# Contact Tracing: Ensuring Privacy and Security
## 4 Framework Analysis and Design  
In this section, we will introduce the framework we built and tested against several leading European implementations. Based on the comprehensive literature survey, the draft framework that preserves privacy and protects the security of users is demonstrated in Table 2. The table provides information on and an overview of requirements that have to be met to make an app that is both private and secure within the European Union. Notice that a decentralised design is required, in line with the EU and research. This (draft) framework in itself satisfies objective five, but it is unknown whether the current, leading implementations meet this framework and these requirements.  
To validate the draft framework, the project tested several leading European implementations against it. The results gathered from this paper can verify whether the GAEN-enabled implementations comply with the framework and are, as such, ensuring privacy and security. The requirements presented later, translate to the questions in Table 3  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Identifier,** & **Requirement Number,** & **Objective** \\ \hline \(1.1\) & Users cannot be tracked & 1 (Threat) \\ \hline \multirow{4}{*}{\(1.2\)} & Users cannot be re-identified either after & \\  & infection or otherwise. This includes & \\  & when uploading infectious temporarily & \\  & 1 (Threat) & \\ \hline \multirow{4}{*}{\(1.3\)} & Users cannot be pressured into disclosing & \\  & sensitive data & \\ \hline \multirow{4}{*}{\(1.4\)} & Replay attacks leading to false alerts & \\  & are impossible & \\ \hline \multirow{4}{*}{\(1.5\)} & Users cannot be identified through & \\  & profiling or application use & \\ \hline \multirow{4}{*}{\(2.1\)} & Proximity tracing is exclusively & \\  & performed with BLE & \\ \hline \multirow{4}{*}{\(2.2\)} & Decentralised design conforming with & \\  & DP-3T/GAEN & \\ \hline \multirow{4}{*}{\(2.3\)} & The BLE beacons are pseudonymous and & \\  & rotates frequently. This includes fake & \\  & hardware addresses. & \\ \hline \multirow{4}{*}{\(3.1\)} & Every implementation is approved by the & \\  & privacy authority with a valid & \\  & PIA published. & \\ \hline \multirow{4}{*}{\(3.2\)} & The contract tracing system is voluntary & \\  & and dismantled after the pandemic & \\  & preventing mission creep. & \\ \hline \multirow{4}{*}{\(3.3\)} & Google and Apple dismantle the & \\  & GAEL-API after the pandemic & \\ \hline \multirow{4}{*}{\(3.4\)} & The backend stores data exclusively in & \\  & the EU with no data transfers outside & \\  & the EU. & \\ \hline \multirow{4}{*}{\(4.1\)} & The app follows a security standard to & \\  & ensure continuous security evaluation & \\ \hline \multirow{4}{*}{\(4.2\)} & The app source code is open and secured & \\  & against malicious updates & \\ \hline \multirow{4}{*}{\(4.3\)} & Google and Apple disclose the & \\  & GAEN API & \\ \hline \hline \end{tabular}
\end{table}
Table 2: Draft framework for privacy and security.  
that direct further research. Note that requirement 2.2 is not tested and considered one of the future works. This requirement stipulates a decentralised design, which is an integral part of the experiments shown later. The research focuses only on decentralised designs. It is worth noting that Table 3 identifies three different research methods to investigate the answers to the questions.