[$] Open-source contact tracing, part 1

One of the responses to the COVID-19 pandemic consists of identifyingcontacts of infected people so they can be informed about the risk; that will allow themto search for medical care, if needed. This is laborious work if it is donemanually, so a number of applications have been developed to help withcontact tracing. But they are causing debates about their effectiveness andprivacy impacts. Many of the applications were released under open-sourcelicenses. Here, we look at theprinciples of these applications and the software frameworks used to build them;part two will look into some applications in more detail,along with the controversies (especially related to privacy) around these tools.