Undetected Infected despite the corona app on your phone
The Dutch government wants the Dutch to be able to be warned by an app that they may be infected. How would that work?
Even if everyone in the Netherlands has an app on their smartphone that checks whether there has been contact with a carrier of the Covid-19 virus, people can become infected without being noticed.
That is the sobering message from Prof. Bram Nauta, designer of chips for wireless communication and professor at the University of Twente. Nevertheless, Nauta is in favour of the contact app that Minister Hugo de Jonge (Health, CDA) announced Tuesday evening in the fight against the pandemic. “It is better than nothing.”
The idea behind the app is that someone who tests positive for Covid-19 reports this in the application. The phone then sends a message to all smartphones that have been in the vicinity for the past few weeks: “You have been in contact with an infected person”. Minister De Jonge specifically mentioned Bluetooth as a technique with which such an app can record who someone has been around. According to experts, that is the only technology on smartphones that is suitable for this.
But Bluetooth is by no means a blessing. “If we’re outside and you have your smartphone in your left pocket, and I’m right against you with my phone in my right pocket, chances are those apps won’t see each other,” says Nauta. “Our bodies prevent that. And outside there is no reflection of the signal through walls.”
In a train, for example, this is the case, so that a corona app may think that someone else is nearby, when in reality it is a few banks away. Prof. Nauta therefore expects many ‘false positives’ when the app will soon be installed en masse on smartphones.
Testing, tracking and staying at home
Despite the risk of many unnecessary concerns, Prof. Nauta considers the use of the technology desirable. “I would like to know that I have been around a virus carrier. Then I can be tested and possibly quarantined. ”
With this he points to an important condition for the success of the contact app that the cabinet is considering: large-scale testing. If the lockdown measures in the Netherlands are alleviated, it is essential to detect new infections as soon as possible. “Testing, tracing and staying at home will become the mantra of the Ministry of Health in the new phase of corona control” Minister De Jonge wrote to the House of Representatives.
The test capacity of the Dutch laboratories will be expanded considerably in the coming weeks; now only vulnerable groups, patients with symptoms and vital health workers are tested for the virus.
It is still unclear who will make the app and what it will look like exactly. Coronia envoy Feike Sijbesma said this week that the government may work with an Asian supplier. One of the apps developed in the Netherlands is called PrivateTracer. The protocol is as privacy-friendly as possible, says initiator Salim Hadri. “We will make the source code fully public, so that experts from, among others, the Dutch Data Protection Authority can check how it works and help others. This is the only way that there will be sufficient confidence in our approach and enough people will install the app.”
De Jonge emphasized on Tuesday that it is “of the utmost importance” that privacy is guaranteed. If less than 60 percent of the population installs the application, the tracking system will not be effective, recent British research found. Whether the Ministry of Health prefers an ‘open source solution’, a spokesperson could not say on Wednesday.
Privacy advocates are critical of the Cabinet’s app plans. “This can lead to countless wrongful suspicions, stigmatization, unnecessary unrest and panic,” said a statement from the Privacy First Foundation. “Even anonymised, the data from such apps can still be traced back to individuals via linking. With large-scale use, this leads to a surveillance company in which everyone is observed and registered and people feel constantly monitored.”
Several European initiatives say that they only collect data that is necessary for the contact investigation and also store it only on the user’s smartphone. This should reduce the risk of abuse, including by governments. For example, the ‘ DP3T initiative ‘, led by Spanish scientist Carmela Troncoso, does not record any personal or location data. A register of devices that have been in the vicinity of the smartphone is created via Bluetooth technology. DP3T seems to be aware of the shortcomings of Bluetooth that University of Twente professor Nauta has identified: by also counting the frequency and duration of the connections with a virus carrier’s phone, an estimate is made of the risk of infection.
Bluetooth connections can also be hacked. “A hacker can lie that he has corona or lie that he does not have it,” said Professor Nauta. He says there is something to come up with: an approval code that a doctor must put in the app.
Large-scale sabotage is also possible. “Someone can build a very strong Bluetooth transmitter, so that everyone around that transmitter is declared infected in a large radius. But then you have to be a bit more convenient.” And the question is why a handy hacker would want to do something like this.
The contact app is not the only technological tool that should help the Netherlands after relieving the ‘intelligent lockdown’. Minister De Jonge also presented a home reporting app on Tuesday, which can be used in combination with the others. After a warning from the contact investigation via one app, exposed persons are asked to report their health status to a doctor in the region on a daily basis via the self-reporting app. De Jonge hopes that the monitoring of patients by the GGDs will become less labor-intensive and that more virus carriers will be identified.
Translated from the article “Ongemerkt besmet ondanks de corona-app op je telefoon”Published by NRC authors Wilmer Heck & Rik Wassens on April 9th 2020