Apple and Google announced Friday an unprecedented collaboration to leverage smartphone technology to help trace and contain the spread of coronavirus. The collaboration will open up their mobile operating systems to allow for the creation of advanced “contact-tracing” apps, which will run on iPhones and Android phones alike. The apps would work by using the Bluetooth technology in mobile phones to keep track of every other phone a person comes into close contact with over the course of a day; if that person later finds out they have Covid-19, they can use the same system to alert all those people, dating back to before they would have become infectious. The idea is to help national governments roll out these contact-tracing apps to allow lockdowns to be lifted earlier, by letting authorities much more readily identify new clusters of infection. The technology would also help those who have been exposed to a person with Covid-19 self-isolate before they themselves become infectious. Concerns are already being raised about the effectiveness of such technology and privacy concerns surrounding its implementation. The companies are opting to use Bluetooth to track who has been in contact with Covid-19 cases rather than location services to protect some user privacy, but advocacy groups are still wary. “No contact-tracing app can be fully effective until there is widespread, free, and quick testing and equitable access to healthcare,” Jennifer Granick, the surveillance and cybersecurity counsel at the ACLU said. “People will only trust these systems if they protect privacy, remain voluntary, and store data on an individual’s device, not a centralized repository.” Similar apps have already been trialled in nations including Singapore and China. In Europe, the Czech Republic says it will release such an app this month. Britain, Germany and Italy are also developing their own tracing tools. But the apps have been held back by a combination of reduced uptake – the Singaporean app is used by 12% of the city, limiting its effectiveness – and difficulties in working around privacy protections built into the iOS and Android operating systems. It is those limits that Apple and Google will be lifting, the companies announced today. Privacy and civil liberties activists have warned that such apps need to be designed so governments cannot abuse them to track their citizens. Apple and Google said in a joint announcement that user privacy and security are baked into the design of their plan. Pam Dixon, executive director of the World Privacy Forum, said she’ll be looking closely at the companies’ privacy assurances and for evidence that any health data they collect will be deleted once the emergency is over. “People are dying. We have to save lives. Everyone understands that,” she said. “But at some point, we’re going to have to understand the privacy consequences of this.” Security experts also note that technology alone cannot effectively track down and identify people who may have been infected by Covid-19 carriers. Such efforts will require other tools and teams of public health care workers to track people in the physical world, they say. In South Korea and China, such efforts have included the use of credit card and public transit records. Given the great need for effective contact tracing, the companies will roll out their changes in two phases. In the first, they will release software in May that lets public health authorities release apps for both Android and iOS phones. In the coming months, they will also build this functionality directly into the underlying operating systems. On Friday, the companies released preliminary technical specifications for the effort, which they called Privacy-Preserving Contact Tracing .