The Koronavilkku app was completed at breakneck speed

– This may become one of the most downloaded apps in Finland.

This is how technology specialist Sami Köykkä from Solita describes his work.

Solita, a Finnish company focusing on technology, strategy and design, won the bidding competition for the development of a coronavirus tracking app organised by THL, the Finnish Institute for Health and Welfare, and the development work began straight away around Midsummer in June. A dozen or so other European countries are also developing their own national mobile apps and twenty more are meaning to do so.

– An equivalent app is already in use in a few European countries, such as Italy, Germany, Ireland and Switzerland, Köykkä says.

In Finland, the trial use of the Koronavilkku app began on the 4th of August. The app officially launched on the 31st of August.

Mobile phones sniffing each other

The idea behind a coronavirus tracking app sounds simple. Phones with the app installed send a signal to each other when the users of the phones are in close proximity. If the users remain in contact long enough so that they could transfer the virus, the phone records a tracking code.

An app user who is diagnosed with coronavirus receives a confirmation code from health care that they can enter into the app to warn people they come into contact with about the contagion – the authorities do not do this on behalf of the user.

An app user who receives this warning and could therefore have been exposed to the virus receives clear instructions to contact health care to discuss further course of action.

The operating systems of the most common phones have been equipped with the Exposure Notifications interface that collects anonymous data about distances to other phones.

– This interface alone is not enough to track the coronavirus. It requires the support of a national app that we can all download to help prevent the spread of infections in Finland. Each country can only have one app that is authorised by the authorities, and in Finland this app is managed by THL, says Köykkä.

At first, the app was installed onto the phones of Solita employees and they would walk around the office in order to find out how the phones observe each other.

Safety first

Jaakko Hannikainen is a member of Solita's coronavirus app development team. Even though he is a Master of Arts who majored in computer science, he has joined the ranks of Academic Engineers and Architects in Finland TEK that are full of Masters of Science in Technology.

– There have been times when I've felt like a bit of a weirdo in that bunch, Hannikainen says with a laugh.

Hannikainen has been enjoying his time at Solita for three and a half years now. When developing the coronavirus app, his task became the realisation of the integration that aims at the secure launch of the app.

– My job is to ensure that no one can modify the app during the period between when it leaves our hands and when it arrives at the app stores. We also make sure that the app is safe from possible attacks by hackers. So my work could be thought of as a kind of data security analysis, in a broad sense.

Hannikainen emphasises that only ready-made solutions that have already been found to be secure are used in the development of the tracking app.

– The work took place in the middle of the holiday season, which added to the scheduling challenges. However, the schedule remained realistic. I didn't have to put in any overtime, even though many members of the team have stretched their hours.
The app's core development team contains ten or so employees, but the project involved dozens of Solita employees in one capacity or the other.

– In March almost all of us withdrew to remote work, but we began to gradually return to the office at the end of the summer. We conducted an in-house survey on the popularity of remote work and the responses were split almost evenly between remote work and office work. Personally, I would prefer working at the office, but because of the coronavirus situation I have mostly been working from home.

Hannikainen describes the development of the app as an interesting and downright inspiring project.

– You feel like you are doing something truly useful here, even though my previous projects have also been useful.

Anonymity is guaranteed

Solita's technology specialist Sami Köykkä emphasises that the coronavirus tracking app does not breach people's anonymity.

– The app doesn't collect personal or movement data. But if you have downloaded the app, the anonymous tracking codes of phones you come across will be collected in your phone's memory.

This encounter data will not be sent outside of the phone and the data will also be automatically deleted from the phone's memory after a period of three weeks, or when the danger of contagion has passed.

According to Köykkä, some countries such as China have also developed a more precise system for tracking users that is based on GPS location. Such a system was also planned in Norway but the idea was scrapped due to pushback from citizens.

– All of the data collected by the Finnish app is anonymous and no additional data is stored. The app was published as open source so that everyone could see for themselves that this really is the case. The app and the operators involved in the project were audited by National Cyber Security Centre Finland to ensure that both data and privacy are protected. Even the Communicable Diseases Act starts from the position that the user cannot be tracked.

While Solita was developing the app itself, separate interfaces were also created for use by authorities and they were given user training.

– The authorities have expressed their wish that as many Finns as possible should install the free-of-charge coronavirus tracking app hitting app stores at the end of August onto their phones. This way each of us can help warn others in case we fall ill and, of course, also receive warnings from others. The app also allows us to reduce the chance that we might be spreading the virus unknowingly as asymptomatic carriers, Köykkä says to summarise.