A new phone-tracing technology could tell if you've been exposed to the coronavirus — without sacrificing privacy. 130 researchers are offering it to countries for free.

· The novel coronavirus excels at spreading because it's contagious when there are few or no symptoms.
· That's why governments are resorting to lockdowns, travel bans, and other economy-crippling restrictions.
· A team of 130 volunteer researchers just rolled out a technology framework that aims to help people return to...