\begin{tabular}[Hbt]{| l | c || c | c | c |}
	\hline
	Requirement           & Focus & S\,1 & S\,2 & S\,3 \\
	\hline \hline
	\RF\,7: Encryption (\TODO\,1)       & +++ & x  &    &   \\
	\RF\,6: Authentication (\TODO\,2)   & +++ & x  &    &   \\
	\RG\,1: Security (\TODO\,3)         & +++ &    & x  & x \\
	\RG\,2: Reliability (\TODO\,4)      & +++ &    &    & x \\
	\RF\,8: Spam handling (\TODO\,5)    & +++ & x  & x  & x \\
	\RG\,4: Extendability (\TODO\,6)    & +++ &    &    & x \\
	\hline
	\RG\,3: Robustness        & ++  &    &    & x \\
	\hline
	\RF\,1: In/out channels   & +   & x  & x  & x \\
	\RF\,2: Mail queueing     & +   &    &    & x \\
	\RG\,5: Maintainability   & +   &    &    & x \\
	\hline
	\RF\,5: Route management  & 0   & x  &    &   \\
	\RF\,9: Malware handling  & 0   & x  & x  & x \\
	\RF\,10: Archiving        & 0   & x  &    & x \\
	\RG\,6: Testability       & 0   &    &    & x \\
	\hline
	\RF\,3: Header sanitizing & -   & x  &    &   \\
	\RF\,4: Aliasing          & -   & x  &    &   \\
	\RG\,10: Usability        & -   & x  &    &   \\
	\hline
	\RG\,8: Availability      & -{}- & x &    &   \\
	\hline
	\RG\,7: Performance       & -{}-{}- & x &  &  \\
	\RG\,9: Portability       & -{}-{}- & x &  &  \\
	\hline \hline
	Score (Sum of `+')      & 23  & 9  & 7  & 17 \\
	\hline
\end{tabular}