Building Trust with a Contact Tracing Application: A Blockchain Approach

On March 11, 2020, the novel coronavirus (COVID-19) was declared a global pandemic. With no treatment or vaccine available at the time, it was necessary to rely on non-pharmaceutical methods for case identification and contact tracing. This kind of approach has good results in detecting and preventing tuberculosis, sexually transmitted infections, and vaccine-preventable diseases. Contact tracing and keeping safe distances are crucial to containing the spread of COVID-19. Nonetheless, contact tracing is a complex intervention, it involves quarantining and investigating close contacts. Manual contact tracing methods are slow, require a large amount of effort, and more often than not rely on the memory or assumptions of individuals. To combat these downsides, contact tracing applications were developed, resulting in quicker and more reliable recognition of infected individuals. However, because of the complex nature of these applications and their lack of transparency, a large portion of the population started doubting the privacy of the data collected. Soon after, many of these applications started to dwindle in the user department, which caused a feedback loop. "If fewer people are using the application, the application itself becomes useless, and there is no longer a reason to use it." Is clear that the main issue behind their downfall was an overwhelming lack of trust. In response, this paper will analyze how the use of blockchain technology can help the development of a more transparent application. And describe how a proof of work based on this concept was implemented. On the same note, it will also approach why was Hyperledger Sawtooth chosen, instead of more popular solutions such as Bitcoin or Ethereum.