# A Usable Encryption Solution for File-Based Geospatial Data within a Database File System
## 5 Usability Analysis and Implementation of the Security Solution
### Usability Evaluation  
Our approach is based on the ISO 9241-11:2018 framework [60], where the usability evaluation is split into three sub-scales, including _effectiveness_, _efficiency_, and _satisfaction_. The two co-authors, who have several years of experience in GIS, carried out the evaluation. To this end, the tests correspond to _Non-Technical Single User Testing_[79].  
**Usability testing** was used to measure the security solution's usability. The two respondents were given ECMSDK user accounts named [PERSON] and [PERSON] and were asked to operate ten tasks twice (see Table 2). The time spent completing the tasks was documented. The respondents' failure to carry out the tasks was also recorded, whether it was due to them or the solution. Since using the solution is the same as using traditional file systems (except the part where users specify the files to be encrypted or decrypted), it incorporates a direct comparison with traditional file systems in enterprise GIS. The test carried out using [PERSON]'s account is shown in this video [[https://www.youtube.com/watch?v=zMJV5](https://www.youtube.com/watch?v=zMJV5) zV0-zs]([https://www.youtube.com/watch?v=zMJV5](https://www.youtube.com/watch?v=zMJV5) zV0-zs) (accessed on 18 April 2024).  
The **test procedure** primarily focused on the time taken and errors in the use of the encryption-decryption solution. Each pair of individuals in the test panel was asked to log in to the ECMSDK shared drive by mapping to it using their laptops. The solution is tested using the classical file-sharing protocol commonly used in enterprise GIS applications. Nevertheless, the model is the same if used by the other protocol servers provided by ECMSDK (that is, web, file transfer, or command line). The user-interaction model is illustrated for two GIS users, [PERSON] and [PERSON], who require access to single-user and multi-user spatial files. These files must be decrypted for use and encrypted back for protection in storage for a scenario for which both users are concurrently logged in. User [PERSON] has eight single-user spatial files (kx-site-of-significance-SHP shapefile dataset) and seven multi-user files (kx-nz-historic-places-SHP dataset). User [PERSON] needs access to these seven multi-user files as well as seven additional multi-user spatial files (lds-nz-bourly-islands dataset).  
In this study, the solution's **effectiveness** was measured using data on the number of errors committed by respondents. This includes the solution's inability to perform a task (Tasks 3, 6, 7, and 8). If these numbers is low, the solution already has a good level of effectiveness and vice versa. _Effectiveness_ was measured as the degree of task completion. The responses of the test panel on task performance were recorded as either \"complete\", \"complete with errors\", or \"incomplete\", and these were used for assessment. If a respondent's response deviates from the expected one, the reasoning behind his/her completion of the tasks was examined through analysis of the video recordings. Meanwhile, **efficiency** was measured as the time spent to complete a task (Tasks 2 and 4).  
To measure user **satisfaction** reliably, a validated psychological questionnaire is generally required, which can consist up to 50 items from categories such as _helpfulness_, _control_, _learn_, and _global_[80]. However, since our solution adds only a single additional step--specification of files to be encrypted or decrypted--to how users work in an enterprise GIS, we therefore believe that such an elaborate questionnaire was not necessary. Instead, we utilised the _Net Promoter Score_[81] metric and asked the respondents one question: \"_How would you rate the overall ease of use of our spatial file encryption-decryption solution (on a scale of 1 to 10)?\"_