This open access book describes Smittestopp, the first Norwegian system
for digital contact tracing of Covid-19 infections, which was developed
in March and early April 2020. The system was deployed after five weeks
of development and was active for a little more than two months, when a
drop in infection levels in Norway and privacy concerns led to shutting
it down. The intention of this book is twofold. First, it reports on the
design choices made in the development phase. Second, as one of the only
systems in the world that collected population data into a central
database and which was used for an entire population, we can share
experience on how the design choices impacted the system's operation. By
sharing lessons learned and the challenges faced during the development
and deployment of the technology, we hope that this book can be a
valuable guide for experts from different domains, such as big data
collection and analysis, application development, and deployment in a
national population, as well as digital tracing.