy,security, proximity estimation, and attack vulnerability. In this article, we provide the first comprehensivereview of these much-discussed tracing app attributes. We also present an overview of many proposed tracingapp examples, some of which have been deployed countrywide, and discuss the concerns users have reportedregarding their usage.

We close by outlining potential research directions for next-generation app design,which would facilitate improved tracing and security performance, as well as wide adoption by the populationat large.