\begin{tabular}[Hbt]{| l | c || c | c | c |}
	\hline
	Requirement           & Focus & S1 & S2 & S3 \\
	\hline \hline
	\RF7: Encryption (\TODO1)       & +++ & x  &    &   \\
	\RF6: Authentication (\TODO2)   & +++ & x  &    &   \\
	\RG1: Security (\TODO3)         & +++ &    & x  & x \\
	\RG2: Reliability (\TODO4)      & +++ &    &    & x \\
	\RF8: Spam handling (\TODO5)    & +++ & x  & x  & x \\
	\RG4: Extendability (\TODO6)    & +++ &    &    & x \\
	\hline
	\RG3: Robustness        & ++  &    &    & x \\
	\hline
	\RF1: In/out channels   & +   & x  & x  & x \\
	\RF2: Mail queueing     & +   &    &    & x \\
	\RG5: Maintainability   & +   &    &    & x \\
	\hline
	\RF5: Route management  & 0   & x  &    &   \\
	\RF9: Malware handling  & 0   & x  & x  & x \\
	\RF10: Archiving        & 0   & x  &    & x \\
	\RG6: Testability       & 0   &    &    & x \\
	\hline
	\RF3: Header sanitizing & -   & x  &    &   \\
	\RF4: Aliasing          & -   & x  &    &   \\
	\RG10: Usability        & -   & x  &    &   \\
	\hline
	\RG8: Availability      & -{}- & x &    &   \\
	\hline
	\RG7: Performance       & -{}-{}- & x &  &  \\
	\RG9: Portability       & -{}-{}- & x &  &  \\
	\hline \hline
	Score (Sum of `+')      & 23  & 9  & 7  & 17 \\
	\hline
\end{tabular}