https://www.vox.com/recode/2020/4/10/21216675/apple-google-covid-coronavirus-contact-tracing-app

The new contact-tracing tool, explained.

Just when you were wondering why the world’s biggest tech companies weren’t doing more to fight the coronavirus pandemic, Apple and Google made a big announcement: They are joining forces to build an opt-in contact-tracing tool using Bluetooth technology that could help public health officials track the spread of Covid-19, the disease caused by the novel coronavirus. The new tool brings with it not only hope for a quicker end to the pandemic, but also a host of privacy and security concerns.