# A Usable Encryption Solution for File-Based Geospatial Data within a Database File System
## 5 Usability Analysis and Implementation of the Security Solution
### Results  
Based on the preliminary study, the spatial file storage security solution was easy to operate for prospective users. The same user interface, that is, a file-sharing client, is used as before, while the only additional task is the specification of files for encryption and decryption. Figures 3 and 4 show two screenshots from the usability testing, while the complete user-interaction model (14 screenshots) is included as part of Supplementary Materials. The screenshots highlight the encryption-decryption aspect, the enforced ECMSDK access control model security and demonstrate how these security aspects are incorporated on top of existing enterprise GIS workflows for increased file protection. \begin{table}
\begin{tabular}{r l r} \hline \hline
**Task** & **Description** & **Figure** \\
**ID** & & \\ \hline
1 & [PERSON] logs in to his ECMSDK home folder using a mapped network drive. & Figures S3 and S4 \\ \hline
2 & [PERSON] notes the _single-_ and _multi-user files_’ decryption times. & - \\ \hline
3 & [PERSON] ensures the _single-_ and _multi-user files_ are decrypted and not corrupt. & Figures S5 and S6 \\ \hline
4 & [PERSON] logs out and notes the _single-_ and _multi-user files_’ encryption times. & - \\ \hline
5 & [PERSON] removes the \"_enc_\" file extension from the _single-user file_ for use. & Figure S7 \\ \hline
6 & [PERSON] logs in and checks if the _multi-user files_ have been decrypted. & Figure S8 \\ \hline
7 & [PERSON] ensures [PERSON]’s login did not corrupt the _multi-user files_. & Figure S9 \\ \hline
8 & [PERSON], after using the _single-user file_, appends the \"_enc_\" file extension. & Figure S10 \\ \hline
9 & [PERSON] and [PERSON] logout. & Figure S11 \\ \hline
10 & [PERSON] ensures that the _single-_ and _multi-user files_ are encrypted back. & Figures S12 and S13 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Usability evaluation tasks for two participants using the _[PERSON]_ and _[PERSON]_ user accounts. Effectiveness focused on user mistakes or the solution’s errors made while carrying out these tasks, while efficiency relates to the time taken. The last column refers readers to the figure in Supplementary Materials online that shows the tasks being carried out. Figure 4: [PERSON]’s logout encrypts back only seven multi-user files, and the remaining seven multi-user files are unencrypted for [PERSON], as he still has an active session. Figure 3: [PERSON]’s single- and multi-user GIS files are decrypted for use upon his login. ECMSDK ACM security prevents [PERSON] from accessing [PERSON]’s home directory. The two aforementioned figures demonstrate how the security solution handles user concurrency. They illustrate how (double) encryption is prevented for multi-user files when a privileged user ([PERSON]) logs out but another privileged user ([PERSON]) still has active sessions. Prevention of (double) decryption when these files have already been decrypted is shown in Figure S9 within Supplementary Materials online. In usability testing, a low number of errors indicates that the solution is _effective_ and vice versa. During testing, no errors from users or the solution were observed when the encryption-decryption solution was used (see Table A1). This is largely due to the solution's simplistic design, and this concludes that the solution is very effective. _Efficiency_ measurement was conducted by comparing the time needed by the respondents to decrypt and encrypt [PERSON] and [PERSON]'s _single_- and _multi-user files_ in the first and second repetitions. The combined encryption times are presented in Table A2. Since there was no other overhead associated with decryption or encryption, these times are similar to those included in Table 1. The respondents completed the tasks within the expected times in the first repetition since there were no errors. Our testing determined _user satisfaction_ with user responses to one question. The two respondents gave high scores (that is, 9) for their overall ease of use of our security solution (see Table A3).