This is like the Keymaster and the Gatekeeper getting together in “Ghostbusters.” Something awe-inspiring is about to happen annnnnd probably not in a good way.

But it’s good news under the circumstances, he said to himself, a sinking feeling in his stomach.

Our current predicament is difficult but straightforward:

1. We need to get the economy going at the earliest conceivable moment it’s safe to do so.

2. There are two prerequisites to doing that, according to every infectious disease specialist in creation. First, we need to make testing widely available so that we can catch new cases early, before they turn into new outbreaks. Second, we need a system of contact tracing so that those who’ve been in recent proximity to a person who’s just tested positive can immediately be notified to self-isolate. If we can manage both, the public can go back to work and only those at special risk need to be removed from the labor force for a few weeks at a time.

3. Contact tracing traditionally requires lots of manpower to interview people, catalog their interactions, and reach out to those with whom they’ve been in contact. We don’t have that manpower.

4. Contact tracing also requires good administration. We don’t have good administration. We have the opposite. Some of our nurses wear garbage bags to protect themselves from infection because we can’t get them anything better, for cripes sake. If we leave it to the federal government to build an effective contact tracing system, this country will look like “The Stand” by Election Day.

Fortunately, in an age in which we all carry a device that tracks our movements, contact tracing can now be done remotely with scarcely any manpower required. And because those devices are built by competent private entities, not the federal garbage-bag government, this form of contact tracing is likely to work. If we can build out testing soonish to support the new system, we could be in a position to reopen the economy sooner than we think. It’s good news.

The only catch is that it means granting two of the world’s tech behemoths minute-by-minute updates on our movements *and* our health status. And, in so doing, triggering a cultural shift in which we’ll all be less reluctant to provide information like that to authorities forever after.

Anyway, big, big news:

A number of leading public health authorities, universities, and NGOs around the world have been doing important work to develop opt-in contact tracing technology. To further this cause, Apple and Google will be launching a comprehensive solution that includes application programming interfaces (APIs) and operating system-level technology to assist in enabling contact tracing. Given the urgent need, the plan is to implement this solution in two steps while maintaining strong protections around user privacy.

First, in May, both companies will release APIs that enable interoperability between Android and iOS devices using apps from public health authorities. These official apps will be available for users to download via their respective app stores.

Second, in the coming months, Apple and Google will work to enable a broader Bluetooth-based contact tracing platform by building this functionality into the underlying platforms. This is a more robust solution than an API and would allow more individuals to participate, if they choose to opt in, as well as enable interaction with a broader ecosystem of apps and government health authorities. Privacy, transparency, and consent are of utmost importance in this effort, and we look forward to building this functionality in consultation with interested stakeholders. We will openly publish information about our work for others to analyze.

If I understand that correctly, they’re going to roll this out quickly by first providing it as an app available for download — called Contact Tracing, neatly enough. Then, in stage two, they’re going to build it right into the iOS and Android operating systems while providing some sort of option to opt out. That’ll deliver the software to three billion people or so. An obvious early question: How thorough will the “opt out” be, exactly? Given how much personal information is collected surreptitiously by tech companies already, it’s impossible to believe that the movements of opt-outs won’t be quietly tracked too. The “opt out” might prevent you from being alerted if someone you’ve been in contact with is sick, but no one wants to opt out of that part. It’s the movement tracking to which some will object. Is that realistically preventable once it’s built into the OS? Is there any doubt that eventually the default setting on contact tracing will be to turn it on and force users to turn it off?

To assure the public that their privacy will be protected, Apple and Google say they’ll build encryption into the movement data. What might that look like in practice? A few days ago the Atlantic described how Germany is handling the problem:

Buermeyer told me that one possibility is to program phones to broadcast a different ID every 30 minutes. So, for example, if I went to Starbucks in the morning, my phone would broadcast one ID over Bluetooth to all the other phones in the café. An hour later, at lunch with a friend, it would broadcast a different ID to all the other phones at the restaurant. Throughout the day, my phone would also receive and save IDs and log them in an encrypted Rolodex.

Days later, if I were diagnosed with the coronavirus, my doctor would ask me to upload my app’s data to a central server. That server would go through my encrypted Rolodex and find all of the temporary IDs I had collected. An algorithm would match the temporary IDs to something called a push token—a unique code that connects each phone to the app. It could then send each phone an automated message through the app: PLEASE BE ADVISED: We have determined that in the past few days, you may have interacted with somebody … At no point in this entire process would anybody’s identity be known to either the government or the tech companies operating the central server.

The Apple/Google app also won’t disclose identities or locations in informing people that they’ve been in contact with someone who’s sick. All you’ll know is that you may have been exposed and it’s time to hunker down for a few weeks. In fact, enlarge the images in this tweet and you’ll see that the Apple/Google system will function very similarly to the German one:

Apple/Google partner on automatic, anonymised bluetooth-based contact tracing. Very clever. pic.twitter.com/3aruVkov8x

— Benedict Evans (@benedictevans) April 10, 2020

I think most people will opt in. Why not, if it means we exit this national nightmare sooner rather than later? Even if some opt out for privacy reasons, there are likely to be enough opting in that partial surveillance will allow us to cut down on outbreaks dramatically anyway. The head of NIH wrote about the potential for smart phones to help beat pandemics just yesterday and noted that “researchers estimate that about 60 percent of new COVID-19 cases in a community would need to be detected — and roughly the same percentage of contacts traced — to squelch the spread of the deadly virus.” Can we get to 60 percent opt-ins? Easily, I suspect, given the tremendous costs of a sustained epidemic.

Why, by next year we may be so comfortable with the system that they’ll expand it to track flu transmissions too. Better public hygiene through total information awareness! Imagine how much good an Apple/Google herpes tracker app might do. Coming in 2025, probably.

Two points in closing. One: American businesses will need to prepare for a *lot* more sick leave for employees, including employees who end up not actually being sick. If you get an alert that you’ve been in touch with someone who’s tested positive, you’re supposed to self-quarantine for a period. You might not be infected, of course; it’s a precaution in case you are. Potentially people could be forced off the job repeatedly over the course of a year because they had the bad luck of repeatedly running into people who came down with COVID-19 in the preceding days. There’ll be a strong economic incentive for all workers to eliminate all unnecessary contacts with other people until a vaccine is available, purely for the sake of being able to work steadily. But then, given that social distancing is our only defense against infection, that incentive exists already.

Two: None of this works without widely available testing. Trump may not grasp that but everyone else should. The whole point of contact tracing is to identify sick people quickly and then reach out to those with whom they’ve been in contact to isolate them before the virus spreads further. If we’re not testing abundantly, that system breaks down on the very first step. It makes me wonder what happens if we can’t build out testing quickly enough. Will the app allow people to “self-report” possible cases of COVID-19? For example, might there be an option available to notify your recent contacts if you’re currently suffering from fever, dry cough, and chills even though you haven’t been able to get tested? That would be an even bigger nightmare for employers since it could create a cascade of absences without a single confirmed case of coronavirus. And some sociopaths out there would doubtless abuse the system by claiming to have symptoms when they really don’t just to mess with people. But if the guiding principle in contact tracing is “better safe than sorry,” well, better safe than sorry.