# Contact Tracing: Ensuring Privacy and Security
## 2 Digital Contact Tracing: What Is Missing? The idea of using technology in epidemiology is not unique to the 2020 pandemic. The use of algorithms, data, and computational power to revolutionise epidemiology has been argued previously [6]. However, it was not until the publication of the work in [7] that digital contact tracing received significant attention. The authors modelled the growth of COVID-19 to assess the effectiveness of digital contact tracing. They found that the problem of pre-asymptomatic and asymptomatic cases alone is enough to sustain the exponential \begin{table}
\begin{tabular}{c c c} \hline \hline
**Objectives** & **Methodology** & **Method** \\ \hline Threats Investigation & Qualitative & Literature Analysis \\ \hline Investigating Available Techniques & Qualitative & Literature Analysis \\ \hline Privacy definition for contact tracing apps & Qualitative & Literature Analysis \\ \hline Security definition for contact tracing apps & Qualitative & Literature Analysis \\ \hline Framework Design & Prototyping & Implementation \\ \hline Framework Review & Quantitative & Experimentation \\ \hline Framework validation & Prototyping & Implementation \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The used research methodologies. growth of COVID-19. If the delay between finding new cases and notification of contacts is three days or less, epidemic control is possible. Moreover, immediate notification by an application could lead to epidemic control if user adoption is 56% or higher. Lower user adoption can still contribute significantly to halting the exponential spread of the epidemic, when combined with additional interventions, such as face masks, frequent hand sanitation, and social distancing. \"Digital contact tracing could play a critical role in avoiding or leaving lockdown\" [7]. It is worth noting that two countries, amongst many, that successfully employed digital contact tracing solutions are China and South Korea. However, whether their methods respect privacy and security are debatable. For example, China ties its social gigantic application WeChat ([[https://www.wechat.com](https://www.wechat.com)]([https://www.wechat.com](https://www.wechat.com)) accessed on 22 September 2021) to various other governmental IT systems. Realising this threat, privacy and security advocates worldwide quickly warned of the dangers of digital contact tracing. As early as April 2020, an impressive global community of scientists released a press statement calling for digital solutions that respect privacy and security [8]. Even with the debate on privacy and security still raging, governments decided to develop contact tracing applications. Most, but not all, based their apps on the Google and Apple exposure notification (GAEN) framework. This framework is, in essence, an extra layer between the operating systems of both Google (i.e., Android) and Apple (i.e., iOS) and a third-party contact tracing application. GAEN uses Bluetooth low energy (BLE) hardware for proximity tracing. GAEN is essentially based on the decentralised DP-3T protocol and promises a privacy-preserving method to allow digital contact tracing. However, some governments remain unconvinced. The French government specifically decided to use its proprietary implementation, not wanting to rely on Apple and Google. It is argued that GAEN is inherently dangerous especially against a malicious authority [9] and is considered too restricted to perform digital contact tracing effectively. It proposes to use more, instead of less, personal information [10]. Although governments are rushing to develop contact tracing applications, often based on Google and Apple exposure notification (GAEN), the fundamental questions of privacy and security are debated and remain unanswered to this day. Although the argument continues, the question remains: what system ensures privacy and security best?