Mona is engaged with a work email on her smartphone as she enters a grocery store, while a man standing next to her waits to be served by the store cashier. As she continues with her task, she does not notice that he is within a one-meter range, and doesn’t see him coughing into his elbow. Hours later, a free app from the local Ministry of Health alerts her that she might have been exposed to someone with Covid-19. She receives this message because both she and the newly diagnosed Covid-19 sufferer had installed the app and had their Bluetooth settings turned on. All others who had downloaded the app and come into close proximity to the sufferer were also notified.
What is contact tracing?
Since Covid-19 first appeared, governments and tech companies have been planning to implement systems that use smartphone data to track how people interact in real life. The aim of these so-called contract tracing apps is to highlight contact between infected and susceptible people, even when it is unknown who is infected. Such apps can inform potentially exposed users without handing over location data to governments – in other words, they do not involve mass surveillance or invasion of privacy.
What this means is that these apps are able to keep an infected individual’s test results and personal data private while still warning anyone who might have entered their physical space. This is an important factor for giving large numbers of people the confidence to download the app, because high uptake will be a determining factor in the success of this technology.
Contact tracing apps are likely to play an increasingly important role in enabling governments to ease their Covid-19 restrictions. While it is important to stress that this technology can only ever be one part of the solution, if implemented correctly as part of a broader plan of measures, we believe contact tracing can be an invaluable tool for governments and healthcare authorities.
While other technologies such as GPS data are well known for tracking location data, Bluetooth has significant advantages in terms of precision for contact tracing.
Mobile apps using Bluetooth can constantly ping signals to nearby phones within a one-meter accuracy. In addition, Bluetooth technology is already extremely popular and enabled in the majority of smartphones, as it is the primary way we connect our smartphones to wireless headphones, speakers, smart watches, TVs, and more.
How is privacy maintained?
The best way of protecting the geolocation data that is usually used to track individuals is for governments and corporations not to collect it in the first place – this is how the app works.
Explaining this is slightly complicated, but here goes…
If two people come in close proximity for around 15 minutes, the app considers them to have had a “Contact Event”. Both phones then generate a locally unique, anonymized random number for that event, record the number, and transmit it to each other.
If a user later believes he or she is infected with Covid-19, they can ask the healthcare provider for a unique confirmation code that verifies their Covid-19 case is positive. This permission code is used so that malicious users cannot send false alarms and flood the system. When that confirmation code is entered, the app will automatically upload all the contact event numbers from that phone to a server (for a defined limited duration).
The server will then send out such contact event numbers to every phone in the system, where the app will verify if any of the codes received match their own log of contact events from the last two weeks. If any of the numbers match, the app will alert the user that they have been in contact with an infected person. Instructions then are sent to this user with videos about how to get tested or self-quarantined.
The app does not show the identity of any users as it only makes use of a random number that the two phones, which are in contact, are able to track later. Other phones or governments cannot capture such information, because it is stored locally on the users’ phones.
Who is making use of such technology?
Many countries have already implemented or started working on systems for containing Covid-19 by utilizing such technologies. Below are some of the authorities and countries looking at Contact Tracing technology:
- Singapore is using a Bluetooth based Contact Tracing app, called TraceTogether (https://www.tracetogether.gov.sg/)
- PEPP-PT teams in Europe is focusing on building an anonymous, easy-to-implement, internationally scalable, and essentially free smartphone-based approach (https://www.pepp-pt.org/)
- The UK has confirmed plans for its own Bluetooth based contact tracing app (https://www.bbc.com/news/technology-52263244?ocid=wsnews.chat-apps.in-app-msg.whatsapp.trial.link1_.auin)
- UAE have released TraceCovid which utilizes the same contact tracing technology (https://tracecovid.ae/)