Contact tracing is a concept in process that has emerged in the context of COVID-19, specifically with the development of deconfinement measures focused on avoiding a new wave of infections.
Several countries have introduced technological systems based on the tracking of contacts. In general terms, these systems evolve around applications that inform their users on a possible contagion state after being in contact with people who have tested positive with Coronavirus. The objective of this technological uprising centers its focus on preventing future contagions by creating a network of contacts.
Although some applications developed in a few countries such as China have been more intrusive in the privacy of their citizens, (they are not anonymous, they collect personal data and locate by GPS), other places have chosen a friendly system with all the concepts mentioned above. Mainly, by using bluetooth technology it allows studying mobility without affecting privacy: while signals are being emitted from a mobile phone, nobody else knows which phone is communicating. Also, to reinforce this privacy, they have developed applications that use decentralized systems.
Decentralized applications to ensure data protection
There are two models of contact tracking applications: centralized and decentralized. The difference between them is the way and the place where the exchanged data is stored. In the decentralized system the information is stored only on the owner’s mobile phone. However, in centralized systems, the data ends up in a central server controlled by an entity.
A protocol to develop tracking applications called DP-3T has been launched in several countries. It is based on the decentralized model, so that no one stores user data. The system arises from an investigation carried out at the Polytechnic School of Lausanne, in Switzerland and predates the proposal developed by Google y Apple, which is also based on the decentralized model.
How do “Contact Tracing” apps function?
The contact tracing applications work through Bluetooth, which allow detecting other devices connected to this technology when they are within a determined radius. The applications allow to issue different random open codes (or identifiers) constantly, and record the codes that are transmitted by other nearby applications. In this way, a network of contacts is created. In the case that a person becomes infected, (s)he publishes his codes to a server. Individuals who have been in contact with the infected can check their code list.
Through the application, users can download the public list of positives and check if they have had contact with any of them, in this way users can be notified by their own device, that will be the one to check all the information in isolation. Thus, once users are notified, they can take preventive measures and collaborate against the spread of the coronavirus. All this, always safeguarding the anonymity of the identity’s users.
The following illustration has outlined the process very well: