As states begin easing pandemic restrictions, Americans are hearing that a robust regime of “testing and tracing” is critical to reopening safely. Traditional contact tracing relies on meticulous interviews with patients to identify potential exposures, but today, many see a role for cutting edge technology in the fight against COVID-19. Many such proposals raise privacy and civil liberties concerns: Does high-tech contact tracing require giving government access to a database of Americans’ locations? Can the process be done anonymously? Could an architecture of monitoring designed to mitigate a pandemic be coopted for less salutary purposes? Technologists and privacy experts will explore an array of different models for digitally assisted tracing and exposure notification—and how to fight contagion without sacrificing privacy.