## 4 Case Study
### Privacy Policies  
For the purposes of this case study, the necessary privacy policy documents have been prepared in a simple XML schema, based on the attributes and elements introduced in [8] (removed for review). This schema consists of simple elements along with some attributes, in an attempt to describe a strict privacy policy in a structured yet easy way. Documents presented at this section contain information only for the personal identifiers and data required for the successful completion of AVT electronic service. Each document consists of a root _Privacy_Policy_ element, a _Policy_ID_ element, which includes a unique policy document identifier, based on which the referencing from lower levels is achieved, along to a _Data_ element. The latter is divided into two sub-elements, _Personal_Identifiers_ and _Personal_Data_, based on data type. The Hellenic Government Privacy Policy, presented at Table 1 below, states that _National Taxation Identifier (line A.7)_, _License Plate_ information _(line A.14)_, and _First and Last name (line A.19)_ must be processed as confidential data and can be stored by service providers. There is no reference to how long SPs are allowed to store this data and therefore this is subject to be specified by lower level policy documents. However abstract this policy may seem, these are the fundamental obligations that are imposed and must be endorsed by all underlying ministerial departments and SPs. Table 2 below presents the privacy policy of the Ministry of Finance. For all data types contained within the document there is a clear reference to a policy document with _P_Ref_ID = \"001\" (lines B.7, B.13, and B.17)_ with regards to the Hellenic Government Privacy Policy. Statements regarding data processing remain the same and three new specifications are introduced; At line _B.8_ it is stated that National Taxation Identifier can processed for Identification purposes, at lines _B.9_ and _B.15_ the corresponding data can be retained for 365 days and at _B.19_ first and last names can be retained for 90 days. The lack of \(<\)_Transmitted\(>\)_ elements means that what imposed by referenced document is still in effect. Figure 3: Case Study Privacy Policies Hierarchy. \begin{table}
\begin{tabular}{c c} \hline \hline
**Line** & **Privacy Policy Content** \\ \hline A.1 & \textless{Privacy\_Policy}\textgreater{} \\ A.2 & \textless{Policy\_ID=\"001\"\textgreater{}} \\ A.3 & \textless{Description\_}\textgreater{} \\ A.4 & \textless{Policy\_ID\textgreater{}} \\ A.5 & \textless{Data\textgreater{}} \\ A.6 & \textless{Personal\_Identifiers\textgreater{}} \\ A.7 & \textless{Identifier\_ID=\"26\"\textgreater{}} National Taxation Identifier (AFM) \\ A.8 & \textless{Processed=\"Confidential\"\textgreater{}\textless{}/Processed\textgreater{}} \\ A.9 & \textless{Storage=\"Yes\"\textgreater{}\textless{}/Storage\textgreater{}} \\ A.10 & \textless{Transmitted=\"Yes\"\textless{}/Transmitted\textgreater{}} \\ A.11 & \textless{Identifier\_ID\textgreater{}} \\ A.12 & \textless{Personal\_Identifiers\textgreater{}} \\ A.13 & \textless{Personal\_Data\textgreater{}} \\ A.14 & \textless{Data\_ID=\"873\"\textgreater{} License Plate} \\ A.15 & \textless{Processed=\"Confidential\"\textgreater{}\textless{}/Processed\textgreater{}} \\ A.16 & \textless{Storage=\"Yes\"\textgreater{}\textless{}/Storage\textgreater{}} \\ A.17 & \textless{Transmitted=\"Yes\"\textless{}/Transmitted\textgreater{}} \\ A.18 & \textless{/Data\_ID\textgreater{}} \\ A.19 & \textless{Data\_ID=\"32\"\textgreater{} First and Last Name} \\ A.20 & \textless{Processed=\"Confidential\"\textgreater{}\textless{}/Processed\textgreater{}} \\ A.21 & \textless{Storage=\"Yes\"\textgreater{}\textless{}/Storage\textgreater{}} \\ A.22 & \textless{Transmitted=\"Yes\"\textless{}/Transmitted\textgreater{}} \\ A.23 & \textless{/Data\_ID\textgreater{}} \\ A.24 & \textless{/Personal\_Data\textgreater{}} \\ A.25 & \textless{/Data\textgreater{}} \\ A.26 & \textless{/Privacy\_Policy} \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Hellenic Government Privacy Policy.