# SMARTEN--A Sample-Based Approach towards Privacy-Friendly Data Refinement
## 5 Evaluation
### Feature Assessment  
As outlined in Section 2, data protection regulations such as the GDPR impose legal requirements on the data refinement process. In this feature assessment, we therefore investigate whether SMARTEN complies with these requirements.  
SMARTEN provides technical measures that ensure compliance with the _principles relating to processing of personal data_ (Art. 5). Data minimization is considered in many ways. First, data standards receive only insight into a small section of the data due to our sample-based approach. Second, by applying the privacy scripts in the Privacy Zone, the information content is minimized prior to processing. Third, even with respect to the non-disclosure requirements, the data processor receives only as much information as necessary, due to our two-stage signature approach. This fine-grained and target-oriented data minimization also ensures that the data processor is able to maximize the accuracy of the refined data. Furthermore, the provision of different variants of the refined data at different privacy levels enables to enforce a purpose limitation towards the data consumer.  
Since the non-disclosure requirements of the data producers are inseparably attached to the data by means of digital signatures, the _lawfulness of processing_ (Art. 6) as well as _conditions for consent_ (Art. 7)--including all their amendments in the subsequent articles (Art. 8 and Art. 9)--can be guaranteed by the data processor. Given the fact that a semi-honest-but-curious data processor can be assumed, it is sufficient to have two supervisory bodies in place, the privacy officer and the privacy engineer. Due to the measures introduced by SMARTEN, they are able to assess and ensure compliance with the requirements.  
SMARTEN adheres to the _transparency and information rights_ (Art. 12-Art. 14), as third-party auditors can monitor at any time on behalf of the data producer which data are present in which processing stage at the data processor. Furthermore, the non-disclosure requirements clearly stipulate in a transparent manner how the data are processed.  
The _right to erasure_ (Art. 17) is directly supported by SMARTEN, while the _right to rectification_ (Art. 16) can also be achieved indirectly in the same way. While the trusted key authority cannot delete the data, it can invalidate the keys of the data processor. Since all data are available only in encrypted form due to the signatures, invalidating the keys renders the data unusable. Rectification can be realized as a sequence of an erasure and re-submission of the corrected data.  
The _right to restriction of processing_ (Art. 18) is also enforced by means of the signatures. Only if the processing policy meets the required attributes, i.e., appropriate thresholds or adequate privacy measures, the data can be decrypted and processed.  
Since humans are involved in each phase of the data refinement process, i.e., data stewards as well as privacy officers in the preparation phase and data analysts as well as privacy engineers in the processing phase, a _fully automated data processing_ (Art. 22) is ruled out by default.  
By including third-party auditors as well as trusted authorities, _independent supervisory authorities_ (Art. 51 and Art. 52) are strongly involved in SMARTEN.  
Although only the most relevant aspects regarding applicable data protection regulations could be discussed here, overall it can be concluded that SMARTEN represents a comprehensive _privacy-by-design solution_ (Art. 25).